Since I started shooting prs I have used MDT aics mags. My 12rd and 10rd with extension both feed the first round like butter but the std 10rd seems to have so much spring tension it's a little still for the first few rounds. I run the 10rd with extension most of the time but when. I get to a stage it might fit I run the std 10rd. It always feeds, just takes more pressure on the first couple rounds. I have all my feed lips tuned the same, polished and de burred the follower. Just wondering if anyone has a fix.