https://imgur.com/a/QeVBkoS

Sorry RC2 bros, but took out the PS90 SBR out for the first time and ended up getting a small booboo. After zeroing, did a mag and a half mag dump, with about a bit less than half a mag with the RC2. I distinctly heard a ting sound that I thought was weird and thought maybe it was a baffle strike, but a quick look down the can at the range I saw nothing and thought nothing more.

After getting home, taking a closer look at the can, the inner edge of the endcap is a bit pushed in, and you can barely see it in the pic. The white line above the bottom rim of the endcap is a bit of pushed in metal. It looks like it hit the inner edge of the rim and bounced downwards. Checked with a 5.56 alignment rod and it seems to be perfectly concentric. Not really sure if its the PS90 and its moving barrel that causes issues with cans, or I didn't tighten the collar down enough, or what.

Took a vid of my shooting, and on the third shot, you see a spark (or round??) bounce downwards, which kinda makes sense as the endcap strike was at the top side of the can.

I don't plan to shoot this with a can often due to stories of stocks cracking, but it is kinda bugging me that something maybe a bit off with my setup. I've read stories of people having bad barrel chops, or bad adapters for the barrel, but with the rod looking straight not sure whats up.

Was shooting SS197SR. RC2 has been through 1K ish rounds so far with my 5.56 guns no problem at all, and has not been cleaned at all yet.

At least it looks like very minimal damage was done. My 1st uneducated guess would be the can had the slightest wobble when you were firing. My 2nd uneducated guess is that between stacking tolerances of the mounting system and/or the nature of the PS90 barrel movement, in addition to normal recoil, is what induced enough wobble for the projectile to kiss the endcap.

 I'm a firm believer in using larger diameter than 5.56/.22 bore cans with the PS90. You'll always have the supersonic crack of the projectile unless you are shooting subs so it's best to just focus on mitigating increasing backpressure and the cutting down on the bang at the muzzle with the can. I know there are aftermarket solutions in regard to keeping the gun from beating itself apart (which might be the ticket if you only own small bore suppressers) but that's just money spent treating the symptoms instead of the cause. And you'll never have to worry about shooting your suppressor off unless something went terribly tits up.

Guess I'll give my 762-RC2 a try.  Bigger bore and less backpressure.  I definitely felt the bolt slamming back with noticeably more force when shooting with the can vs no can.

https://imgur.com/a/QeVBkoS

Been using a SOCOM mini for nearly a decade with thousands of rounds and zero issues. Before this I was using a 556-212. The thread adapter can work loose on the barrel because the tensioning can be kind of tricky. Maybe the thread adapter got loose enough to allow a little wobble and cause this. I actually still have a Surefire P90 specific mount for my legacy 556-212 cans I opted not to use because it wasn’t really solid unless I cranked it down tighter than I felt it should be.