I purchased a full auto cobray Mac 11 last year (new). And I load up a 32 rounder and it shoots in semi. Once in a while it will it will cycle a few rounds at a time. I know the mags suck (zytel plastic mags) I have about 10 mags some brand new they all do the same. I noticed that if you load only about 5 rounds the spring seems to have enough force that it should work. If you load anymore than that the spring dosen't have enough force to snap the rounds up like they should. Also when firing alot of rounds end up on the ground like they are poping out of the mag and out of the gun and onto the ground. The only thing I can think is maybe the mag well (grip) is to tight and is compressing the mags or some thing is wrong with gun. Please let me know if any of you has had this problem thanks: