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Everything posted by Laurie

  1. The 'Tactical' K31

    How to enhance your Schmidt K31 for the 21st Century, or .... or ruin it depending on how you view this sort of things? http://www.thefirearmblog.com/blog/2018/03/16/k31-sniper-chassis-system-wyssen-defence-switzerland/ (Note price - 1,850 Swiss francs = around £1,400. So you could buy three or four K31s or a whole collection of vintage Schmidts for that money, but not a genuine K55 Swiss sniper model I imagine.)
  2. 180gn 7mm berger VLD freebore

    There is a discussion about this on Accurate Shooter Forum as to exactly which reamer print dimension is the 'freebore'. http://forum.accurateshooter.com/threads/what-do-you-consider-the-freebore.3947801/
  3. Berger, MATCH TARGET BT?

    This is what Berger used to market as one of its LTB models. (LTB = Length Tolerant Bullet.) It is a HPBT Match design with a tangent ogive nose. Berger generally (but not guaranteed) produces three 'Target' designs in its key weights for calibres used for competition: the plain-Jane 'BT'. (Tangent ogive, easy to tune and seating depth tolerant.) VLD (Very Low Drag). Secant ogive, often very 'finicky' over seating position. Hybrid .. a modified VLD whose lower nose profile transitions from a secant front end into a tangent type junction with the bearing surface. Supposedly, it gives the reduced drag benefits of the VLD form with the length tolerance of the BT. (But, not always in practice, alas.) Berger's three 180gn 7mm models have the following characteristics and G7 BCs. BT ................... 9.08 calibres radius tangent ogive nose. Tolerant of seating depths / jump settings. 0.314 G7 BC VLD ................ 18.79 calibres radius secant ogive nose. Slightly longer OAL than the BT. 0.348 BC Hybrid ............ mixed form nose section, slightly longer OAL than the VLD; 0.345 BC. (ie the same as the VLD but less finicky about seating depth / jump.) A 9-twist rifling pitch is optimal for the BT, but marginally 'slow' for the other two. (In practice most F-Class 284 and WSM shooters use 9-twist barrels with very good results with the VLD / Hybrid.) The 7mm 180gn BT no longer appears in Berger's product lists, so has presumably been replaced by the Hybrid model. IME, the Berger BT models shoot very well in most calibres / cartridges. If you are able to source this obsolescent model at a good price, I'd say take them. However, if maximising BC for 1,000 yard shooting is high on your list of priorities, the Hybrid is superior with its ~9% higher BC value.
  4. Seating Depth Rule of Thumb

    I've started a thread on the Bryan Litz / Applied Ballistics supported section of the Accurate Shooter Forum to see if Bryan has managed to find any answers in the eight years since he asked the question about what is going on here. http://forum.accurateshooter.com/threads/bullet-nose-profile-and-seating-depth-sensitivity.3948062/ I'm not confident that we will get any new insights, but it's always worth asking.
  5. Seating Depth Rule of Thumb

