I have a strange issue going on that has a solution I can't quite put my finger on. TL:DR at bottom.
I've had a DSA SA58 11" for about 2 years now. For the first 1.5 years it shot alright with no weirdness, other than it being so overgassed that DSA wanted to take a look.
I send it in, and they end up replacing a number of parts, including the barrel.
Since that time, it's appropriately gassed, but now I'm seeing wobbling bullet strikes on paper at 25 yards. Not keyholes, but definitely stability issues and slight oval holes.
So I think, ok...maybe it's a 1-12 barrel or maybe there's a crown issue. Sure enough, there's only a crown on about half the circumference of the muzzle. I don't think I'd have problems at 1-12 for full power 147gr, and the crown thing has been somewhat debunked for causing MAJOR issues, but I got to experimenting to try and prove it to myself.
I take it to the range today, and shoot two factory 147gr M80 ball ammos - Magtech and LC. I put up 4 targets and shoot 3 rounds of each ammo into each target with different muzzle conditions: a bare muzzle, one with DSAs flash hider, one with my YHM QD brake, and one with the silencer on the QD brake.
The bare muzzle and DSA devices look fine (normal round holes). The YHM brake is bad and the brake + can is worse. It's bad enough that if I hadn't shot them myself I would have expected baffle strikes.
There are no baffle strikes in the can and no evidence of rounds contacting the inside of the brake. This is also the same exact brake and silencer combo that I used before on the previous barrel that produced no oval holes.
I'm at a bit of a loss at this point. I really wanted to shoot this suppressed. I have one additional brake (new, and slightly different config) I can install and try, but after that I'm a bit light on ideas.
Any other things I should be looking at?
TL;DR - old barrel shot fine, new barrel shoots questionably from a stability perspective, but only on muzzle devices that were fine on the old barrel and show no signs of contact with bullets.