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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

    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.
  2. 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.
  3. 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.
  4. 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.
  5. 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 ☺️
  6. 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.
  7. 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.)
  8. Laurie

    6,5mm Creedmore or 6,5x47L for F Open?

    Lapua alone loads factory 6.5X47L - four Scenar match loads and one Naturalis deer load. http://www.lapua.com/en/ammunition/calibers/65x47-lapua Unusually the small to mid-size US ammunition companies which produce boutique versions of 260 Rem and 6.5-284 largely or entirely ignore the cartridge too. The near complete absence of adoption by mainstream rifle and ammunition manufacturers contrasts with the Creedmoor situation where there is a Gadarene rush onto a near runaway bandwagon and suggests that the 6.5X47L is and will remain a specialist number mostly used by shooters who handloader
  9. Laurie

    New .243 load help

    I'd be a little wary with QuickLOAD. Having run several combinations and then compared them to published data in reloading manuals, some QL results are close, but in some combinations an apparently suitable QL result producing an estimated 57 or 58,000 psi PMax may be as much as three grains higher than the loading manuals' maximum figure - a lot in this cartridge to put it mildly. One possible reason for this is that there is apparently a great deal of variance in 243 brass capacity. The Speer manual uses Winchester cases and states in a general warning on the cartridge that its staff found unusually large variances between case makes and stresses that its loads apply to this one make of brass only and should not be transferred to any other. In the loads that I will work up in due course, I'm using several makes of case, but so far have no fireformed examples so have been using QuickLOAD's default capacity. Where there is a significant discrepancy with loads from manuals, I've used the latter and will see in due course which is closer to reality based on Labradar MV results.
  10. Laurie

    .308 Target rounds

    I'm not saying it's unsuitable, rather sub-optimal as it was designed for a lower bullet weight. But it's still a free country (just) and you're welcome to use any powder you fancy in the cartridge as long as it's safe, and N135 is safe enough as long as the manufacturer's loadings are adhered to. You won't find any serious long-range 308 shooting competitors using it though.
  11. Laurie

    243 powder

    Not that I've seen. Sierra Bullets (which has for years collaborated closely with the US Army) mentioned it in a loading manual many years back. The US Army did its research in the aftermath of introducing the 7.62X51 round / M14 rifle and deciding on a policy of ball powders only for non-specialist 7.62 types, so I'd assume it dates from the late 50s or maybe early 60s. Almost everything that the US Government and its agencies researches is available somewhere online unless it is 'classified', .... but finding it. With so many developments in propellants in recent years, it's dubious how much one would learn now anyway from 50 + year old research. People shouldn't get too worked up over 'double-base'. Most recent introductions have nitroglycerin in the mix somewhere - all of the new IMR 'Endurons' for instance; every Alliant 'Reloder' grade; all ball types. Viht N100 series, RS 30/50/62, and Lovex SO extruded grades are the only true single-based types left to us now. However, Viht N500 series aside and some of the older grades, the norm is 3-10% nitroglycerin content by weight and if loads are sensible, barrel life appears as good with these grades as with anything else. I bought a secondhand low round count Musgrave 7.62 TR rifle with a Maddco stainless barrel maybe 25 years ago, shot it regularly in TR matches all season for some five years and sold it to a fellow club member who still has it. The load was (and is) the old Sierra 155 MK and Alliant Re15. I passed the load on and the new owner still uses it. That barrel is still going well today, and the round count must be really something. As we never shot beyond 600 yards and more often than not at 300 only, the loading was mild. Some Viht N500s have very high nitroglycerin levels - N540 was reported as 45% on its introduction many moons ago and I assume it's still very high. What does kill barrels fast is the combination of a high-energy mix allied to advanced deterrents early burn modifying technology, in particular RS's 'EI' grades (RS 40/52/60/70/80 and some Alliant powders supplied by Nitrochemie). They will give a step increase in performance but the extension of the peak burning pressure and heat period increases the stress on the chamber throat rear end of the barrel. Don't load them up to peak pressures and performance and they should be fine. (I have an FTR rifle with a Broughton 5-groove that has had a lot of RS52 down it and its performance is holding up very well.) With the 243 being a known barrel burner, there is a good case though for the high round-count user to choose powders carefully. Viht N160 and N165 are obvious candidates for the heavier bullets. (John Whidden keeps winning US national championships with the 'straight 243' 105 Hybrids and N160 too - ~1,300 rounds barrel accuracy life he says and remember American prone competitors string-shoot, so rounds will go downrange as fast as the target is marked and a lot faster than our TR or F-Class.) For ball powder lovers, I imagine the Ramshots will give acceptable if not in fact very good life if pressures are sensible.
  12. Laurie

    .308 Target rounds

    Where have you seen Vihtavuori recommend N135 in this application? That a powder grade is quoted in loading tables means it can be used, but it may or may not be optimal. N135 is the canister version of Viht's bulk propellant for standard 7.62X51mm NATO ball rounds and is optimal for that cartridge in NATO STANAG spec barrels and chambers - ie a slightly undersize (compared to SAAMI .30's 0.300/0.3080" bore/groove ) bullet loaded into a heavy case and within the 143-146gn weight range. It is usable with a heavier 155gn bullet - but that is neither optimal nor recommended. As a short-range load it'll be fine and its slightly lower loads please the penny pinchers. One just needs to look at Viht's 308 Win data for the 155gn Sierra MK and the maximum loads shown for N100-series powders to see the internal ballistics relationships: N135 Max load gives 2,674 fps N140 Max load gives 2,712 fps N150 Max load gives 2,790 fps For bullet weights up to 150gn N135 generally gives higher MVs than N140, its faster burning rate better suited to this application. From and including 155gn, this is reversed and Viht doesn't show any data for N135 for bullets heavier than 185gn, and in this case for one bullet only out of several covered.
  13. See: http://bulletin.accurateshooter.com/2018/05/good-news-for-gunsmiths-major-itar-changes-coming/#comments The detail isn't available yet, but it looks like many of the things we buy from the USA may be exempted. If so, good news.
  14. Insofar as SR primers go, there is NO relationship between so-called 'magnum' primers and 'magnum' (hotter) performance. Magnum SR (and BR types) primers have thicker cups but often have the same pellet as the standard grade inside. Some individual models (including non-magnums) are slightly warmer than others. See first conclusion (commentary on Table 1) in: http://www.targetshooter.co.uk/?p=2662 What I increasingly see is the difference SR primers can make to performance - not in MVs but in matching the rest of the load and changing group sizes. This has two results. First some experimentation with primers may be necessary during load development to get best results, and 2) once you've settled on a primer model stick with it. Changing primer (sometimes even buying a new lot of an existing one) often requires the load to be fine-tuned again.
  15. Laurie

    New Brass prep and new load to develop

    I neck-size first then use the body die - no particular reasoning in this order and it'd likely give the same results if reversed. The Collet die doesn't need any case-lube at all, so my cases are decapped and cleaned first then neck-sized. They need lubing for body-die full-length sizing of course, this action often done at a later stage nearer to priming charging and bullet seating etc. For Forster Bushing-Bump sizing, I've always used the merest smear of Imperial Wax Sizing lube on the neck and shoulder. Whilst the Collet type presses inwards onto a now static neck, I don't like the idea of any unlubed sliding contact between a bushing and the neck. Whether the small amount of lube on the shoulder is really required is debatable, but I've found I get very consistent shoulder set-back between cases using this method. Lightly smeared finger / thumb application and small amounts of lube involved over a limited area make for very quick and easy application / wiping it off afterwards.

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