    I said I'd come back on this issue, but having researched it as much as I can, there is very little around on this matter of ogive form and why some jump levels work and others don't. If you take Bryan Litz's 2009 words as copied into my post on March 2nd, AFAIK there hasn't been any progress here - in other words, we didn't really know how or why seating depths affected precision back in 2009, and still don't know today.We just know that it does and that it matters much more or less with some shapes of bullet than others. Here's what Bryan Litz says in Chapter 16 ('Anatomy of a Bullet') of his original edition of Applied Ballistics for Long Range Shooting: After explaining the difference between tangent and secant form ogives and how they affect drag, and the importance of nose length as opposed to shape, so far as this (precision and seating depth) aspect goes Litz says: ............ Almost all ogives are circular arcs. The circular arc will be either tangent to the bearing surface or secant to the bearing surface. If the arc joins the bearing surface smoothly, it's called a tangent ogive. If there is a visible abrupt junction between the bearing surface and ogive, then the ogive is secant. He explains the optimum drag-reducing nose profile for a secant ogive is double the radius (in calibres) of a tangent equivalent (ie same nose overall length). So if a tangent design has a nose radius of 7 calibres, the secant type is optimised at around 14 calibres radius. The Rt/R ratio that is a shorthand / guide as to what type a bullet is, is the ratio of actual nose radius to that of a true tangent form, so if a given length nose in a given calibre is tangent at 7-calibres radius profile, a true VLD secant form will be 14-calibres and its Rt/R is 7 over 14 = 0.5. If it has an 11-calibre radius, the Rt/R value increases to 0.64 and if it is a true tangent form it is 7 divided by 7 = 1.0. So a combination of a long nose and a high-value nose radius gives the best result in terms of drag in supersonic flight. But the downside is the seating depth / precision issue. So far as just the profile is concerned, Litz says that the secant type can reduce drag by as much as 12% over tangent for two designs with the same nose length. The downside is the abrupt shank to bearing surface junction in a secant ogive bullet, of which Litz says here: ..... Bullets with secant ogives are known to be finicky in relation to seating bullet depth. A popular notion is that the more abrupt nose/body junction for the secant ogive doesn't self-align itself in the riflings as well as a tangent ogive bullet. A common solution is to soft seat the secant ogive bullets into the lands, thereby eliminating bullet jump, and minimizing the potential for misalignment as the bullet starts down the barrel. ..................... He goes on to say it is also more difficult to manufacture consistent bullets with secant ogive profiles and very high quality jackets are needed to avoid wrinkles. So, there isn't a great deal of science at play here. This is empirically gained knowledge - we know this works or doesn't, but the reasons are mainly supposition. This of course is very much the case too with traditional FMJBT or FMJ tangent designs whose origins are all military and result from huge amounts of on-range testing of various designs and tweaking of designs a long, long time ago. If the research work was ever published at all, it's impossible to find it now. The Swiss (Major Rubin) were in the lead here and the 174gn FMJBT as loaded in the 7.5X55mm GP11 was an outstanding long-range bullet for 1911 (and still is which is why the Swiss still use it in the MG51 machinegun). The Finns followed in the 20s and 30s with the D-series rebated boat-tail bullets which are also still in use today. The objective of the D-series was bullets that reduced barrel wear compared to a conventional FMJBT, were less affected by it and which retained dynamic stability in ELR shooting of 4,000 metres plus. (Not the same thing as BC whose maximisation sees our modern super-long pointy designs, but which become prone to instability at ELRs.) Just how good the D-series is with regard to shrugging off throat wear (and hence presumably misalignment) can be seen in the reprints at the bottom of this Accurate Forum topic page with embedded copies of a Finnish Army trial with the 7.62X53R which primarily looks at bullet size / match to the barrel but tells us more. For the full-size bullet, precision peaked, (ie average group size was at its smallest) at 14,000 rounds down the barrel, and thereafter steadily rose. You can correlate throat wear to precision through the two graphs. One wonders how a modern VLD would have coped here. (Badly one imagines!) The other thing that I took from this was how good barrel life is with a mixture of a sub 45,000 psi cartridge and chrome-moly steel barrel. http://forum.accurateshooter.com/threads/243-barrel-life.3934900/page-2 In the past we had two designs - tangent (high drag but seating depth tolerant) and VLD (low drag but seating depth intolerant), then we got a third type, the Berger Hybrid that sees a secant profile ogive transition into a tangent type seamless bearing surface to nose