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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

    N 150 versus N 550

    You can wear barrels out pretty quickly with N150 too if pressures are high enough. Some of the hot loads for 185/200gn Bergers with N150 in Palma brass only give a 2,000-2,500 round barrel life in 308 Win. Steve D by comparison claims he gets around 3,500 with his N550 load, presumably running at lower pressures. However, these are all small samples and barrel steel / rifling type affects barrel life significantly too. I have a suspicion that if pressures are kept to moderate levels, most of the N500 series won't burn out barrels particualrly quickly. An exception may be N540 as it has a near 40% nitroglycerin content by weight - same as arsenal Cordite .303 British Mk.7. Powders with some nitroglycerin are almost becoming the norm now - the new IMR Endurons all have some and all Alliant powders whether from Nitrochemie, Bofors or General Dynamics St. Marks have this ingredient. All ball types are double-based, likewise Norma extruded powders. I bought a secondhand Musgrave TR 308 many years back with a nearly new Maddco stainless barrel on it and developed a mild 155gn SMK / Alliant Re15 load for it, shot the rifle for three or four seasons and sold it. I meet the buyer regularly who still owns this rifle maybe 15 years on, and he still uses that Re15 load. The barrel round count must be astronomic by now, but he says it still shoots as well as he can, if not better.
  2. Laurie

    N 150 versus N 550

    That's a good (and difficult) question Alan. Viht itself says the N550s are more temperature stable than N100s. Conventional wisdom says that it should be the other way round! Search on forums etc and you find what are in effect opinions, not facts - and they are contradictory from US users claiming everything from excellent to terrible. All I can say about N550 is that it appears to be a bit harder to ignite than N150 in cold weather conditions. (Lapua small primer 308 'Palma' which is ignition / temperature sensitive and N550 starts to lose MV / increase SDs at higher temperatures than N150 this being on or just above freezing.) Steve Donaldson, one of the UK's top F/TR shooters as was although he's now largely dropped out of League levels, has used Palma brass, Berger 210gn BT, and a stiff load of N550 for nearly 2,700 fps from a 34-inch barrel for many years with great results. Back in 2013, he dropped out out of the GB F/TR team and went to the FCWC in Raton, New Mexico as a privateer. Not being subject to team rules, he shot every competition and practice he could over the two weeks and put an enormous round count in - his rifle was borrowed by fellow Rutland team members too. With locally sourced primers and fresh N550, he used his UK load throughout without any charge weight reduction - and did very well in the US National F-Class Championships and then the World Championships. At ~7,500 ft ASL in a semi-desert climate and in a local heatwave temperatures went from cool first thing to very hot by our standards peaking in the mid to high 90s F in the shade by late afternoon on some days in week one, a little cooler (low 90s) in week two. Steve assured me his UK load worked fine throughout and he'd no pressure issues at any time. I believe many 'Match Rifle' competitors use N550 too with 200-230gn bullets in Palma brass and these lads and lasses go off to shoot MR in Australia in sometimes brutal temperatures as an NRA team. Vihtavuori has quietly added anti copper fouling additives to their powders recently and says it will be reformulating most (everything?) in its range to be temperature insensitive in the near future. I'm not surprised - it's becoming increasingly difficult to sell propellants into both sport and military markets these days if they have the reputation of being temperature affected. Hodgdon / ADI has been in the lead for years with the Extreme range of extruded powders, but now IMR (General Dynamics, Valleyfield, Ontario) is adding new 'Enduron' grades which although not quite as good as ADI is still very good indeed, and Alliant ATK's recent additions from Bofors, Karlshoga, Sweden such as Re16 have a new 'TZ' technology claimed to rival the Hodgdon/ADI 'Extreme'. Certainly American users are raving about them in every respect. (We don't get any here as yet - I hope that is going to change.)
  3. Laurie

    N 150 versus N 550

    Viht shows its N100 powders and their N500 equivalents with the same burning rates ........... but they're not. The high-energy versions are slower burning, sometimes significantly so. QuickLOAD lists N530 as slower than N140 never mind N130 through N135 and N560 as being slower burning than N165. Changes in quickness in themselves affect the charge weights that produce peak pressures.
  4. Laurie

