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Laurie

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About Laurie

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  • 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

    A few Sierra match kings 180 grain HPBT to try

    At 0.247 G7, the 175 Scenar-L is barel;y better than the 1990s same weight Sierra MK, so seems on paper a poor or at least unadventurous choice. BC isn't verything though by a long shot. (Ouch! Awful pun!) There are too many over-long ridiculously stretched-nose designs around now with super-high BCs on paper that simply don't appear to perform consistently, or are so finicky about twist rates, barrel dimensions, MVs/pressures etc that hardly anybody can get them to work well. Just consider that Adam Bagnall took 2nd GB F/TR championship place this year shooting the 175 Scenar. Granted, Adam really is a fantastic handloader, shooter, and wind-reader, but the bullet seems to perform much better than its paper specification. Adam does admit to a fall-off between between 900 and 1,000 though where the lower BC likely does start to have a marked effect compared to the all-conquering Berger 200.20X. The trick with such lower BC bullets in 308 is threefold - 1) choose a design that is trans and even subsonic speed tolerant; 2) preferably drive it at speeds that will keep every bullet supersonic at maximum range, if possible gives another 100 fps above the speed of sound terminal verlocity ie 1,225 fps; 3) avoid an MV / BC combination that sees terminal MVs right on the sound barrier as some falling either side of it usually gives very poor results. Precision / small ES values too go almost without saying as essential prerequisites. The TR guys and girls are shooting the NRA GGG with the old 155 SMK (#2155) at a nominal 2,925 fps. On a summer's day at Bisley that'll only see 1K terminal velocities ~1,160 fps or not a lot (35 fps) of margin above the sound barrier, yet they perform brilliantly even allowing for the TR people shooting at a 2-MOA 5-ring. (The 1-MOA V-counts are remarkable these days in top matches!) Shoot the 175 Scenar-L at 2,750 fps and it'll be doing ~1,230 fps at the 1,000 target, 100 fps above the barrier. Adam in his specialised long-barrel F/TR rifle with hot loads in small-primer brass will start out faster (a lot faster I'd suspect!) but to get 2,750 MV in shorter barrels may take some of the same tricks, particularly use of small-primer brass at high pressures. Don't write the older 175gn SMK off either - a good and ballsitically tolerant design. The Scenar-Ls are so well made / consistent though, I believe they are worth a bit extra money over the SMKs.
  2. Laurie

    A few Sierra match kings 180 grain HPBT to try

    Calibre? (There are 180 MKs in 308 and 284.) If 30-cal, bear in mind this is a short/sharp-angle tail design and unsuited to long-range use in 308 Win.
  3. Laurie

    Bullet seating, are we doing it wrong?