junction. Problem solved, best of both worlds. But is it so, and for that matter is it a new design? As to the latter question, the Hybrid is actually a VLD, but with a 'fix' to try and overcome the VLD's main disadvantage. I'm not at all convinced the 'fix' always works ... or even works at all! The few models I've used 1) aren't at all jump tolerant like a 'traditional' Berger BT or Sierra MK tangent design, and 2) seem to vary (markedly sometimes) as to what works best. For instance in 30-cal, the 155gn Hybrid only shoots well for me in 308 Win with a large (40-50 thou') jump. In the lands or 10-20 thou' jumps give very poor results. The 168gn Hybrid won't shoot with normal jumps for me but needs to seated in the lands like a common or garden non-hybrid VLD. (I'm not alone with the 168 and have this finding confirmed by others.) As I pointed out in my post of 1st March, Berger's flagship 308 bullet now is NOT a Hybrid, but a long-nose tangent design whose Rt/R ratio is 0.97 and as close to true tangent as you'll get. The nose length is 0.848" out of a bullet OAL of 1.508" and with a short bearing surface in relation to the other dimensions of 0.413". That nose length is the same as those of the 215 and 230gn Hybrids give or take a few thou' and identical to that of the new 225gn Hornady ELD-M. A very long bullet with a very long nose, and I have heard rumours that some wind conditions can throw the 200-20X performance right out at very long ranges, presumably as a result of its approaching or entering transonic speeds at 308 Win MVs and maybe suffering stability issues due to its length. (If the bullet is very / over long in relation to its calibre, it risks becoming dynamically unstable at extreme ranges, and spinning it faster through a tighter rifling twist will reduce that tendency a little but won't cure it as spin-rate affects gyroscopic stability, a different aspect of bullet behaviour.) Having spent a lot of this miserable winter studying Litz's third edition of his book Ballistic Performance of Rifle Bullets (over 950 bullets now described and tested), I've decided that going past headline form factor and BC figures is well worth doing and looking at bullet shapes and dimensions shows that many of the 'rules' about company A making this kind of bullet and B the other have been torn up and thrown out the window. The manufacturer will trumpet BC all day in its literature and website, but what about bullet and in particular nose profile? I've praised the 0.284" 160gn TMK a lot here and elsewhere. Lovely bullet, good if not outstanding BC, very easy to tune and it stays 'in tune' over a lot of rounds down the barrel so no 'chasing lands' here. Look at it and it is a reasonably long-nose tangent type whose Rt/R is quoted as 0.84, same as the old 'traditional' form 175gn SMK that I consider an outstanding and much under-appreciated 7mm bullet. So ... (foolishly) I assumed, all the new TMKs would have similar characteristics. NOT necessarily so. 0.224 69gn TMK ............... 1.00 0.224 77gn TMK ............... 0.96 0.243 95gn TMK ............... 0.81 0.284 160gn TMK ............ 0.84 0.308 155gn TMK ............ 0.55 0.308 168gn TMK ............ 0.54 0.308 175gn TMK ............ 0.55 0.308 195gn TMK ............ 0.46 So, you get nice seating depth tolerant designs in 22, 6mm, and 7mm, but when you get to .30 you find a quartet of out and out VLDs. (Did you wonder why you've maybe struggled to get the new 175 to shoot well when the old SMK of the same weight is such a sweetie?) With Hornady, you assumed usually correctly, you always got a secant quasi-VLD type with the Amax models, how about the new ELD-M designs? (Amax Rt/R in brackets after the ELD value). 0.224 73gn ELD-M ............. 0.67 (-) 0.224 75gn ELD-M ............. 0.48 (0.68) 0.224 80gn ELD-M ............. 0.50 (0.67) 0.243 108gn ELD-M ........... 0.91 (0.74 105gn) 0.264 120gn ELD-M ........... 0.57 (0.56) 0.264 123gn ELD-M ........... 0.86 (0.43) 0.264 130gn ELD-M .......... 0.67 (-) 0.264 140gn ELD-M .......... 0.84 (0.72) 0.264 147gn ELD-M ......... 0.81 (-) 0.284 162gn ELD-M ......... 0.50 (0.55) 0.284 180gn ELD-M ......... 0.60 (-) 0.308 155gn ELD-M ......... 0.55 (0.57) 0.308 168gn ELD-M ......... 0.51 (0.58) 0.308 178gn ELD-M ........ 0.85 (0.56) 0.308 208gn ELD-M ........ 0.81 (0.68) 0.308 225gn ELD-M ........ 0.67 (0.69 - 225gn HPBT Match) So, a mixed picture for this make. The 22s (75/80) have become very much more VLD type; some have stayed the same; but a significant number should now be much more jump tolerant than their AMax predecessors, in particular the 108gn 6mm, 123gn 6.5 and the 178gn and heavier thirties. MOREOVER ..... Hornady really has reduced drag / increased BC in its ELD range as the company claims. Despite the doubling of the 123 6.5's Rt/R value, the new model has an improved BC. The new 162gn 7mm has an outstanding BC for its weight - shame it's an out and VLD, but I've bought 200 anyway to try in my 7mm-08 and 284 F-Class rifles. The 140 and 147gn 6.5s have both good Rt/Rs and low drag shapes. (The 140 AMax BC increases from 0.288 G7 to an outstanding 0.322 which is higher than the Berger Hybrid's; the 147gn is rated by Litz at 0.335.)
  6. The 'Tactical' K31

