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About Laurie

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    Advanced Member
  • Birthday 10/05/1949

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    F-Class, BR, and any form of target shooting that involves a scoped rifle, but doesn't require shooting offhand

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  1. Laurie

    Sierra 155gr TMK for mid/long range?

    That G1 BC will only be one of a series of velocity-banded values, and by its looks the highest of the bunch. Litz (Ballistic Performance of Rifle Bullets 3rd edition) gives it an average G1 of 0.464. The far more useful G7 average is 0.238 (compared to the old 175's 0.243), good but in no way groundbreaking. By comparison, the 155 Berger Hybrid is 0.245 and the easy to tune 155.5gn Fullbore BT is 0.239. The antediluvian 155gn Berger VLD is in effect also so close as to identical for all practical purposes at 0.239 G7 average. The reason I mention this bullet is that the 155gn TMK is exactly that - a full-blown VLD form type with a very long (0.804") 13.39 calibres radius nose section and Rt/R nose juction form of 0.55 (0.50 = perfect / classic VLD). The old 175 has a shorter blunter front end with a longer shank in relation to the whole. Rt/R is 1.00 (perfect tangent ogive) and its nose radius is the classic SMK 7-calibres, these features making it one of the best behaved, easiest to tune designs that will accept worn throats, large jumps, etc, etc. Bearing in mind it was developed at the request of the US Army for use in the Remington manufactured M24 military adpatation of the Remington 700 and M118LR 7.62mm cartridge, it does everything it says on the tin - accepts Remy's long throats and works in a everything from a newly made or refurbished job to one with 5,000 rounds plus on the clock in all conditions and weathers. This is a classic trade-off: tolerance v form factor / BC, although some designs such as the 155.5gn Berger BT manage to combine good manners with low drag behaviours. The new TMKs in the various calibres are a heterogeneous collection - there is no 'theme' to them ranging from tangent to aggressive secant (VLD) forms, although there appear to be more of the latter. The 308s from 155 to 193gn are all VLD types with 13 to 14 calibre radius secant ogives and Rt/Rs from 0.46 to 0.55. By comparison, the 160gn 7mm TMK is like many modern high-performance bullets a half-way house job with a 10-cal radius nose and Rt/R of 0.84, nearer tangent than secant / ogive and I've found it an easy design to get to group well when jumped.
  2. Laurie

    FTR Newbie

    The price gap between the Dolphin FTR and Savage FTR is not as great as it once was as Savages are not the bargain they used to be and cost around £1,800 new these days. The 'basic' Dolphin with Nesika E action adds up to £2,650 if you avoid bling extras such as barrel fluting, or £2,550 for the same rifle with the Barnard 'S' action. If you do need to rebarrel the Savage after a year's experience, the cost will be the difference between new rifle prices, ie £750 (or more these days from many gunsmiths). When you go to an F match see if you can lie down with each type, ideally dry fire or take a shot to see how you like the very different stock configurations. (I'm a fan of the Dolphin but not everybody is.) Also as Brillo says, not everybody cares for the Savage AccuTrigger even in its match version. (I get on fine with it, but it is a real Marmite component, and it has a habit of unadjusting itself over time / recoil inevitably needing readjustment mid match and producing misfires.) The Savage 12 PTA rifles work well, sometimes excpetionally well, but it is a clunky action and trigger compared to many, and I say that as one who has used PTAs in various form and calibres for many years and still own two rifles using this action/trigger which I'm very fond of. A common derogatory nickname for the breed on the US Accurate Shooter forum is 'the Salvage' amongst its detractors. So far as Savage factory competition rifle barrels go, a fair percenhtage shoot brilliantly once the very lengthy running-in period is over, far better than any factory component should; most shoot adequately for a competition rifle, ie still good but not exceptionally; a small minority are 'dogs' and never perform well. See if you can find a good secondhand Sightron 8-32X56 Series III scope, an excellent starter model for FTR, and what you save on the Vortex will let you buy a more expensive base rifle. And ......... good luck and shooting. Any new FTR shooter is welcome, especially another lady to add to the growing field of female 'Effers'.
  3. Laurie