    I see what Fox Tales is getting at, and it's inherently correct - but the claimed effect is exaggerated. 10 thou' difference in case-head to shoulder datum points between new brass and fireformed then properly resized fired cases is huge, at least in modern rimless commercial cartridges and firearms. (Early 20th century rimmed military designs such as 303 and 7.62X54R as werll as belted magnums deliberately ran with large amounts of case to chamber clearance at the shoulder, but they don't headspace on this point.) 10 thou' clearance is in effect 'excess headspace'. it means the first fireforming use risks thinning the case walls just above the web. Oddly enough, I've just seen something similar with new brass for a particular cartridge desdigned mainly for use in AR type rifles and it caused me some vexation and head scratching when shot in a turnbolt rifle until I twigged what was going on during fireforming. The difference between a good quality new case and one fired / resized in a decent chamber is much smaller usually, under 5 thou' and often at around 3. Of course, the modified case used in the OAL gauge tool might produce such a variation. This tool is a boon, but it's nothing like as precise as many believe - hence the very sound advice that unless very precise measuring methods are employed, jump shouldn't be set at 5 thou' or less and 10 is a lot better. This avoids the possibility of an over-measurement producing a COAL that is right on the lands but only just - not in itself necessarily undesirable, but what is to be avoided is the situation where small variances in bullet ogive positions may see one round with its bullet a thou' or two 'in' and the next a similar amount 'out', a set-up that usually produces fliers.
  4. We'd better not tell them then. A bit of the Nelson blind eye touch maybe. Serious point though - it'll leave many 303 shooting MoD range users wondering if they can take their pieces of British and British Empire history to an MoD range. When people make 'technical' regulations, sometimes common sense is allowed to be applied to their interpretation, but that can't be taken for granted.
  5. A bit hard on 7.92 Mauser shooters in historic arms rifles. Does it affect 303 too (it is a larger calibre even if only just than 7.62/308)? If so the MoD has banned the cartridge most of its ranges were built for and its own regular and reserve troops used for 70 years, the cadets a few more years longer.
  6. The basic Russian Murom LR primer works very well in the 284 Bruce - that's the KVB-7. I've also used the so-called Magnum version of this model successfully in 284 and Shehane, the KVB-7M. The 7 and even the 7M are very 'mild' models and that's generally what works best in this cartridge even with charge weights in the mid to high 50s grains. Before anything else though, try the CCI-BR2s you have. This is a mild and very consistent model. Avoid the Rem 9 1/2 and 9 1/2M, both very 'hot', also the Federal 215 LR magnum and its 215M 'match' version. Exceptionally 'hot' and in a cartridge the size of the 284 tend to produce large MV spreads. (Might suit a mid winter 600 fixture with temps at minus 10 though! ) I'm assuming you're using a realtively easy to ignite powder such as Viht N165 or the now lost H4831'shortcut'.
  7. Laurie

    6.5 creedmoor and RS62 temperatures

    Yes, I have Hunter and have used it in a few things over the last few years. It'll be one of those tried in the 260. It flows too well for the RCBS Chargemaster even with David, Shooting Shed, Bonwick's thingie used, so it (and other Ramshots) sees my old Hornady 'Competition' volumetric measure recalled to use. In this tool, the Ramshot grades produce remarkably consistent weights.
  8. Laurie

    6.5 creedmoor and RS62 temperatures

    I agree RS52 is very different to N550, but VarmLR says he was using RS62, very similar burn rate to the 4350s, N150/550, and N204 but single-based of course. It's interesting (and encouraging) that you find N204 so close to H4350. I intend to do some comparative tests in 260 Rem next winter looking for alternatives to IMR and Hodgdon H4350. RS62, Norma N204 and URP, Viht N550, Alliant Re16, and Lovex SO65 look the most likely possibilities. In the US, Re16 is being quoted as a very close match to H4350, very temperature tolerant - allegedly as good as the best of the Hodgdon / ADI 'Extreme' grades, and giving somewhat higher MVs than H4350 in suitable cartridges. It is of course double-based like all Alliant and Norma powders and I haven't seen a % value anywhere as yet, so may be hard on barrels if loaded up fully. Like the Norma grades, Re16 is manufactured by Bofors in Sweden, but has Bofors / Alliant's new 'TZ' treatment technology to reduce temperature change effects. It is finally available here and I've bought a couple of pounds to try. Norma powders have always had a reputation for being very temperature affected. I certainly found that with Alliant Re15 (same thing as Norma 203-B) in 223 some years ago even in our climate. Whether the newer grades such as URP are better I don't know, likewise whether Bofors / Norma are respecifying existing grades or improvements are restricted to the new ones only available under the Alliant brand name with 'TZ' (Re16 and 23 so far). Even if they've not said so, most propellant manufacturers are looking to reduce the temperature sensitivity of their ranges. Vihtavuori is allegedly in the process of doing so for all of its rifle powders whether N100 or 500 series. So far the only one they're admitting to is the new N565, but rumours say other older grades have been 'done' too. The company is keeping very tight on this and will only announce it if and when the entire range has been modified. Whether any such change affects other characteristics is an interesting (and important) question given that Viht has a reputation for lot to lot consistency so no need until now to check if a new lot needs any load adjustment. Returning to N204 it is one of the lower nitroglycerin content Norma grades at 4.5% by weight, so should give a small performance boost but without significant extra wear and tear. The new(ish) URP is one of the three 'hottest' Bofors/Norma grades at 10.5% alongside 217 and slightly less than MRP's 11.5%. URP is stated by Norma to be slightly faster burning than 204, and its applications are similar looking at Norma's No.2 manual published last year. In some applications, it gives little or no MV increase over 204 at Norma's listed maximum loads; in others, MV is significantly higher. Lovex SO70 (being the old Accurate-4350) would seem the most likely 4350 alternative from that source, but was always known to be the slowest burning of the 4350 trio. I've never found it as satisfactory as the IMR and H versions perhaps partly for this reason. SO65 though looks interesting. Explosia's burn rate chart shows it on the same horizontal line as H. VarGet which is clearly nonsence. It makes a very poor VarGet replacement in cartridges like 308 Win and superficial digging in Explosia's Lovex loads data tables shows it's much more at home in higher case capacity to bore ratio cartridges like 7X64 and 7X57mm. I've used it for some time in a long-throat 7mm-08 F-Open rifle with very good results indeed with the 150gn Lapua Scenar-L as a short-distance load. I note with some interest that Shooters World in the US which is now distributing Lovex powders under US-orientated SW brand names (SO65 becomes 'SW Long Rifle' for instance) raves about it for use in the 6.5mm Creedmoor .... https://shootersworldpowder.com/long-rifle/ .......... the classic H4350 application. One problem is that Explosia's own loads data omits many cartridges people here might want to try it in, 260 Rem and 6.5mm Creedmoor for instance. Shooters World is building up its own pressure-tested data-sets https://shootersworldpowder.com/wp-content/uploads/shooters-world-manual.pdf which fills some gaps. There's a good selection of Creedmoor load combinations.
  9. Laurie