    Hmmmm ... I could persuade Craig at Evo Leisure to make me a couple for my old 7X57 Mauser service rifles, 29 inch barrels and all, ........... but with tubular slotted hand-guards they'd look like MG34s and frighten the natives. ..... or maybe I could come to love a chassis stocked 303 SMLE. (In this form, the ultimate 'battle rifle'?) Nah, on long and mature reflection of maybe 10 seconds, they're not me Vince. Dolphin F-Class stocks are as much as I like in the way of alloy superstructure.
  7. 308 dies neck size only

    They should have. The expander button can be dispensed with if required and the die will still decap cases as there is a decapping pin retaining collar separate from the expander button. http://www.redding-reloading.com/online-catalog/118-type-s-bushing-dies The carbide expander upgrade involves a new stem and converts the button to floating operation. The Type 'S' FL die in this form is an excellent piece of kit - expensive though!
  8. 308 dies neck size only

    If you use a neck-only die, you also need to use a body die alongside on most cartridges, unless running with very low loads / pressures. Cartridges in the 308 Win 'family' (308, 7mm-08, 260, 243) for instance will see the shoulder move forward enough on a single full-pressure firing to give tight chambering for maybe half the cases on the next loading, and the need to force the bolt-handle down on some cases in a third go. (This also shows up as witness marks on the shoulder and circular marks on the case-head as the bolt is turned against it on opening whilst under considerable pressure.) A longitudinally tight ('negative headspace') case to chamber fit of varying degrees does nothing much for consistency and precision and I have read that it also causes chamber pressures variations, although I can't see a mechanism for those to be produced. In times past I ran cartridges like the 308 Win sizing them with a Lee Collet die only quite happily, but with what I'd now regard as very modest loads and pressures. Returning to this particular tool on a 260 a couple of years back, I was taken aback as to how rapidly shoulders move with the pressure levels I run at these these days. The obvious alternative is a FL die, but standard models are brutal on the case as they over-size necks down considerably and then expand them heavily. A much better alternative is a bushing-style FL design or a Lee Collet + body die. I'd give three options, although there are likely more: 1) Forster Bushing-Bump sizer. This is a bushing neck-sizer, but whose die body also moves the case shoulder (ie 'bumps' it), the latter function set as per a normal FL die according to how much the die is screwed down in the press in relation to the shellholder. I use this type in both 223 and 308 FTR rifles with minimum SAAMI chambers. Despite running at some hefty pressures, I've never seen the need to FL size the case and after multiple firings Lapua Palma cases still chamber and extract very easily and with occasional annealing brass life is very great indeed in the 308 with its strong case-head. (223 brass goes in the bin after a few firings for expanded primer pockets.) However .... the Bushing-Bump die doesn't incorporate an expander ball, so unless neck-turned brass is being used, either one should be fitted or a separate expansion operation using a mandrel type die / expander employed for best results. 2) Redding Type S full-length bushing sizer. It works as per a normal FL die, but the degree of neck working is controlled by selecting a bushing size to match the brass in use and to size necks down only just enough so that every case is felt to go over the expander button, ideally slip over with so little resistance that you only just feel expansion taking place on the press handle. Redding also offers aftermarket carbide expander buttons which reduce brass working further. 3) An alternative either little known here, or if mentioned, scoffed at - Lee Collet NS die plus Redding (or other) body die in combination. This has become increasingly popular in Canada and the USA among FTR shooters, especially those using 223 for mid-range competition where the little cartridge is now regarded as the equal of 308, if not its superior. The body die gets the shoulder sorted and the Collet does the neck giving excellent consistency and concentric results with minimal brass working and no extra expense in bushings. It doesn't need the inside of the case-neck lubed which is in itself a big plus for many. IMO, this is an excellent method which I'll sometimes use myself, but the Collet's biggest downside these days is Lee's production quality - early examples many years ago were a joy to use while today's seem rough and often an over-tight internal parts fit, so people end up polishing the collet tines whose sharp edges to smooth up die operation and also to stop over-sharp internal edges chewing the neck surface up.
  9. 6.5 Creedmoor; Lapua case capacity & life

    Yes, there is much less interest in weight batching brass these days, especially if one of the better makes is used. Some people still do it, but many precision shooters have decided it is a complete waste of time. I still weigh Norma and Lapua brass out of the box, but purely now to identify the very occasional rogue individual that is way outside the curve. However, I've just bought 100 new PPU 243 Win cases for an upcoming project and a sample of maybe 30-40 cases ranged from 171.3 to 177.0gn a variance of 5.7gn on a median weight of 174.2 or 3.3%. In the days when people religiously weighed and batched brass (properly done after trimming and any other preparation such as neck-turning, uniforming primer pockets etc) the target was everything within 1% or 1.5% tops. Today, people speak of 2% being acceptable if not good ............ but based on what criteria? Out of interest, I'll see how many of the 100 pieces I can batch within 1.5% (2.6gn) and see if there is any noticeable difference in groups and/or ES and SD in a reasonable quality factory 'varmint' model rifle between the batched and the all-over-the-place weight lots. ALSO .... some time back, Edgar Bothers pressed a couple of 50-ct bubble packs of prepared ready to use 'Top Brass' cases onto me in 223 and 308. These are recycled military cases, cleaned, resized, trimmed, primer crimp rings removed etc - but goodness knows how many makes and year headstamps. I did explain that using brass like this in my FTR rifles is against my religious beliefs, but Edgars was insistent. So, I'll do a test of them at the same time for an eventual write-up in Target Shooter. I imagine, that they'll work fine for the short distance plinker and even fox or deer shooter. Here's a Gun Mart review of this brass by Pete Moore to let people see just what I'm blathering about. https://www.gunmart.net/ammunition/reloading/cases/top-brass-once-fired-cases
  10. 6.5 Creedmoor; Lapua case capacity & life

    It is low! Fired in an industry standard PT&G chamber, I got 52.5gn for what I regarded as the heavy case weight Norma and two batches of early Hornady brass gave 53.4 and 53.7gn, all fireformed. At 51.3gn, this version of the Creedmoor case isn't offering much more capacity than the 6.5X47mm Lapua whose fireformed brass gave me 48.8gn when I shot that number, an increase of a shade over 5%. As case capacity % change gives an MV % change of capacity variance in % divided by 4, that's only 1.25% or 35 fps improvement on a 2,800 fps load. (That assumes both cartridges are loaded to the same pressure and fired in the same barrel length.)
  11. 6.5 Creedmoor; Lapua case capacity & life

