Sent my CRM to Kel-tec do to Bolt catch breaking and not being able to lock bolt open. This was after couple mags being fired. After 5 weeks received back with repairs and new S/N. Went to range to have some fun with my repaired CMR and after 5 mags of 40gr called it a day. As I was cleaning my CMR I noticed that I couldn't lock my bolt back. Removed the disassemble pin and the tip of bolt lock was broken off. Same as previous failure. Firearm will operate except it will not lock back after last round and you can not lock back manually. I would advise that all CMR owners to check and see if you can lock your bolt back. I like to run a bore snake after each range visit. Hard to do if you can't lock the bolt back. I don't see any point in spending money to send CMR to Kel-tec until they have a fix for this problem. I'll use it the way it is for now.