    6.5 creedmoor and RS62 temperatures

    Yes, all Alliant 'Reloder' series rifle powders are 'double-based' Most come from the Bofors, Karlskoga, Sweden plant and a smaller number from Nitrochemie in Switzerland (ie the 'Reload Swiss' people). This goes back to a US government pre-WW1 anti-trust ruling that split the USA's single propellant / explosives combine up. In smallarms propellants, all single-based products and manufacturing facilities went to what later became IMR and all double-based equivalents went a new outfit the Hercules Powder Co. Alliant ATK eventually bought this side of the business and rebranded its products 'Alliant'. There is no legal requirement these days (at least AFAIK) for Alliant grades to be in this form, but the company has stuck with it. Likewise, all Norma powders come from Karlskoga and are also double-based. Norma quotes the nitroglycerin %s and they range from low single figures to barerly into double figures. (Viht N500 series are generally considerably higher.) All of the new IMR 'Enduron' powders are also 'double-based'. There is a tendency it seems for new additions / results of recent R&D to have at least some nitroglycerin in the recipe. I imagine this is partly about performance, but also all the other things that prpopellants are expected to do nowadays from accepting temperature stability to copper fouling reducing additives.
  10. Laurie

    6.5 creedmoor and RS62 temperatures

    I've got a couple of pounds of Alliant Re16, yet to try it - but on paper it looks a good option in this bracket. This is one of the new Swedish (Bofors) made Alliant grades with the company's 'TZ' temperature technology and is claimed to be as good as H4350, possibly better in this respect. As to applications and burning speed, it's very close to H4350 but can usually produce higher MVs if loaded to maximum levels. See: http://bulletin.accurateshooter.com/?s=Alliant+Reloder+16&submit=Search Norma (all of whose powders are made by Bofors) appears with a couple of additions such as URP to be offering an unchanged range from say 20 years ago without any updates, and this seems rather unlikely given the way all propellant manufacturers have ugraded their products in recent years. So, it may be that today's Norma N204 and Alliant Re16 are one and the same thing. (I have some N204 on the way too and will be able to compare their grain structure, density, and performance.) Right now, the reintroduced Norma grades are considerably cheaper in the UK than Alliant powders, worth considering by British forum members. (Re15 and Norma 203-B are one and the same thing for instance.)
  11. Laurie

    Pierced primer! Trip to the gunsmith?