    From an internal ballistics perspective, the key factor isn't how a case has been sized, but what its internal capacity or volume is when it has obturated within the chamber under firing pressure. That is why QuickLOAD says use a fired unsized case from that rifle's chamber to obtain the case 'overflow water capacity' in order to produce more accurate results compared to the default value. The case expands in the chamber to grip its walls (thank goodness or we'd be in big trouble and/or need bolts built like downsized artillery pieces ) and its internal capacity is then at its maximum. That amount of space plus the volume of freebore ahead of the case that applies when the bullet has moved out of the case-mouth and has been stopped or checked in the rifling gives us and QL's equations the key initial combustion chamber volume, one of the primary metrics affecting peak pressure alongside powder grade / weight and bullet characteristics / weight. The fireformed and unsized case's capacity isn't quite that of the case in its obturated in-chamber form as the case shrinks slightly once pressure goes (again, thank goodness or we'd never extract it), but is so close as to make no difference. FL sizing can reduce the case overflow water weight reading considerably to produce a false value and reduce QL's accuracy. What this also means is that there are two factors at play in this issue - 1) the case's capacity as a result of how it has been made, wall and web thickness etc; and 2) the rifle chamber size. There may be a considerable difference in the capacity of a given make of fireformed case taken from a mass produced cheap sporting rifle and that of the same case fired in a custom build whose barrel has been chambered with a reamer made to 'minimum SAAMi / CIP' spec.
  12. Reloading with Rosie

    I sort of got dragged into this by a phone call the afternoon before the 'shoot' and honestly didn't have a clue as to who Rosie is. I imagined that Edgar Brothers had recruited her from a local ladies' seminary to paraphrase W S Gilbert .... but did wonder about the shorts ... tanned legs that go on forever .... and ... An interesting excursion and great fun. Giving you her phone number? What makes you think I have it my man? You can go on her official website like all the other old saddos!
  13. Swiss/Reloader Powders

