There are lots of worrisome comments about peening in M1A and M1 rifles when loading 2520.
Peening was a curious phenomena that the military had in M1's and ball powder. I forget the causes or the cures, but I think peening is a mute subject today.
Back in the 80's AA2520 was the hot new M1a powder. Jugs and kegs and tons of it were shot through M1a's without any problems.
Not only did it shoot well, but it meters fantastically. Not that it makes any difference on paper.
Yesterday I shot a HM score with 69's in the .223.
I bought a lot of the stuff when it was $64.00 a keg. But all things being equal, I prefer IMR 4895. Some lots of AA2520 were real dirty stuff, almost like charcoal dust, and I hate having to use a copper bristle brush cleaning deposits off my AR bolt. Which is what I did yesterday.
I have shot AA2520 in the M1, shoots very well.
I shot this prone rapid fire group with AA2520 and a M1a at our Club's 100 yard reduced Highpower match.
Stuff shoots well.
Any caliber combination that shoots well with IMR 4895 will also shoot well with AA2520.