scrumbag
Well-Known Member
30 or 32” barrels, bullet hanging right out the front needing a custom throat
RS 62 vs RS60
- Thread starter gixer1
- Start date
30 or 32” barrels, bullet hanging right out the front needing a custom throat
Cambridge Pimpernel
Active Member
Correct - throats chambered well out. my OAL's are c.3.300
Cambridge Pimpernel
Active Member
Never read as sarcasm!
The loads are compressed - c 49gr of RS60. It is a very good combo. We generally shoot sub minute elevations at 1000yds, and 1.5mins at 1200. The wind though is a different matter entirely!I have wondered what you MR guys and girls were running these days, and if RS60 featured in it. Now I know - thank you.
2,000 round or so barrel life isn't bad at all for this combination / performance. It's no worse than many 308 F/TR shooters are getting.
When I was shooting F/TR some years back in the early days of heavy bullets and Re17 was then new on the market, I did try it. MVs were impressive, but I never achieved the one third-MOA or smaller groups that this discipline needs at top level. Most others who tried it reported the same thing.
scrumbag
Well-Known Member
I think this is a very valid point and @Cambridge Pimpernel is right to caution chasing the velocities the MR guys get with those bullet weights.
With a 215 gr Berger Hybrid and a COAL of 2.800 using GRT standard defaults (Case volume 56.3 gr of H2O, 600mm barrel) gives a combustion chamber of 41.70gr and an MV of 2,465 with a compressed load (106%) of 43.0gr of RS60.
If you set the COAL at 3.300 you have a combustion chamber of ~51.0 gr H2O. Up the charge to 49gr of of RS60 and you get an MV of 2,550 fps.
Stick a 34" barrel on that and you are over 2,750 fps.
Interesting what happens with that set if if you chamber a round and have to unload it though...
I have shot little bits of MR (Any rifle)
Use a 26" barrel, 1:8.2 twist 7x64 with 180gr bullets and RS 70 seated within CIP COAL (Load isn't even compressed)
The conscensus when chatting to someone on the GB Match rifle team was:
My barrel is a bit short
My bullets are a bit light
My bullets are travelling a bit slowly
Could I get more powder in?
(Also, you could argue that the way to confuse a Bisley RO is to shoot with a Moderator)
@Cambridge Pimpernel is also correct that it isn't the elevation that gets you, it's the wind.
@ 1,200 yds using a 215 Berger @ 2,800fps you'll have ~36MOA of come up from 100 yds. With a 10 MPH wind at 90 degrees to shot you'll have 7.5MOA of wind drift (95 inches). Wind moves from 3 o clock to 2 o clock and you are suddenly at 6.3MOA. (This is calculated, these values are probably understating the actual correction)
As a side note, the v-bull, most central scoring ring at that distance is 14.4" in diameter. Or 1.1MOA and the black aiming mark is 3.8MOA)
You can shoot Anyrifle with your hunting rifle, it's a challenge. I do it, come have a go.
Available: - Anyone fancy trying some fun long range shooting at Bisley? NOW MUCH EASIER THAN BEFORE!
Hi folks, The NRA has made it easier to shoot in the Imperial shooting competition this year by expanding the “Any Rifle” competitions meaning you don’t need some weirdly configured, only good for targets rifle in .308W to shoot there – and as a pleasant surprise, SOME OF THESE EVENTS ARE ON A...
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Scrummy
Cambridge Pimpernel
Active Member
Yep. Shocker. Some do load into the lands, which can reduce the standard deviation of the load and improve accuracy of a load, but for the very reason you point out and increased pressures, I don’t. Because neck tension is generally light, unchamber the round, and you risk the bullet come out of the case, powder granules going everywhere incl. into the trigger mechanism, and at that point you’re done. It’s surprising how one tiny granule can seize an entire action. Better load off the lands with a small jump, and not risk it.Interesting what happens with that set if if you chamber a round and have to unload it though...
Cambridge Pimpernel
Active Member
And this. This weekend at 1200yds, the wind was gusting, and with no perceptible change in wind strength, 215gr bullets were deviating by 4-5mins (c 4ft) either side of centre depending on whether you caught a pocket or a puff. It is why I’m not a particular fan of long range hunting, unless the pot absolutely requires it. Fine for paper, but stalking, where bullets are usually lighter and you don’t have wind flag indicators, the risk of wounding is high, and in my mind, not fair on the animal. And by long range I mean anything over 300yds.