    I don't think there is a direct RS canister equivalent. It apparently falls between Alliant Re22 and Re33 (RS80). That puts it in the same bracket as Re25, H1000, and IMR-7828 as an overbore capacity large magnum powder. Like RS70 and 80, it is a high-energy type incorporating Nitrochemie's advanced 'EI' deterrent infusion process which means it'll likely be a sector leader in potential MVs in optimal applications, but at the expense of accelerated barrel wear if loaded up to maximum pressures. (For the sort of cartridges it's suitable for, very high-performance sporting jobs for long-range game shooting, barrel life is a secondary consideration.) In the 28 Nosler super-overbore job, Nosler quotes an Re26 load of 79.0gn as maximum for the 160gn Partition and Accubond bullets. Playing around in QuicklOAD, this charge is seriously over-pressure in RS70, so it's definitely not that, nor is it RS80 which would run seriously under-pressure with this charge weight. For comparison, Nosler quotes slightly higher charges for Re25 and H1000, 80 and 81gn, so Re26 appears to be slightly faster burning than this pair, but produces almost as high velocity and with a lower fill-ratio. It'll be somewhat too slow burning for the 6.5X55. RS70 and Re22 are pretty well optimal for this cartridge with 140s and H1000 is too slow burning.
  14. Ha! Ha! You can hardly see the D Range shed 200 yards away never mind the targets. (Looks a mite chilly too, but since Mole-e30 and his BR HG match winning daughter Emily are currently spending their nights in an igloo built in their garden - really, I'm not kidding here, mad as a barrel of frogs - they'd likely shoot even better than usual when surrounded by melting snow and in below freezing temperatures.)
  15. I doubt it. The 175gn SMK is a lovely bullet - very jump and throat tolerant which is a plus in a throat-eroding cartridge like the 7mmRM - and despite having been around for many years is still a very efficient design in external ballistics terms. N560 is very well suited to the cartridge characteristics. There is not a great powder choice thanks to 'Reach' - Norma MRP and Alliant Re22/25; Reload Swiss RS70 and 80. The new Viht N565 might suit, but I suspect is too slow burning given that 560 is nearly spot on in this respect. Viht N165 will reduce barrel wear considerably, but likely lose you 100 fps MV compared to N560. For long-range match shooting, you might do better with something other than PPU brass. My limited experience with this make (243 Win) is that appears to be very well made, but has a large weight spread (~7gn in the 243) suggesting that internal capacities will vary a lot too - no great issue for short-range, but it'll have an effect beyond 600 yards.
  16. Re the 28 Nosler, ELR type use shows promise because of the very low string counts. How well it'd compete ballistically against the 375s and 40+ calibre numbers winning the Ko2M and similar, I've not a clue. I'd doubt if it'd be much use in F-Class unless you dropped loads considerably. (In which case, it's much better to use the 7WSM!) You have two problems in F. First, I think you'd struggle to get through a 2 + 20 match especially on a warm summer day. Barrel temperatures will kill precision and consistency before the end of the match. Allied to that, you will kill the barrel very quickly. Also recoil and torque will be heavy. In a 22lb rifle (F-Class ceiling) 88gn RS80 and a 180gn bullet at 3,300 are calculated to produce a free recoil speed of 7.2 fps and energy of 17.5 ft/lb. A few years ago, it looked like the .300WSM and 230gn Berger Hybrid might take over from the larger sevens as the external ballistics looked very good. They didn't, one reason being that users found that the recoil / torque made then hard to shoot consistently over 20 shots in a match. That cartridge's recoil values for a bit over 60gn powder charge and 230 at 2,800 fps works out at 6.1 fps free recoil velocity and 12.7 ft/lb energy, way lower than the 28 Nosler's even in such a heavy rifle. That's not to say anything's impossible. IIRC Year 1 of the GB F-Class League was won by Pete Wilson shooting the 7mm BooBoo whose case has 90gn water capacity. As smaller sevens were developed though, this cartridge was very quickly sidelined. Elwood and Desparado would be able to comment much better than me on the feasibility of such a large seven in our F-Class as the Shehane is the largest case cartridge I've used in the 7mm calibre. By coincidence, I was looking earlier today at what one or two recent loading manuals say on the 28 Nosler and 7mm RUM. Lyman says that groups / strings should be limited to three shots on the RUM and then allow complete cooling (not surprised with that vast case and huge powder charges). The authors laud the 28 as a long-range hunting cartridge, but warn that those considering it must be aware of the downsides, primarily recoil and short barrel life. It recommends checking barrel throat condition regularly after about 500 rounds, presumably based on experience with the test barrel used in load development. This would be on the basis of its use as a 'hunting round' and I've no doubt that the Lyman lab staff took that into account with very short strings and lengthy cooling-down periods between them. In range use where matches see 17 or more usually 22 shots fired, I think you can take that figure and halve it. Defining over-bore capacity is a real length of string job, but to give an idea of where the Nosler stands, this case capacity to bore area table is a useful guide. http://bulletin.accurateshooter.com/2016/03/defining-overbore-cartridges-the-great-debate/ The 28 Nosler exceeds anything in the table with an index value of 1,522 (95.9gn water capacity divided by 0.063 sq in, the area of a 0.284-in dia. circle). As a baseline, many people fail to realise that the 243 Winchester is actually a very over-bore design as it is such a common and apparently non-exotic number. In this indexing method, it has a value of 1,164 and here's what a Bartlein Barrels engineer says about it: First question that needs to be asked is.....What is your accuracy requirement? This will determine your barrel life more than anything else. A bench shooter or F class shooter will normally have a different accuracy requirement vs. a shooter using it for deer hunting etc...How the barrel is made, type of powder, type of bullets, type of shooting, how it's being cleaned and how often, rate of fire etc... all effect barrel life.If we do testing here in regards to steel and barrel life etc...we use .243win. because it is a barrel burner. Ammo makers are not fond of the round for the simple reason at approx. 1000 rounds they are replacing pressure test barrels. The wear is so heavy that it will start to get inconsistencies in pressures and velocities and if loading for Saami spec. ammo they have to hold a given pressure spec. and once they start to vary they pull the barrel.Later, FrankBartlein Barrels
  17. For this purpose the Creedmoor is the obvious contender as a smaller calibre 308 replacement, superior in every respect bar barrel life. For the Creedmoor and also the 260 Rem in longer-range magazine fed operation, look at the 130gn Berger AR-Hybrid which I reckon may be a game-changer for such rifles in magazine operation. It's been developed for the 260 Rem for use in 2.800 COAL loadings in - as the same suggests - semi-auto match and tactical rifles and manages to produce an impressive BC despite having a shorter nose section than more traditional 6.5s. I'll give some a go in a long-throat 260 later this year including running them with really large jumps (as in 150 or more thou'). Not a cheap bullet though.