    7mm saum and 284 load n165

    You should be able to get higher MVs than 2,850 from the SAUM especially with RS70 which is one of Nitrochemie's 'high-energy' grades and has the advanced 'EI' infused deterrents technology. Nodes generally occur at around 100-150 fps MV intervals, sometimes smaller intervals though, so you need to work up in small steps and see when you hit the next one at higher velocities, checking that pressures remain acceptable for your barrel and in your highest local temperature conditions.
  4. Laurie

    RS powders for heavy .223/6.5CM/.308 bullets

    Maybe, but I've never had any issues with RS52 in this regard. When I was loading 308 Palma brass with a trial lot of Nitrochemie EI-N130 (nicknamed Elcho-15) some years back that I was given by Nigel Cole-Hawkins for review in its pre Reload Swiss days, I intended to use it in quite a 'warm' load at the Scottish LR Championship meeting at Blair Athol a couple of weeks later in what promised to be very warm conditions. So to test its temperature sensitivity, I left an MTM 50-round box open on the front seat of the car for three hours straddling midday in full sun on a hot day at Diggle to see if I could detect any difference. I couldn't and the chronograph only gave a modest increase in MV. (EI-N130 is the works code for what is now retailed as RS52.) No powder, even the much vaunted ADI / Hodgdon 'Extremes' is completely temperature insensitive, it's more about being manageable in one's own conditions, and managing ammunition exposure on the firing point. I cringe when I see F-Open competitors shooting a 40 minute or so relay on Stickledown with those big MTM R100 type ammo boxes sitting in full sun and the lid thrown back. By the end of that relay, those rounds will be noticeably hot to the touch. The same competitors will (rightly) take great care to keep their ammo out of the rain on a wet day knowing what water droplets can do to pressures and precision, but ignore full sunlight which even in the UK can be hot. The only powder I've had real issues with is Re15 in my old 223 90gn F/TR load that was pushing pressures. I could watch primer cratering get progressively worse as ammo heated over the course of a hot day. An insulated sandwich bag was bought and by scrupulously keeping it and the ammo in shade, opening the box as little as possible and not keeping rounds in a hot chamber got around this, but only barely. RS52 seems to be the answer to this issue in the cartridge and combination as VarGet solved the temperature problems but lost 60 vital fps and never performed as well as the Alliant grade.
  5. Laurie

    Lovex powders - opinions

    Interesting that (re S&B primers). Yes, they're excellent caps. More though, the more I play around with primers myself and the more that I read of other people's experiences, the more convinced I become that matching the primer to cartridge / powder / load can be very important, sometimes the difference between a mediocre performance and a really good result. Unfortunately, there is no easy way or set of ground rules as to what will or won't work best. Some makes / models seem to have a wider tolerance than others - Rem 7 1/2BR, Magtech 7 1/2, maybe Murom SR223 in SR models, and CCI-BR2, Fed 210M, S&B, and Murom KVB-7 (or 7M magnum) in LR. I include the KVB-7M as in my old (PMC branded) lot at any rate, it is almost as 'mild' as the standard KVB-7 and in some cartridges gives slightly smaller ES / SDs with no change in group size.
  6. Laurie

    RS powders for heavy .223/6.5CM/.308 bullets

    RS52 would just about do the lot, although I'd seriously recommend slower burning RS62 for the 6.5 where '4350 class' powders are optimal. 52 suits the 223 and 308 applications very well though. Nitrocellulose only RS50 probably will too but will give lower MVs, in mitigation produce a bit less barrel wear.
  7. Laurie