I’ve only done it once, paced at 296yds with a .243, with a 6 power scope and a c120gr bullet. I was aiming at what was a tiny target in the scope, c. 9 inches over its back, and horizontally somewhere over its nose. The only reason I was arrogant enough to try it was that I was on my game, having just come c4th in the annual national MR comp, I had a rock steady position, and reckoned I could translate the wind call from 1000yds to 300, accounting for difference in bullet weight and speed vs my then usual 190gr load, in my head, using the mirage that I could see. I got very lucky and put the bullet smack in the right place. My father summed it up perfectly that evening when I recounted what had happened with a grin on my face like the cheshire cat. “You do realise that morally, the Stag won?” He was right. We hadn’t been able to get close enough to fire a perfectly aimed shot that would guarantee killing it cleanly. We had taken a chance that even for me, as a pretty competent shot, was risky and by sheer good luck the gamble had paid off. My grin disappeared, my waggy tail slunk between my legs, and the lesson was taken on board. That was approaching 20 years ago, I’ve never done it again since.
scrumbag
Well-Known Member
@Cambridge Pimpernel was that the English VIII meeting?
I shot the LMRA on Bank Holiday Monday and 1,200 yds was REALLY interesting wind holds...
I shot the LMRA on Bank Holiday Monday and 1,200 yds was REALLY interesting wind holds...
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C P ,,,,What twist was the 243 barrel and what was the bullet make & construction that you used please?
Ian
Ian
Cambridge Pimpernel
Active Member
I would love to help - but alas it was 20 yrs ago, and an estate rifle so I can’t say - but I would assume “standard”. I think the ammo was norma, but i may be wrong. I remember looking at the side of the ammo box to get the ballistic data. As I say, I wouldn’t recommend emulating the exercise!
Hmm... I would take issue with the implication that hammer forged CM barrels will outlast SS barrels.
First off, part of the barrel wear process in CM barrels is the nitriding of the surface of the steel by the hot, nitrogen rich gasses. This creates a hard, but brittle surface to the steel, which cracks and flakes off due to thermal stresses of subsequent shots. If you look at the list of perfect steels for the nitriding process, chrome moly steel sits there at the top of the list. Stainless steel for rifle barrels was developed by Crucible in the United States to mitigate this problem. Type 416R stainless steel is not easily nitrided and so has extended barrel life.
On hammer forged CM barrels, I have lost count of the number of SAKO and Tikka barrels we replaced at Border Barrels, as they were essentially 'worn out' after a few hundred rounds. The hammer forging process produced a work hardened skin on the surface of the bore, which was brittle and flaked away from the softer steel underneath it. This took place all down the barrel, but primarily at the back end where temperatures and pressures were higher. I do not recall this happening with the hammered Enfield barrels, but that was not a CM steel like EN19 or EN24
One steel we did find gave extended barrel life was the steel Lothar Walther use in their barrels. In a trial we did with Radway Green, we made some test barrels which used the Lothar Walther steel and, shooting 5.56 Nato ammo, they lasted twice as long as barrels made with 416R stainless. But that Lothar Walther steel is almost a true stainless and very difficult to machine. There is no point in looking at it unless you have carbide tooling and reamers.
welshwarrior
Well-Known Member
@Cambridge Pimpernel you MR boys are a bit odd but the load development is very interesting and certainly offers benefits over issued 155 grain with all its issues. At least when your extractors break or dislodged it’s your fault!
Hmmm! There may be some high-pressure loads in use Andy, but I only know of one Kaboom job in F/TR from my 12 or so years in the discipline. That was Steve Donaldson's rifle in one of the very early European F-Class Championship meetings at Bisley, in pre small primer brass days. The NRA technical investigation gave the handloads a clean bill of health and attributed the failure to a material fault in the rifle receiver. I can't remember the make/model, but it was a relatively rare American design and has been banned at Bisley by the NRA ever since.
Norman Clark, gunsmith and member of the NRA's technical committee said to me once that disastrous failures of factory ammunition were more common than handloads. Bear in mind too that the NRA's OWN procured factory 308 for TARGET RIFLE had to have an entire annual shipment of several thousands of RWS rounds made by RUAG withdrawn and returned. (It was just within SAAMI max, but over-pressure in the slightly 'tight' barrels used in TR rifle builds as I'm sure you're acquainted with and produced an 'Imperial Meeting' now remembered for stuck bolts and blown primers rather than high scores.)
