Will 77gr work in 12 in barrel?

[1st MAW]

Gentlemen,

I just purchased two 12in bbl ar uppers. Would someone please tell me if 77gr will be viable in these barrels or will the velocity be too low for 77gr to break up?

[docsherm]

It will work just fine. The 12.5" barrel is the shortest that you can use to get the maximum effect with .77 gr ammo.

That combo is what I use. It works great.

[Onyx Z]

Need more details. What manufacturer? Barrel twist? etc There's more to it than length (that's what she said).

[1st MAW]

I purchased the uppers from Palmetto State Armory, 1 in 7 twist barrels....What would be the maximum effective range, 150 yds for the bullet to work? I am curious as to what muzzel velocity i can expect as well.

[1st MAW]

Jackmobes,

I was told that 1/9 twist barrels would give you keyholes with heavy bullets.....

[Onyx Z]

Jackmobes,

I was told that 1/9 twist barrels would give you keyholes with heavy bullets.....

This is a common misconception. Velocity and twist rate are generally interchangeable. Naturally, YMMV.

I have a 1/9 CL barrel that puts my 77gr handloads in 3/4moa @ 100yds with a clean-copperfree barrel. Any further out or dirty, I have no clue. I haven't tested that.

[1st MAW]

Onyx,

What velocity are you getting at 100 yds?

[Onyx Z]

Onyx,

What velocity are you getting at 100 yds?

No idea. This same load runs 2,700fps from my 18" at the muzzle and just over 2,650fps from my 16" barrel.

[docsherm]

I have a 12.5 Noveske and I shoot MK 262 with a Can all the time. I have only had it out to 300 meters so far. I am sure I can get a lot more out of it. When John Noveske first started messing with the 12.5" it was to get the shortest barrel to stabilize the the Mk 262 round. He cracked the code. It works very well.

[markm]

I've fired 77s from an 11.5 at contact distance, and they fragment brilliantly. Not sure how far out this works.