    Lovex powders - opinions

    SO62 is an excellent choice for 308 with 150-190gn bullets. It used to be branded Accurate-4064 as it closely matches the performance and loads of IMR-4064. (Use Explosia's data though, not IMR's.) It will also work in 223, but is really better suited to mid-weight bullets there. (You don't say what weight you intend to use and that has a very large impact on powder choice.) The three 'ball' type powders DO-73.4/5/6 from fast to slow burning are well suited to the 223, the choice of grade dependant again on bullet weight. They usually give high MVs and in the right combination excellent precision. IME, they are 'dirty' though and leave a very hard burned on fouling on case-necks and shoulders that unless cleaned off immediately, immediately as in within minutes, after shooting (spray WD40 or Ballistol onto paper tissue or towelling and wipe the fouling off) is the devil to remove. SO60 (extruded /tubular) is a good choice for 223 in all but very heavy bullets, and although I've never tried it, rather faster burning extruded SO53 should be an excellent choice with lighter (40-55gn) bullets in the cartridge. It was designed by Explosia as a single-based extruded type for the 7.62X39mm and is an alternative to DO63 ball type.
  8. Laurie

    Reloading 7SAUM, with RS70

    I am frequently, but not this time!
  9. Laurie

    S070 vs RS62

    You could try both SO65 and SO70 in Creedmoor with 139/140gn bullets. QuickLOAD suggests that maximum usable loads are about 1-1.5gn apart; both give a near full case and MVs in the 2,700-2,750 fps range from a 24-inch barrel.
  10. Laurie

    S070 vs RS62

    Lovex's SO-series single-based extruded grades are excellent powders and can give very consistent results. Up to around 10 years ago, SO70 was better known as Accurate Arms-4350, but of the three 4350s on the market was the slowest by quite a margin. (Accurate 4350 is still around, but not here. It is made for Western Powders by General Dynamics in Canada the plant which manufactures most IMR grades.) Explosia's burning rate chart isn't very accurate unfortunately. It shows SO65 on the same line as Hodgdon VarGet which got people rather excited about it during the first great VarGet shortage. Excitement gave way to frustration as a VarGet substitute, it is not. It is slower burning, bulkier, and has less energy - well suited to 7mm-08, 7X57mm, 7X64mm and similar, but gave heavily compressed loads and low MVs in 308 Win. Even when accurately listed, as has been said many times before, burning rate is only one of several metrics that affect suitability and performance. IME, SO70 works well in applications that suit '4350-class' powders, so should be an alternative choice to RS62. However, it usually gives lower MVs than IMR or Hodgdon H4350, and as RS62 usually outperforms this pair, I'd expect a yet larger gap between it and the Lovex grade. With smaller cartridges like the Creedmoor, it'll also likely be limited by case capacity reaching compressed levels at modest pressures / MVs. (Nothing wrong with that if you don't need or want every last fps MV, of course.) In larger, roomier numbers such as 7X57mm, .30-06, and 6.5X55mm, it's well suited to them.
  11. Laurie

    Alpha munitions / Peterson brass

    Peterson is very good, .............. but how it compares to Lapua and Norma? We'll have to see on that one when people have got 10-20 firings in.. Their 6XC cases (in either primer form) and small primer brass for 243 and 260 are very new lines, so new that most Americans have yet to see any, so I doubt if it has come anywhere near reaching us yet. Bernie Montana of Extreme Performance in Lincs was importing / distributing Peterson brass and I assume he still is. 1967 Spud of UKV fame and Dauntsey Gun Company both retail Peterson cases that I know of, so talking to Mark (Spud) would be a sensible starting point. I've not heard of any Alpha brass here yet or anybody importing their products.
  12. Laurie

    .260Rem Load.

