6.5 gap saum

[LRRPF52]

I've been following a thread on Sniper's Hide about the 6.5 RSAUM made by GA Precision.

Basically, what George wanted was a lightweight hunting rifle that could do everything with, using these guidelines:

24" barrel
9 pounds or under with scope and sling and mag
Short Action
Low recoil
Keep at 58,000 PSI or less
at or under 6 mils to 1000 yards
1000 ft lbs energy left at 1000 Yards

By using very slow-burning H-1000 powder, they achieved this goal. He's also getting insane barrel life with it, as in over 3000 rounds easy, up to 4400 in his personal rifle, which he won Sniper's Hide Cup with BTW.

Here's a group George shot at 1137yds.



Everyone is basically walking away from it saying it's their favorite rifle to shoot. There are a lot of good things happening for the 6.5mm world, which has really caught on late in the US, even though there are plenty of old timers who knew the beauty of 6.5mm ages ago with the 6.5 Swede and .264 Win Mag. What's cool about the 6.5 RSAUM in George's approach is that he doesn't rely on crazy pressures to achieve velocity, he uses capacity combined with slow-burning powder.

[bwaites]

I've been following a thread on Sniper's Hide about the 6.5 RSAUM made by GA Precision.

Basically, what George wanted was a lightweight hunting rifle that could do everything, with using these guidelines:

24" barrel
9 pounds or under with scope and sling and mag
Short Action
Low recoil
Keep at 58,000 PSI or less
at or under 6 mils to 1000 yards
1000 ft lbs energy left at 1000 Yards

By using very slow-burning H-1000 powder, they achieved this goal. He's also getting insane barrel life with it, as in over 3000 rounds easy, up to 4400 in his personal rifle, which he won Sniper's Hide Cup with BTW.

Here's a group George shot at 1137yds.



Everyone is basically walking away from it saying it's their favorite rifle to shoot. There are a lot of good things happening for the 6.5mm world, which has really caught on late in the US, even though there are plenty of old timers who knew the beauty of 6.5mm ages ago with the 6.5 Swede and .264 Win Mag. What's cool about the 6.5 RSAUM in George's approach is that he doesn't rely on crazy pressures to achieve velocity, he uses capacity combined with slow-burning powder.

Details on velocity and bullet?

[mongoosesnipe]

that barrel life is amazing considering what velocity he has to be shooting base on my calc with the berger vld hunting 140 he needs to be around 3250 which is lazzeroni and stw Territory and to be doing that out of a 24 inch barrel is a miracle...in it of it self, that said.... i want one....

[adamjp]

I'm halfway through building one. Action in, reamer in, barrel still on order (Lilja 26in Fluted Rem Sporter, 1:8, 3 groove). It will go into a Wildcat composites stock with a Zeiss 2-15x42 HD5 scope on top.

Since there is a 3100fps limit on the steel matches he built the rifles for, the 6.5 RASUM romps it in with a 140gn bullet at 3100fps. That 4400 rounds was achieved with a single setback of the barrel at 'about 1500 rounds'. I've been using AR2217 in my 6.5-06 and 7mm SAUM and it does appear to be somewhat cooler than the older powders, velocity is lineball with 2209 or 2213 (H4350 and H4831SC respectively).

I don't see the cartridge as a miracle, but it is a well executed idea and will make a great mountain rifle cartridge for my use.

Oh and George uses Pointed Bergers, the 130gn for hunting and the 140gn sometimes too. The 130gn bullets are doing 3250fps or thereabouts.

[waveslayer]

I love my Lazzeroni Warbird... it's just a barrel burner and expensive. ..I would love to see this new cartridge. How effective are those bullets at those velocities? If I shoot anything below 120 yards with the 150gr. Warbird it just punches a big hole, too fast.

[montana]

It looks like a great cartridge but an expensive option. My friend has been experimenting with a 6,5-06 Ackley improved. It seems to be running close to the 6.5 RSUM velocities but we will have to see if the barrel life is as good. I'm seeing more and more 6.5 calibers being used and for a good reason. Thanks for the info I enjoyed it very much.

http://www.coueswhitetail.com/forums/topic/41495-65-06-ackley-improved/

[bwaites]

The barrel life talked about makes no sense.

I shoot a 7mm WSM. I shoot essentially the same powder loads as the 6.5 RSAUM. I have a bigger bore, thus a bigger piston to act on. I do shoot bullets which are heavier, but with similar or better BC's.

I get 1000-1500 rounds from a barrel using reasonable loads in competition. Guys that push it may get as few as 600.

