gun is jamming HELP!

[Blitz43]

I have a automag classic w/ very little modifications, i am running N2 and when i start to fire after about 5-20 shots randomly it will jam, to fix i have to hit the back of the gun with enough force to re arm it. Has any 1 hurd of this problem before? can any 1 help?
-thank you for ur time

[shades]

It is called bolt stick. If you degas the marker it resets the bolt.
You might want to Put 3 drops of Three in One oil in your ASA and decrease your input pressure if you can. Then shoot it with the barrel off about 100 times.
NEVER put oil into your tank fill nipple EVER!!!! Or BOOM!!!

[Blitz43]

hmmm well i am kinda new at the mags could it be any other problems? i thought it might be bcause of my trigger frame, the hole for the screw going into the bolt part seems to be a lil big. i thought it might be letting it slip back thus be hitting it back into place caused it to fix but u are sure its a stick?

[Tunaman]

Is the rail bushing in there?