High Powered Rifle casters....speed?

[Steel185]

I cast for several calibers, all of which are larger and slower than the 6.8mm SPC I'm getting into soon. I'm building an AR in this size. For those of you casters that use high powered rifles, what speed can you get out of using a 270 boolit? I've always been told if you cast usually you have to use a heavier boolit and slow it down. I'm sure you guys figured out how to meet the speeds of the factory ammo. Can I get it to 2500FPS?

[Dan Cash]

In a .30-30, I get 2200 with a grease groove bullet cast wood pecker lips hard and the same with a dead soft paper patched bullet. My other success is a .30-40 1895 Winchester; 2200 for a 215 gr paper patched and 2400 for a 175-180 paper patched. Both are dead soft.

[Larry Gibson]

Yes you can get 2500 fps with a 120 or less gr cast bullet out of a 6.8 SPC depending on barrel length. However most have 10" barrel twists and that will make it difficult to achieve accuracy at that velocity. The twist rate is simply based on what barrel twists is readily available and not what is needed. If the barrel twist was 14, or better yet, 16" then you could probably get top end velocity and accuracy with cast bullets and jacketed bullets would do just as well. As you barrel will probably have a 10" twist the 122 gr Lyman 280468 would be my 1st choice and the 280412 at 136 gr would be my second. With either of those I would expect you could push 2000 to perhaps 2200 fps depending on barrel length and maintain useable accuracy.

Larry Gibson

[dverna]

If you doing a build, and shooting cast is important to you, heed Larry's advice. Try to find a barrel with a slower twist. It may be worth the effort and expense.

Don Verna

[7br]

I shoot an AR15 with a DPMS 6.8 upper and RockRiver lower. I am using a 115gr mould from Mountain Molds and am having decent luck with it as far as accuracy. I did put an adjustable gas block on it. I get good function with H322 and H4895 somewheres north of 20grains of powder. One of the issues you will have with heavier bullets is magazine length. A couple of factors to think about is that you will not have the camming action of a bolt gun to engrave the rifling, so your fit will need to be pretty close to dead on. The mould I am casting is actually my second design iteration as I miscalculated how fast the ogive would fall away from the rifling and it was giving me fits feeding. I also have issues with the flat nose hanging up on the feed ramps on the first round out of the magazine. Subsequent rounds feed fine as long as the rifle is clean. Good luck and keep us posted.

[Blammer]

I cast for several calibers, all of which are larger and slower than the 6.8mm SPC I'm getting into soon. I'm building an AR in this size. For those of you casters that use high powered rifles, what speed can you get out of using a 270 boolit? I've always been told if you cast usually you have to use a heavier boolit and slow it down. I'm sure you guys figured out how to meet the speeds of the factory ammo. Can I get it to 2500FPS?

yes you should be able to get close to 2500fps, it may take some technique for sure but it's doable.
personally, I'd settle for predictable accuracy at a bit slower.