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20 Practical Brass Question

Mark M.

Silver $$ Contributor
Just finished a 20 practical build, what is the best bras to use for this in the AR platform, thanks
 
Expect about seven to ten (+/-) loadings if using moderate loads with good brass like LC or Lapua in an A/R so I would go for the Lake City at a fraction of the cost. Because of the bit of case stretch that is inevitable when firing in an A/R, the brass seems to have a limit on the number of firings no matter how good the brass is. I just paid about $280.00 for another 5,000 pieces of once-fired LC from armorally.com (Potomac Brass). That would buy you 500 pieces of Lapua. I turn the necks after sizing down the LC and anneal every three firings. I'm usually left with about 90%+ of my original lot when it is time to recycle it. The Lapua will go a few more firings before cracks in the necks but that is the only advantage for paying 10x more. I used a large batch of Remington brass in one of my barrels and I was constantly trimming for length as that brass was much softer than the Lapua or LC and flowed pretty bad. The other American military brass is also good. NOW - if I were using it in a bolt gun, I'd be much more favorable to spending the extra on the Lapua as you can get maybe 20-30+ firings on it, whereas the LC won't last that long. I had fair experience with Winchester commercial also.
 
When I first got my 20P I bought some Lapua brass for it. Before the rifle was finished I also bought about 3K LC cases. So, in order to not ruin any Lapua brass, I did all my initial workup using the LC brass. The rifle shoots great with the LC so, I never bothered to use the Lapua brass. I use the LC brass until the primer pocket goes south, (3-4 firings) and then chuck it.
 
When I first . . . I use the LC brass until the primer pocket goes south, (3-4 firings) and then chuck it.

Would you say you push your brass hard? Whose dies are you using?
My questions are in line w what seems to be shorter than normal brass life. Jes' curious.
 
Expect about seven to ten (+/-) loadings if using moderate loads with good brass like LC or Lapua in an A/R so I would go for the Lake City at a fraction of the cost. Because of the bit of case stretch that is inevitable when firing in an A/R, the brass seems to have a limit on the number of firings no matter how good the brass is.
I read similar recommendations (some even say to toss the brass after 4-5 firings). So I decided to run a case life test. I got up to 35 loadings and NONE failed due to case stretching. YMMV
 
OK, batting .500 on questions.....care to continue?

When I get the brass it has already been shot once. Right now I using H-335 at 26.0 grs. Don't remember offhand, (not going downstairs to check) but I believe that is 1 gr. over book max. As I'm repriming cases, I chuck them if I feel, even the slightest, that the primer went in to easily. Sorry for not answering you properly but, I've been working on a new 280AI, (first Ackley ever) and my thoughts have been elsewhere.
 
I'm loading 23.8 gr of VV-133 with 39gr Sierras and Lapua brass. I'm on my 6th loading and pockets are still great.(bolt gun)
 
I use LC brass on my Practicals. Have a small batch of Lapua brass but quit using it because the volume is somewhat less than LC, enough to have to adjust the load which was bothersome. Accuracy is just as good when I prep it and does last a long time.

John
 
The only reason a lot of us are able to get 30+ loadings out of our brass (and I do) in a bolt gun is because we don't have to size the brass down as much (if at all) and push the shoulder back as much as one does in an A/R in order to make the A/R ammo function properly and safely. In the A/R, that entails sizing the case down - even if just a bit - and pushing the shoulder back at least .002". Granted- if one fails to push the shoulder back - most often, it will get pushed back when the bolt slams home. It takes very little pressure to push the shoulder back a few thousandths. Even with zero shoulder clearance - most all AR-15's are going to require some sizing to properly load. All said - if one loads a .20 Practical with minimal body sizing and shoulder setback - there IS going to be a bit of case stretch and brass flowing forward which gets trimmed periodically IF the shooter is loading a load that would produce the velocities that 99% of us would likely use. To imply that guys could normally (and safely) get 30 loadings on brass out of a normal-powered .20 Practical load fired in an AR-15 is, in itself, a bit of a stretch. And for those using short-base dies - I think it is an impossibility. To those who do (?) - I salute you!
 

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