I have a 502, i'll tell a story about FN customer service. I locked the first one up tighter than a drum shooting it suppressed. don't know what happened but it was gone. took it to a gunsmith and he said it was toast so he sent it back to FN for me and they sent me a brand new pistol. Guess it wasn't worth fixing. could really tell what happened to it but the whole lower grip assembly was locked up. the backpressure from the suppressor got it i guess. i have shot the new one suppressed some, maybe 100 rounds so far.