    6.5 Creedmoor brass

    Good to know. The 'problem' with SRP brass and 40gn + charges is one of potential powder sensitivity. My experience is with the slightly larger case and charge weight 308 Win 'Palma', another two to six grains powder. In one case (Hodgdon CFE223 'spherical') I got 48 hangfires and two complete misfires at normal UK spring temperatures from 50 rounds; in others (Viht N140 particularly) performance began to be affected below around 3 or 4-deg C. Yet while N140 went to pieces and CFE apparently doesn't work at all in any temperature, N150 works right down to freezing (at least) and H414 'spherical' (made in the same factory as CFE) actually gave higher MVs and smaller ES than in Lapua LRP brass at just above freezing. One of the American 243 Win long-range shooters assured me on another forum that Peterson Cartridge Co. SRP 243 brass was hopeless with his favourite compressed load of coarse-grain / slow burning Hodgdon H1000 in US summer temperatures - 200 fps MV reduction and huge ES values. So, whilst the range user is pretty safe with most primer / powder combinations in the small primer / small flash-hole combination, there is a chance even in our climate that the sporting user could be caught out on particularly cold days and finding your rifle shoots several inches low at a couple of hundred yards range after a long Scottish Highland glen stalk on a red deer isn't fun for either stalker or deer I'd imagine. Just to complicate matters, it seems the small 1.5mm flash-hole is as much a cause of these behaviours as the primer size and brisance, maybe even more so, and it seems some of the new US made SRP versions have stuck to the large (2mm) flash-hole. Starline SRP brass is in this form inlcuding its Creedmoor it seems.
  5. Laurie

    6.5 Creedmoor brass

    As a deer rifle, you may be better using LRP brass. The SRP variety struggles with some powders, but more to the point, may see significant velocity drops in very cold conditions or even hang/misfires. The other potential downside with SRP in high-pressure cartridges is that the small primer is much more prone to severe extrusion back around the firing pin than the large variety. This can manifest itself as 'cratering' or in extreme cases 'blanking' where a disc of primer cup brass detaches and is blown back into the bolt. This is a firing pin tip diameter + pin tip fit in the bolt-face issue. Some rifles are prone to it. (Mik Mak of Dolphin Gun Co. tells me he has done the firing pin reduction / bolt bushing job on over 30 AI rifles - they were fine with 308 Win or 260 Rem etc, but struggled with a rebarrel to 6.5X47mm Lapua and its small primer. I have an FN SPR Winchester 70 based tactical rifle that is hopeless with SR brass, so I've kept as a 260 as I'd only switch to Creedmoor if I could use the SRP variants - entirely for range use in my case.) Note too, this will become a bit more of an issue over time. Peterson Cartridge is offering 243 Win, 260 Rem now in both varieties alongside Creedmoor and 308. We'll maybe see some confusion as these get here and are bought by those unaware of the differences and implications. 6.5 Grendel comes in various forms - at least three primer size / flash-hole diameter variations. I'm sure we're going to see more of these new versions of other cartridges too from Lapua, Peterson and some of the other young US case manafurers.
  6. Laurie

    Alternatives to QuickLoad

    Nor does QuickLOAD - there is no primer input so you cannot determine any effects of using SRP brass v LRP other than that calculated pressures / MVs will normally be overstated. IME with SRP brass, it is not possible to make sensible predictions anyway as it depends very much on the bullet + powder combination. In 308 Win 'Palma' brass, I've seen the SRP effect ranging from the equivalent of around half-grain to 1.4gn charge weight reduction compared to the same combination in Lapua LRP brass with the same capacity. QL is invaluable in other respects of course, such as where the combination contemplated cannot be found anywhere else in manufacturers' published or online datasets. Where possible though it is very important indeed to crosscheck QL results against published data.
  7. 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.
  8. 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'.
  9. 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.
  10. 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.
  11. 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.
  12. 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.
  13. 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.
  14. Laurie

    Reloading 7SAUM, with RS70

    I am frequently, but not this time!
  15. 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.

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