Causes of Doubling (other than disconnector)

August · #1 02-04-10, 16:14

I have a varmint gun that started doubling yesterday. It has run fine on previous trips to the range, but on the third shot yesterday it went full on me. Shot a couple of more magazines and the problem reappeared with each of them.

Today, I cleaned the gun and function checked it thoroughly. The disconnector caught the hammer every time -- so, it function checked as gtg.

This gun has a Geissele trigger. I'm wondering what other issue might be causing the doubling. Is it possible the carrier is not fully cocking the hammer during cycling??? Is it possible something is "bouncing" during cycling which is causing this issue???

Is it safe to assume that cleaning the gun might have eliminated some piece of crud from the FCG and the problem is gone???

Thanks for any pointers you might have.

bkb0000 · #2 02-04-10, 16:28

by "double," do you mean a consistent 2 round burst? or does it sometimes fire 3+? if it's 100% limited to 2 rounds, are you sure the second shot isn't happening at reset? have the trig/hammer sears been polished since leaving the factory? how many rounds on the FCG?

TY44934 · #3 02-04-10, 16:45

I've seen it caused by 2 things:

1) At a match, a shooter's hammer pin "walked" and was sticking partly out of one side of the receiver. Gun doubled. Easily fixed.

2) I installed JP trigger and hammer springs on regular AR15 hammer & trigger. Got light strikes so I switched to Federal brand primers.

Gun worked great off hand, but when shooting off the bench & really concentrating on squeeze & follow-through, the gun sometimes doubled - I think it was more of a "bump-fire" effect, really. Anyway - I didn't tolerate that. I immediatly bobbed the hammer & went back to a full power hammer spring - which slightly increased the trigger weight but curred the doubling-type phenomenon.

Eric · #4 02-04-10, 17:48

Go to the source.

www.geissele.com
Geissele Automatics
Mailing Address
603 Caroline Drive
Norristown, PA 19401

Shop
1920 W. Marshall St.
Norristown, PA 19403

Call Direct: 610-272-2060
All customer services inquires should be directed to Amy@Geissele.com*

August · #5 02-04-10, 18:57

Eric:

Thanks! Geissele's web site has been completely dismantled with no links functioning. So, I was glad to have Amy's address. Thanks again.

Artos · #6 02-04-10, 19:12

August,

the only double i ever dealt with had to be a bump fire. I had turned down a 2 stage jewell and was free recoiling for groups. I certainly was not paying any attention to correct ar trigger work.

Was w/ an leo buddy and neither of us could duplicate. I was shooting a heavy 24" no taper and the shots were amazingly close on the paper.