i trying to make my glock 20 mags work in my oly 10mm upper.  i got the mags to fit in the lower but i'm getting feeding problems.  when i load rounds in the mags and manually work the bolt, the rounds feed perfect.  it's when i go to the range and fire rounds off i get the feeding problems.  the rounds are get  jammed in the upper.  the bullet tip is facing upwards where the gas tube would be.  got any ideas why?

its not lining up with the chamber obviously



open the dust cover and see if they actually line up

they do line up.  if i lower the mag the bolt doesn't feed a round.  the bolt goes right over the rounds.  if i make the mag higher, the bolt hit the mag