Re: AR-15 burst firing? Need Advice!
I've been told that swapping the bolt hold open spring with the disconnector spring can cause this.
The two springs appear very similar, and the conical spring CAN be forced into the spring pocket for the bolt hold open.
The instance of this I was told about acted this way:
Pulling the trigger would properly release the hammer. Keeping the trigger held back while recocking the hammer showed the disconnector working properly. If the trigger was released quickly, the disconnector would properly make the hammer "handoff" to the sear. However, if you tried to "reset" the trigger very, very gently, rather than the disconnector handing the hammer off to the sear, the hammer would simply drop.
I was told that while actually firing the rifle, it was impossible to NOT let the rifle run full auto.
As already mentioned, besides the felony you have currently avoided being charged with, you've got an out of battery discharge accident waiting/trying to happen. M16s and M4s have a mechanical "timing" system that assures the bolt is in battery before releasing the hammer. Your felony rifle does not have this.
I'm don't want you to feel like we're being hard on you - its just that we don't want to see a fellow enthusiast find themselves in trouble.