    The original model SR primers were designed for the low-pressure .22 Hornet in the 1930s. Many such rifles had weak firing mechanisms as they were converted rimfires or built on elderly small single-shot Martini or falling-block actions. So primer cups were made of a soft brass alloy and are 0.020" thick to ensure reliable ignition and they were plenty strong enough for 22H pressures and the similar cartridges that followed it like the Bee. When Remington introduced the .222 Rem cartridge with its 52,000 psi peak pressure in 1950, the company decided its model 6 1/2 primer was inadequate for these pressures, so introduced the model 7 1/2 'Magnum' primer for this cartridge. It had the same explosive pellet as the 6 1/2 so the 'magnum' bit was solely the increase in cup thickness from 0.020" to 0.025" and maybe a bit tougher alloy. (It has since been replaced by the 7 1/2BR model originally introduced for the 17 Rem which needed a slightly 'hotter' recipe.) The 'soft' / weak models are: CCI-400 Rem 6 1/2 BR Murom KVB-223 / older copper coloured PMC SR Winchester WSR (0.021" cup thickness) - but only more recent brass colour WSRs, older silver ones were thicker / tougher. Federal 205s and 205Ms are nominally 0.225" thickness. Everything else is 0.025" The thin / weak models shouldn't be used in higher pressure cartridges such as 223 with full loadings. For decades Remington printed this on its 6 1/2 packaging but dropped it in recent years for some reason. So the OP has fired thousands of his loads with a too-weak primer and had no problems no doubt due to a mild load / pressures. Fair enough, but there will be little margin and as another post points out, there can be the occasional faulty or thinner example or production lot. Personally, I know what my choice of primer would be for 223 - always a thicker model - but in this case, I probably wouldn't worry ............ until or if it happens again.
  12. Why are you reading and commenting on a topic in the Forum's Handloading section then?
  13. Laurie

    Best reloading manual

    They can vary a lot - I just saw 3gn difference in a maximum load for a 6.5mm Grendel combination, ands believe me that is a huge amount in this tiny cartridge. In this case, much of that may be that US SAAMI MAP is 50,000 psi and European CIP is around 8,000 psi higher. 5-10% variances between manuals aren't unusual and can depend on make of brass (different internal capacities), primer model, powder lot variances and the test barrel internal dimensions. The components (case + primer) differences can be great enough to make a major change and that's why most manuals say somewhere in the introductory text section that the printed loads apply only to combinations using the specified items. Occasionally, a manual says that the loads apply to that make of case and that only. Speer does that for 243 Win saying that there is an unusually wide spread of case capacities in this cartridge and that its loads are specifically for Winchester brass only and no others. Sierra tends to use Federal cases whenever available for the cartridge and in contrast IME these are usually on the heavy / low capacity side increasing pressures / reducing max loads. Also, of course whether the supplier is super-cautious or wants to impress the manual owner with maximum possible MVs. I like it when pressures are shown as this gives some indication on this issue, also whether as sometimes applies a maximum load is determined by how much powder the case holds with the particular bullet at that COAL not the PMax generated. Then there are 'dodgy' cartridges, usually elderly originally military such as 6.5X55, 7X57mm, 7.5X55mm Swiss etc where the testers / compilers have to decide whether to provide max loadings for modern rifles, for SAAMI which is often lower, or for some yet lower PMax in case the shooter has the oldest, weakest rifle model that the cartridge was ever chambered in.
  14. Laurie

    NRA RCO Handloading Rule

    I'm intrigued by a spot-check on 6.5X47L as it's pretty difficult to get outside of the MoD envelope at least with anything other than light varmint bullets. 6X47 or various other 6mm wildcats could easily be an MV issue though. Everybody 'thinks' HME / ME on this topic, but remember there is an MV ceiling too that in effect rules out 204 Ruger, 22-250 Rem and many SAAMI / CIP sixes with anything less than the heavier match bullets in fast-twist barrels. https://nra.org.uk/nra-bisley/ranges/latest-range-information/range-regulations/ 1,000 m/s = 3,280 fps
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