I recently bought a used CMMG M4 style 22lr upper for a build I was doing for my daughter. She has been coming to the range lately with me and I wanted to get her introduced to the AR15 platform. She is not quite ready for a .223 but really enjoys shooting 22lr. I built a lower and outfitted the lower and upper with pink Magpul MOE furniture like she wanted. The CMMG upper came with a stainless bolt carrier but the forward assist was fake. I had bought a 22lr upper direct from CMMG about 2 years ago and that one came with a stainless bolt carrier, forward assist adapter, and a working forward assist. I figured that I would order the forward assist kit and forward assist adapter and I would have it working like my first one. I was wrong. The forward assist kit went together real easy and then I installed the forward assist adapter. I noticed that when pulling the charging handle, the bolt carrier did not go all the way to the rear. I saw that there is a tab on the rear of the FA adapter on both this and my other upper but on the other upper there is a notch in the rear of the carrier for that tab. I contacted CMMG customer service and asked for possible solutions. I was contacted by Justin H who explained that I had an older version of the bolt carrier. He told me that he was going to send out a new frame to me, no charge. I received the new frame and installed it right away. I now have a properly working 22lr bolt carrier for my daughter's rifle. A big thank you to Justin H and to CMMG!!!