View Full Version : geissele 3 gun

17 October 2014, 18:37
I put a geissele 3 gun trigger in my San tan lower not realizing how quickly you can spout off rounds with it. I had a theory that the gun could shoot faster if I could get it to cycle quicker. Starting with a standard buffer assembly and bolt, I did the following...installed a vdi low mass bolt, tuned my gas block to toss the bolt just far enough back to catch and lock the next round and then tested. It seems to have worked and with a Rainer arms comp the rifle barely moves. The biggest speed difference was realized when bump firing the trigger, which you can do with just a little practice. It's a great trigger. You won't be disappointed.

17 October 2014, 19:04


Bump-fire isn't a 3-gun technique and you've likely successfully tuned the gas block to that ammo. Anything that shoots softer won't cycle. You can also have problems with hotter ammo, too.

You will probably experience some extraction issues as well as feeding issues from the magazine. At half compression the spring doesn't offer much forward force to peel a round out of the magazine. Your mileage may vary.

18 October 2014, 06:28
The looming question with all the low mass equipment floating around is why? Less felt recoil? Faster cycle? If you've looked into any of it you've noticed that everyone has a question but no one has an answer. This thread is the answer to many of those questions. I didn't get the trigger to compete, I got the trigger because it shoots faster than any leading competitor. The shot splits on a full auto are .1, this trigger they're .12. From that point it was just curiosity to see how quickly the rifle could fire.

18 October 2014, 13:20
I get why you did it. I'm not making an opinion on that fact. Shooting fast is fun, to a point (usually about $40 in ammo). If that Geissele trigger gets you to your desired cyclic rate, cool.

And using a carbine length M4 cycling rate, you are looking at .07 sec/round (about an 850 rpm average). I'm very impressed if you can achieve a rate of fire only .02 sec slower. Generally, even with short reset trigger and a good bump fire technique is still a clean 1/3 or more slower than full-auto fire.

Get a shot timer and record your true fire rate.

18 October 2014, 14:28
I'll look and see if there is one kicking around. Otherwise I'll run a slow motion camera on it and time it. I'll post the results. Good idea