  18. As you have a rifle whose action and bolt are set up for magnum case-head cartridges and long COALs, the 7mm Rem SAUM would be worth consideration if and when rebarrelling comes due. This version of the short magnums appears to be gaining popularity rapidly these days, so this year's long-range match results should show if its day has finally come.
  19. I researched this in some depth a few years ago before rebarrelling a 308 FTR rifle to 7mm-08, subsequently done with a 31-inch Bartlein fluted 9-twist - thank you Mik Mak and Dolphin Precision for a good job! In factory or custom sporting rifles, the 7mm-08 is severely limited by magazine length and the SAAMI COAL of 2.800". That's why factory ammo is mostly 140gn PSP with one or two 150gn offerings. Despite this, it is reckoned by many to be one of the best light/medium deer cartridges on offer, a 7X57mm Mauser for modern rifles and today's expanding bullets. As a range / prone deliberate competition tool, it needs to be on a long action or a short action used single-shot in both cases with an extended freebore chamber. The match 7mm-08 needs to run at around 2.95-3" COAL for mid-weight bullets such as the 160gn Sierra TMK, 162gn AMax / ELD, and 168gn Berger VLD, and slightly more for 175gn and heavier models. (The same of course applies to 260 Rem with 140-150gn bullets among the 6.5s.) The cartridge will handle 175/180s in match form, but the case capacity is marginal for the slower burning powders used - my opinion is if you want to shoot these bullets go up a step in case size to the 'straight' 284. If you take the 168gn Berger VLD as the default bullet - I did and the barrel was chambered around it set at 2.99" COAL, pity the Bartlein has never liked this bullet much! - you have an aerodynamically efficient design with 0.925 form factor giving 0.322 G7 BC (Litz). That's a not unimpressive figure considering the darling of the 'Effers' shooting big boys' sevens, the 180gn Berger Hybrid is rated at 0.345, only 7% higher. However, look at the 6.5mm competition and the obvious comparison is with the same source and similar vintage 140gn Berger VLD whose form factor / BC values are a not too different at 0.936 / 0.307. (Actually, taking these figures from Bryan Litz's Ballistic Performance of Rifle Bullets 3rd edition, Bryan has revised one of both as the two bullets had identical BC values when I did the research using data from the 1st edition.) What I took from the figure work was that with bullets having similar BCs, you need similar MVs to have comparable external ballistic performance between 6,5 and 7mm cartridges and as the 260 etc in long-throat (LT) match form would give a 140 0.264 bullet around 2,800 fps, that or more had to be the 7mm-08 objective for the 168 VLD. The Litz revisions ease that target a bit, but we now have the Hornady 140gn 0.264 ELD-M with a G7 BC of 0.322 as per the 7mm 168, and a 147gn version at a very impressive 0.355. (On the other side of the balance sheet, the new Hornady 7mm 162gn ELD-M is rated at 0.327, a little higher, and being a little lighter can be driven a bit faster, in theory anyway. I then spent many happy hours modelling 260 Rem LT v 7mm-08 LT and the conclusion was that unless you really stoke the 7-08 up with hot burning double-based or high-energy powders, the 260 in long throat form has the edge as in QuickLOAD at any rate, an extra 50-100 fps is on offer. Since then, small primer 6.5 Creedmoor brass has appeared and we're starting to see some impressive claimed MVs for handloads for this cartridge in this form. The other side of the equation is of course barrel life. I reckon that the 7-08 with single-based powders and warm but not excessive pressure loads should give up to 50% greater barrel life than hot loaded Creedmoors / 260s. (Say 3,000 rounds v 2,000, but with some of the MV claims for SR 6.5 Creedmoor and 140-147gn bullets, I frankly doubt if these rifles will see as much as 2,000 rounds through a barrel!) In the end I settled on the 160gn Sierra TMK at 2,830 fps from a compressed load of Viht N160 for mid-range F and for short-range F, the 150gn Lapua Scenar L at 2,850 fps using Lovex SO65, a modest pressure and ballistic performance load but one that will chew the centre out of the 300 yard F-Class target and produce groups in the twos with some high ones off the bench at 100 yards in nil/low wind conditions. I have avoided hot powders - RS60, N550, and suchlike - but have loaded 50 rounds up recently to try at 100 with Hunter, RS62, and N550 to see what level of MVs can be obtained. I've also just bought a couple of hundred of the higher BC 162gn Hornady ELD-Ms to see what their precision is like - the 160 TMK shoots so well in the rifle that it has to be an exceptionally good-grouping combination for me to replace it irrespective of the bullet's BC. With hindsight, the 7-08 needs such relatively slow burning powders with >160gn match bullets, that I'd choose 7mm-08 AI now rather than the 'straight' version whose case is just a bit short on capacity. (The same applies to 260 of course.) 7mm-08 brass is no problem - Winchester is actually rather good, but the obvious source for the match shooter is Lapua .308 Win 'Palma' small primer - a single pass through a 7mm-08 FL sizer reforms it although it does thicken necks by a thou' so mild neck turning may be necessary for a 'minimum SAAMI' chamber.
  20. My advice would be to forget you now have! Nosler sees itself as a modern US equivalent to H&H, Rigby and such selling upmarket rifles and its own design cartridges at inflated prices. (Rigby etc it is NOT as while it markets nice rifles, they're hardly hand-built by craftsmen.) Nosler's proprietary cartridges are nearly all seriously over-bore capacity as they're designed to produce a headline grabbing MV figure for marketing reasons. Rifles and ammunition generally get a good press from American shooting journos - not surprising as the individuals concerned do their 'testing' on live hunts of exotic species in exotics places with five star accommodation and catering for several nights at Nosler's expense. Say anything remotely negative in print and that gravy train will never be boarded again. Here are the case water capacities of a range of 7mm cartridges in grains weight: 7-08 ................................................ 55gn 284 ................................................. 66gn 280 Rem / 7X64 Brenneke .............. 69gn 7mm RSAUM .................................. 73gn 7mm Rem Magnum / WSM ............ 81/82gn 28 Nosler ...................................... 95.9gn (Nosler data) 7mm RUM .................................... 112gn The 7mm Rem Mag has been used as an off the shelf example of an over-bore capacity design for decades, although it is less so these days given the arrival of much slower burning powders such as Hodgdon Retumbo. Nevertheless, it is a big high case capacity cartridge for the calibre. With a 17% capacity increase over it for the Nosler, you burn a lot of extra powder for a very small MV hike, but at the expense of even worse barrel life. OK for people who fire less than 20 rounds a year in a sighting-in session then a couple of elk or moose hunts, but really, really useless as range tool. To compound it, while you can get 7mm RM brass at reasonable prices easily, and SAUM and WSM brass for somewhat more with some hunting around for suppliers, the 28 Nosler is only supplied by Nosler at Nosler prices. (Actually, they're probably made by Norma under contract.) Sportsman Gun Co currently has an offer price on it of £94.99 per pack. Not unreasonable? Note the pack size - 25 cases so £379.96 / 100 (+ P&P ) I could go on, but ............................... !!
  21. 7x64 Brenneke handloading tips

