"parts came in today and I immediatly got on the task of installing everything. The pro-mag magazine adapter require the removal of the bolt catch so that the adapter can slip in to the magazine well. That is what I first did, tried a few mags, have 2 makers, 2 styles. C-products steel 32rnd mag, pro-mag poly 32rnd mag and a pro-mag 32rnd parkarized steel mag. none of the magazines tripped the mag catch and held in. I filed some of the adapters opening for the mag catch and it showed improvement for the promags. and slight improvement for the c-products mag. but still would come out with enough wiggling. I put 20rnds into each mag assembled the rest of the AR and went to my range (my farm) I started with the parkarized promag, still had issues holding it in at start, though after a few rounds (yes did feed will, no jams) the mag locked in. before I spent all 20rnds I put in the poly promag magazine, locked in better and a after a few rounds it was sturdy holding in the adapter as the other had been, again no jams. Finally I put the C-products magazine in, jammed on the first round. pulled in out and put another mag in, no problems. wend back to C-product mag, same problem... the bolt is getting caught half way closed, I am assuming the mag rides a bit high, or flares a bit wide and catches the YHM bolt in the upper causing it to fail to close the bolt. The promag adapter also has a bolt hold open piece, I had not found that to function as of yet, possible the ammo is too weak, but will continue to play with it this weekend.
ammo used is mixed casing reloaded with round nose 115grn lead target ammo."