ADCOM 99 Lot Ammo Popped Primers?

[Low Drag]

I know there's been lots of posts on ADCOM ammo, specifically 99 lot ammo and popped primers. The jury has said "over pressure". I had a thought.... What about the primer pocket in the brass?

I used my calipers and found:
1999 lot ADCOM: .177
Any other brass I had: .174
Primer outside diameter: .175

I have a buddy that has some and was discouraged with his carbine, he couldn't get this stuff to group. So I gave him some other ADCOM, 98 lot and it did much better, along with some Serb M195 stuff.

I used some of the 99 lot for CQB blasting and got a couple of popped primers.

Anyway, has anyone else had the 99 lot ADCOM and if you have had it and got some popped primers could you measure the size of the primer pocket?

[fourrobert13]

Just this past Thursday me and my brother were shooting our AR's. I was using Adcom 98 and he was using 99. I had no problems and he had 2 popped primers. The second popped primer gummed up the works on his rifle. We had to wait until the rifle cooled off before we were able to clear the problem.

[UVvis]

LowDrag,

I've considered the primer pocket to primer size difference and think that is the culprit. I don't know the exact numbers, but my fried and I chrono'd a few of the primer popping '99 rounds and the velocities seemed reasonable. I actually think they were less than the mil issued m855 he had. We couldn't rule out pressure for sure because we don't know how the powder they are using performs.

[Low Drag]

On the Adcom 98 lot stuff, it shoots pretty well as does 2000, at least that's what I heard about 2000 lots.

I was able to get good hits out to 600 yards with the Adcom 98 so something must be right with it.