    I should have qualified my reply to say N560 which is very much slower burning than N160, and in fact often acts as a slower burning powder than N165. My experience is that it can be finicky and also need max pressure loads to perform consistently. In sporter length barrels, one symptom of it being unhappy is muzzle flash like I've never seen with anything else! Viht doesn't list this powder with any bullet weight in the cartridge. N550 should be happier, but if you look at the recently revised Viht data, both N550 and N160 are shown for the 160gn Nosler Accubond, the nearest to what you're using. N160 perhaps a little surprisingly gives another 50 fps over N550. Hornady in its most recent manual has data--sets for both 280 Rem and 7X64, but no Viht powder loads - in fact there is not much Viht data in this manual anymore and recent additions like the 6.5 Creedmoor have none at all (likewise Sierra). Both it and Lyman 50th just out (for the 280 alone here) show best results from IMR-4350 and for best MVs IMR/H4831. So, this gives an indication of post-Reach alternatives: IMR-4451 (for 4350) and when it arrives IMR-4955 (for the 4831s) Viht N160 which despite being shown as equivalent to IMR-4831 in most burning rate charts often acts more like the 4350s and at the least is somewhere between the 4350s and 4831s. See Viht's data. Viht N550 Ramshot Hunter (Hornady lists 52.6gn max for its 162s for 2,600 fps in a 22-inch barrel Sauer 101, not the highest MV in the table) QuickLOAD computes another 90 fps from this combination for nearly 2,700 fps and a very good match to the cartridge and bullet. (Using the 162 AMax as I don't have the ELDs in my version.) Alliant Re19 and 22 should both work. QuickLOAD suggests Re19 is an excellent match ballistically, but if you're chasing MV several more grains Re22 and a compressed load gives almost as high MVs as you can safely get. Reload Swiss lists loads for the 7X64 but the nearest bullet to the Hornady 162 is the 168gn Sierra MK and shows loads for RS60 / RS62 / RS70 / RS80. (80 is hopeless - far too slow burning.) QuickLOAD suggests RS62 and RS70 are excellent matches.
  22. 7x64 Brenneke handloading tips

    You may encounter considerable muzzle blast and flash with anything under a really high pressure load.
  23. 7x64 Brenneke handloading tips

    The 7X64 is very close dimensionally and ballistically to the 280 Remington although neither brass nor loaded cartridge is interchangeable. (Actually, it's the other way round as 7X64 is very much senior to the US upstart near-copy!) The advice on loads is to use 280 Rem data and subtract 5% from the maximum for safety. So look up pet loads on the 280 if you don't find much on the Brenecke. Redding Deluxe are standard non-bushing dies. Good quality IME. If the neck tension is too high, remove the expander in the sizer die and get or if you already have one use, a mandrel type expander die which allows interchangeable mandrels designed for expanding the neck before neck-turning. I use the Sinclair expander die body and the same company's 28E model expander on all my match sevens and the degree of neck tension is just where I want it. The K&M equivalent should be fine too. Lube the inside of the neck before use, or else shell out for a very expensive carbide mandrel. https://www.vihtavuori.com/reloading-data/rifle-reloading/?cartridge=82 I'd have thought N160 is well suited to the cartridge, N165 for 170gn and heavier.
  24. M62

    Saw that pic on Facebook yesterday, only the caption on that version said: Hello, any chance of a lift to Milton Keynes?

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