I have a longer barrel, so it may make sense to try the slower powders, (I'm using H1000 and 4831SC now) but the barrel life talked about is insane, and goes against what everyone has been talking about with the WSM's, RSAUM's, and RUM's.

LRRPF52, any thought on how they are doing that?

[mongoosesnipe]

the velocity from the 24" barrel seems high, based on my calculations he has to push a Berger 140 at 3250 to get to the 1000ft/lbs at 1000 yards moving up to 4000ft of altitude in the thin air it can be done at 3100fps, but 3100 is still well into barrel burning velocity and that is still a really high velocity for a 24 inch barrel with a slow powder, is it a nitro-carborizied polygonal rifled barrel or something because even with a barrel set back that barrel life is obscene

[calshipbuilder]

He is running pointed 130's with an estimated BC of .600

[LRRPF52]

He only did a tiny setback because he had the barrel off anyway for installing a break. The principle he's using for barrel life is keeping the pressure low.

To push a 180gr 7mm at good velocity, you need pressure and case capacity. To push a 130gr pointed VLD at 3250fps, you don't need as much pressure, but do need capacity and as slow-burning a powder as possible. If the pressure is 53ksi - 58ksi, it doesn't gas check the throat like magnums normally do = short throat life.

There's another guy on SH who was doing this years ago, and took his rifle into a smith for some work. He had been doing the same thing: H1000 in a cartridge where H4831 and H4350 were more common. I think it was a 6.5 RSAUM actually. He had over 3000 rounds on it, and his smith called BS. He showed him his track of the round count, and accuracy was still superb. A lot of the magnums run 65,000psi, which torches the throat horribly. That's why a .264 WM, .300 WM, Weatherby Magnums, WSM, etc. burn barrels like cheap fireworks, only nobody wants a barrel to burn under 3000 rounds.

This cartridge has the potential to displace most of the magnums for long-range hunting and competition, especially as people catch on to the mild recoil/magnum performance, long barrel life. I've had plans to build a .264 Win Mag, or 6.5-06 AI in a long action, but have been looking at wildcats off the WSSM's and RSAUM too. The RSAUM case capacity is just right compared to the WSM for some reason, and the neck length helps as well. The lower pressure is the main principle though.

Looks like all the work has been done, and I can go short action as well. George also had Bushnell build him a spec'd lightweight, all-round long-range scope for both hunting and competition, to keep the rifle lightweight.

He just shot a doe antelope at 1268yds with the 6.5 RSAUM/Bushnell with the first shot through that scope after zeroing.

[bwaites]

He only did a tiny setback because he had the barrel off anyway for installing a break. The principle he's using for barrel life is keeping the pressure low.

To push a 180gr 7mm at good velocity, you need pressure and case capacity. To push a 130gr pointed VLD at 3250fps, you don't need as much pressure, but do need capacity and as slow-burning a powder as possible. If the pressure is 53ksi - 58ksi, it doesn't gas check the throat like magnums normally do = short throat life.

There's another guy on SH who was doing this years ago, and took his rifle into a smith for some work. He had been doing the same thing: H1000 in a cartridge where H4831 and H4350 were more common. I think it was a 6.5 RSAUM actually. He had over 3000 rounds on it, and his smith called BS. He showed him his track of the round count, and accuracy was still superb. A lot of the magnums run 65,000psi, which torches the throat horribly. That's why a .264 WM, .300 WM, Weatherby Magnums, WSM, etc. burn barrels like cheap fireworks, only nobody wants a barrel to burn under 3000 rounds.

This cartridge has the potential to displace most of the magnums for long-range hunting and competition, especially as people catch on to the mild recoil/magnum performance, long barrel life. I've had plans to build a .264 Win Mag, or 6.5-06 AI in a long action, but have been looking at wildcats off the WSSM's and RSAUM too. The RSAUM case capacity is just right compared to the WSM for some reason, and the neck length helps as well. The lower pressure is the main principle though.

Looks like all the work has been done, and I can go short action as well. George also had Bushnell build him a spec'd lightweight, all-round long-range scope for both hunting and competition, to keep the rifle lightweight.

He just shot a doe antelope at 1268yds with the 6.5 RSAUM/Bushnell with the first shot through that scope after zeroing.

I get all that, but to get velocity, you have to have pressure, and I just have a hard time seeing the velocities he is getting without higher pressures than that 58,000 threshold, especially in that shorter barrel.

JA, we need you to game this in your software!