    I had very good results with 123 and 130gn bullets with N150. There is a downside though with this powder - pressures seem to peak rather quickly when you get to maximum. N160 is likely a bit (lot?) more tolerant. By coincidence, when I get back to shooting (convalescing after surgery right now) 260 is back on my 'play list' having had my old FN SPR rebarreled in it yet again, but this time in 'long throat' form for shooting 140s at around 2.95" COALs. I'll also use it to see how well Berger's impressive looking new 130gn 'Tactical AR-Hybrid' manages at magazine length and around 160- thou' jump. I'd more likely go 6.5 Creedmoor in SRP Brass form these days all other things being equal, but with the SPR being a b*gg*r for blanking SR primers and the cost of a firing pin turning / bolt bushing job being another £300 on top of the rebarrel, it was simply too expensive. There's nothing wrong with the old 260 anyway and plenty of good brass available for it.
  13. I was confusing the Rifleshooter test with a video piece from Johnny's Reloading Bench or some such that appeared some months back and claimed mis/hangfires with SRP Creedmoor brass with Viht N550 loads. It was almost certainly a temperature issue as this was during the winter. The methodology was crap because the tests involved different ambient temperatures for the differing case types as well as very small sample sizes. He thoroughly confused me too by apparently doing a flash-hole reaming job on the SRP brass using what was obviously a large diameter uniformer tool for the 2mm size hole. This left me wondering what size US made SRP Creeedmoor brass actually was. My memory may be letting me down again, but I think this was Peterson SRP Creedmoor - and this company assures customers its SRP cases have the correct 1.5mm flash-holes. This one is OK as far as it goes, but with large flash-hole SRP brass it's pretty pointless IMO. I like the Rifleshooter.com stuff - good down to earth nice builds without frills and they're genuinely pleased to get results under 1-MOA, and ecstatic to get half-MOA compared to the 'shoot quarter-MOA all day long if I do my stuff' pieces that have become the norm online it seems. A shame though about the images of the targets in this report - I tried making sense of them but to be honest gave up after a couple of minutes as I found them so hard to see. So far as actual MVs are concerned in the cartridge, nothing surprises me too much these days. Years back I had a Dr Geoff Kolbe designed and made chamber pressure measuring device for review - it used an accelerometer to measure recoil speeds and software that converted it into pressure. All you had to do apart from attaching the sensor was to input rifle all up weight, bullet and charge weight, and finally the bullet diameter, shoot a round or two and see what the machine said was being generated internally. Out of scientific interest I tried a standard Small Pistol primer in a pretty well mainstream 223 Rem loading alongside the SR magnum I normally used. The SP model gave higher MVs and according to the Dr Kolbe device. around 5,000 psi higher pressure. When it comes to cartridge ignition, nothing is as it seems ..... seemingly ☺️
  14. It needs a long action for repeater / magazine use with the 6.5-284 and you'd have to be happy the shorter / thinner body 308 rounds would still feed reliably. In a short-action, the 6.5-284 has to be a single-shot only option and depending on the action and size of its top-opening / port, you might have to remove the bolt from the action to unload a live round.
  15. To gain the benefits of SR priming, you also need the small (1.5mm / 0.059" dia.) flash-hole instead of the standard size (2mm /0.079" dia.). The Starline brass used in the tests has the large flash-hole in both versions. This alone almost certainly accounts for any odd findings on average MVs - the small flash-hole is reckoned to reduce MVs as much as, more likely more, than the primer size. I looked at this test a long time ago and although don't remember much about it now, do remember being distinctly unimpressed by its methodology and the numbers of cartridges fired. However, since IMHO there are no internal ballistics / accuracy benefits in using SRP Brass with a large size flash-hole compared to the standard LRP variety, I'd never buy any cases like this. The only potential benefit is that with a smaller pocket, the SRP version might last longer before pockets become slack and the cases have to be scrapped. There are a few cartridges around where you can get either primer size allied to the 2mm flash-hole - 7.62X39mm and 6.8mm Rem SPC being the two most common. When I had a 6.8 SPC AR-15 straight-pull, I did a side by side test between Remington (LRP) and Hornady (SRP) cases which fortuitously had very similar case capacities as measured using the water overflow method. With this small capacity case and powder charge - a great deal less than those of the Creedmoor, I expected to see the Remington variety produce significantly higher MVs, but there was nothing at all between them, likewise in ES and group sizes. It seems that if the powder is cleanly ignited, it's cleanly ignited when the only difference is the primer alone.(In the case of the 6.8, it seems Remington made a poor move in going for LRP with this smaller diameter case-head. The best, strongest, and longest lasting brass for the cartridge was Silver State Armory's SRP version when it was produced.)

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