I do worry a lot about the increasingly widespread provision of large and small primer cases for a growing number of cartridges which allied to considerable case capacity variations can see a hot but safe load in one make of SP brass become way over pressure in a different make of LP cases. The really hot loads I see at Diggle these days are more likely to be Creedmoors of one persuasion or another, and the 6.5X47 Lapua must be the most serially over-loaded cartridge of recent history.
Talking case capacity and its pressure effects, I'm currently bringing my old long-range F/TR 223 rig back into service, but as the UK's only 223 F-Open rifle. (Don't ask!
) Having shot the cartridge in competition for many years, I have a lot of odd boxes of unused Lapua 'Match' brass still on hand procured over 12 or so years. I just happened to notice on restarting case prepping that early 'Match' Lapua brass lacking that word on the case headstamp and from cardboard 'gold box' days weighs 92-93gn, whilst another more recent 'Blue box' lot is around 98gn weight. The former holds 31.0gn water in a fireformed case; the latter 30.5gn. Whilst 0.5gn doesn't seem much, and wouldn't be in 300WSM, it has a considerable effect on the little 223's loads and pressures, especially when loading it 'warm' with 80-90gn bullets. A third lot, my most recent purchase, weighs 95gn, and I presume will have a capacity somewhere between the others, but I've yet to fire any to check. I batch all my brass new and keep it together throughout its life, but I now have three card box label colours in use and slightly different sets of loads.Cambridge Pimpernel
Active Member
Cambridge Pimpernel
Active Member
Yes it was. The teams shoot on Saturday was humbling even for the national long range wind coaches, who were just shaking their heads laughing. Wasn’t until 1200 on Sunday that i worked out why I was inexplicably shooting 2 min groups. New scope, and I hadn’t adjusted the cheekpiece, and so was straining through the scope, applying different cheek pressures and not consistently aligning optics each shot. Dropped the cheekpiece 5mm, comfortable position returned and groups back to 1min. Cheekpiece position makes a difference!
Those with long memories may remember back to 1993, when a batch of ammunition made by Lapua was used in the Easter meeting. The ammunition had been loaded to a little under the maximum CIP pressure to ensure it performed at long range, but the fact that target rifle barrel dimensions were (and still are) a few thou' tighter than the CIP pressure barrel in which the ammo was tested (and which was made to minimum CIP specs) meant the ammo was over-pressure in most target rifles in use on the day. There were dropped primers and stuck cases galore, but for one individual, Brian Lewis, the consequences were much more serious. The back end of the case let go, his modern target rifle of European origin was not designed to handle gas escapes safely and he ended up with a face full of brass particles.
He would have been much safer had he used a Mauser 98 action, designed over 120 years ago, but which is a tour-de-force in action design to safely handle catastrophic cartridge case failure. See Stuart Otteston's masterly two books on "The Bolt Action Rifle" for a forensic examination of gas handling safety in action design.
Be that as it may, this is an incident will happen again while the NRA persist in allowing target rifles with dimensions that are smaller than CIP, and the Proof Houses carry on condoning it.
As for small rifle primers, I see that the Target Shooter magazine features an article by David Tubb on his XC cartridges, which he says are designed for a working pressure of 80,000 psi. Running his quoted loads through P-Max, I can only say the cases better be able to handle working pressures of 80,000 psi...!
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welshwarrior
Well-Known Member
was this the case that lead to the introduction of rule 150 on chamber sizes?
Ronin
Distinguished Member
Thabks for the comprehensive post Laurie (as always)
Yes I’m familiar with the tighter bores used with TR and have built a few F class guns over the years (mainly open class guns )
It’s always a worry when one sees threads such as this where the op is chasing a velocity to achieve rather than using what they can safely attain
Many try to emulate internet proclamations of hyper VO with no substance (dangerously so)
The advent of small primer brass does not help the situation as the laws of physics can’t easily be changed
Without high pressure, one will not attain high velocity but the containers used (cartridges and chambers) will only stand so much beating before they bite back
Yes I’m familiar with the tighter bores used with TR and have built a few F class guns over the years (mainly open class guns )
It’s always a worry when one sees threads such as this where the op is chasing a velocity to achieve rather than using what they can safely attain
Many try to emulate internet proclamations of hyper VO with no substance (dangerously so)
The advent of small primer brass does not help the situation as the laws of physics can’t easily be changed
Without high pressure, one will not attain high velocity but the containers used (cartridges and chambers) will only stand so much beating before they bite back
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