These are both AAC M4-2000mod08 silencers. According to the posters neither have had a lot of rounds through them.
Blast baffle on short gun with a brake:
Blast baffle on short gun without a flash hider:
Erosion on muzzle brake from first can:
Thanks for posting those pics. That is exactly what I was talking about. Far better to let the easily replaceable mount take the beating instead of the expensive to repair suppressor.