I built a .22 br in an rpr. Everything seems fine, except magazine. The plastic sr 25s work best so far. I have only used them and mdts. The sr 25 occasionally hangs up on the shoulder of the next case when ejecting, and also occasionally drops the bullet nose into the barrel face. The mdts rarely feed well, mostly not bringing the rear of the case high enough to cycle. Im going to polish them and see if they dont run better. Anyone elses experience?