[LRRPF52]

Someone on the Hide ran it through QL, and it played out almost perfectly pressure-wise. You do need magnum pressure to push a 180 VLD. You don't need it to push a 130gr VLD, as long as you have enough capacity. 24" does seem to be the bottom for barrel length, since such a slow-burning powder is being used.

The proof in the pudding about pressure differences is what happens when you throttle the 6.5 RSAUM up to 65,000 psi.

You can see that more pressure is needed to push a 180gr to 3000fps than a 140gr at 3100. As such, you can add more gas to the 6.5 SAUM, and push 140's to 3300fps at 65,000 psi, but why do it if you can get 130's at or under 6 Mils at 1000yds, and get accuracy life that is biting the heels of the .260 Rem.

I've been telling .260 Rem/6.5x47/6.5 CM shooters for a while that the 130gr VLD is overlooked in favor of the 140 class bullets. It's BC is so high that combined with velocity and pointing, you can exceed the 140's. I already do that with my .260 Rem AR10 compared to what 140's limit me to velocity-wise, and I haven't the time to point. Without pointing, the 130gr VLD already beats the 140gr A-MAX, since their BC's are very close, but the 130 will go faster for the same pressure.

[bwaites]

Someone on the Hide ran it through QL, and it played out almost perfectly pressure-wise. You do need magnum pressure to push a 180 VLD. You don't need it to push a 130gr VLD, as long as you have enough capacity. 24" does seem to be the bottom for barrel length, since such a slow-burning powder is being used.

The proof in the pudding about pressure differences is what happens when you throttle the 6.5 RSAUM up to 65,000 psi.

You can see that more pressure is needed to push a 180gr to 3000fps than a 140gr at 3100. As such, you can add more gas to the 6.5 SAUM, and push 140's to 3300fps at 65,000 psi, but why do it if you can get 130's at or under 6 Mils at 1000yds, and get accuracy life that is biting the heels of the .260 Rem.

I've been telling .260 Rem/6.5x47/6.5 CM shooters for a while that the 130gr VLD is overlooked in favor of the 140 class bullets. It's BC is so high that combined with velocity and pointing, you can exceed the 140's. I already do that with my .260 Rem AR10 compared to what 140's limit me to velocity-wise, and I haven't the time to point. Without pointing, the 130gr VLD already beats the 140gr A-MAX, since their BC's are very close, but the 130 will go faster for the same pressure.

You realize I'm going to end up with either a 6.5 WSM or RSAUM, right? I already have the platform. Just would have to rebarrel. Since I have hundreds of WSM cases, I'll probably just neck them down. I don't think there is a whiskers difference in the two, and with all that brass it makes no sense to change otherwise.

[mongoosesnipe]

I under stand the concept of low pressure extending the barrel life and I don't doubt the figures I just tint think that is typical for such a cartridge sending that much powder into the barrel will wear on the throat regardless of pressure and he is getting greater barrel lif so far than many lower pressure cartridges that said I think his barrel must be an exceptional example of what ever style of riffling and steel it is

[LRRPF52]

For F-Class, you could be even more competitive, and get way more trigger time with the gun. Would make a most excellent boomer slayer too. I've had a bolt gun build in the back-burner, and don't know when I'll be able to get into one. I don't dare touch my Pre-64 .270 Winchester, even though I've been tempted to re-barrel in .264 Win Mag or 6.5-06 AI.

About brass: George is going to be pushing hard with the brass makers to get production 6.5 SAUM made, since it is taking off quickly.

I'm thinking about Proof Research for a 6.5 RSAUM. Another great thing about this system-based approach is that it gives us an excellent AR15 carbine/rifle optic for the Grendel with George's reticle design. It has the close-in doughnut for dangerous game and CQM, as well as provisions to hold or dial for distance, with low-profile knobs. He mentioned something about a military version in FDE too.

Funny thing is that the guy's he's been testing these 6.5 RSAUM's with are using really low-profile, lightweight scopes from S&B (10x42 PMII), NF (2.5-10x42), March, and now this Bushnell prototype. As people in the competition circuit are finding that lightweight, high-performance cartridge/ high-performance lo-profile optics combo's are the way to go over heavy target guns, we'll be seeing more and more products cater to the trend.

We already have seen that the Grendel gets superb barrel life compared to other 6.5's and even the .308 Win, even though 6.5's are known for being barrel eaters. How much of a factor is the Grendel's low MAOP in that equation? I think a lot. Drifter and Bwaites have shot Grendels enough to know what kind of accuracy life to expect, and it is very high for a high power rifle, especially one with significantly longer projectiles.