220 Russian brass to 6.5 Grendel?

[Constitutionalist]

I've converted a bunch of 7.62x39mm but stumbled across a bunch of cheap 220 Russian. Has anyone tried converting this brass to 6.5 Grendel? If it's doable I may pick it up and give it a shot. Something to do to keep me out of the bars. Oh wait- they're closed.

Thanks in advance!

John

[Lemonaid]

No actual experience with 220 Russian but the theory looks sound to me as 6PPC brass is often converted from 220 Russian. To me it would look to be even easier to covert to 6.5 Grendel. If you have a source of cheap 220 Russian brass I don't think you will be sorry getting some.

[lazyengineer]

Hmm. INteresting. Idon't know the relative headspace, but so long as the headspace isn't shorter than Grendel, that part should be OK.

But 5.56 stretched to 6.5 mm seems like a pretty long stretch. Assuming same brass thickness, and using 2 pi r = circumf.
6.5 mm @ 2*3.14*6.5/2 = 20.4 mm of circumference around the neck

So stretching up 6 mm is an 8% stretch. And with neck walls now 8% thinner (ish)

Stretching up 5.56 is a 14%stretch. with neck walls now 14% thinner (ish).

I don't know where the threashold is on such things that this actually matters. I've gone from 6mm to 6.5mm all day, no problems. And I've gone from .270 to .308, which is a 12% stretch, and seemed to work fine. So my guess is you should be OK there. Though if you do have abilit to anneal, maybe not a bad idea.

[Laman]

Lapua 220 Russian brass to 6ppc is probably the most used process among competitive benchrest shooters. I have taken some of my 6ppc, expanded to 6.5 and attempted to fireform them to up to 6.5 Grendel. Even using the false shoulder method I couldn't get a well formed shoulder and the headspace was still a little short. My ppc brass was with turned necks for a .269 throat but there were no trouble expanding to 6.5, no splitting or collapsing. Just my experience,

[Constitutionalist]

Well, I found a piece of 220 Russian I'd picked up at a range years ago. I lubed it up well and ran it through my Grendel sizer die. I got it up to 6.5mm pretty easily but there's a slight ring at the base of the neck and the shoulder is still so sloped I'm not sure the headspace will be maintained. The extractor might hold the case during fireforming (but maybe not) and the shoulder is going to have to move a lot to fill the Grendel chamber. I'm probably not going to mess with doing them in quantity. Not sure, with the cost of the brass combined with a cast bullet and fireforming load, if it would end up being cost-effective.

Besides, I need to use my primers wisely. They may have cost 3 cents when I bought them but in the current market they are darn near priceless!

Thanks for the input, Gents!

John

[Happy2Shoot]

Post a side by side picture sometime if you can.

[Constitutionalist]

I have the picture but no way to post it. If you want to p.m. me your email address I will shoot it over to you.

[kmon]

You might try something I have done but has been a long time, seat the bullet to the lands to hold it against the bolt face for headspacing the cartridge for fireforming. I did that in bolt action not an AR.

Most I have necked brass up is .05 from .308 to .358 you would be a bit less than that.

[Constitutionalist]

Here's a picture of the resized 220 Russian case next to a Hornady Grendel case.

https://hosting.photobucket.com/images/v134/Beaverhunter2/220_Russian_resized_in_Grendel_die.jpg?width=450&height=278&fit=bounds&crop=fill