I have a Ruger 10/22 (22lr) that I have been using for the last 10 years with 50 round Ram Line plastic magazines. I have recently been experiencing failure to feed, where the round hits the ramp and sticks. A push on the bolt normally closes the bolt but at that point the round will not fire. I clear the round and it fires fine from there. Typically I get 10 jams per magazine after about 50 rounds and 1 or 2 per magazine when the rifle is clean. I am using three of the 50 rounders and they all malfunction (after all three worked fine up this problem). What is interesting is that I get no jams with the Ruger 10 round factory rotary magazine. The next step is to try the 50 rounders in my buddies 10/22. I have also tried replacing the recoil spring without it helping. What do you guys think?..Bogger