View Full Version : Going burst mode...on accident
Gentlemen, my "friend" has an AR that has shot a three and four round burst the last two shooting trips. It only happened on the first pull of the trigger. After that, each shot was a single round through three or four magazines.
The rifle is built on a spikes lower, geissele 3gun trigger, and H2 buffer. The upper is a standard BCM 14.5 BFH middie with a DD BCG. The magazines used were a brand new and fairly new Magpuls.
This is a new build so it has an extremely low round count, estimated at less than 400rds. No out of the ordinary wear marks, only the sligt cosmetic expected with the low rd count.
The first round was fired suppressed with an M4-2000 yesterday, but I cannot recall if the rifle was suppressed last time this problem occurred.
The rifle is dearly loved, and the lower has been SBR'd so my "friend" would like to be able to fix it. He also realizes the consequences of having a rifle that behaves this way, even if it is unintended. Can anyone diagnose the problem and detail a fix?
Nytcrawler93
09-15-12, 14:02
Disassemble the fire control group and replace it. I would also test fire it WAY away from anyone that is going to get you 15 yrs in a club fed.
GeorgiaBoy
09-15-12, 14:44
I remember reading quite a bit on this forum and others that just because a semi-auto somehow bursts a few times you aren't automatically convicted and thrown into prison. Usually whenever the ATF does convict someone theres more behind the story than a complete "accidental" full-auto burst.
It's the S3G trigger....I'm very confident about that.
It's not the trigger's fault per say, but rather the end user's lack of full control over the rifle that leads to "bump" firing it. That trigger is so light, smooth, and ultimately lightning fast that it's quite radical for most new users of it.
Seems to me your friend isn't paying as much attention to shouldering the rifle really soundly until he experiences a bump fire sequence.
The easiest remedy for this is to replace your current 3.5lb trigger spring with a gold colored one that is 5.5lb. It might have come with your friend's trigger, if not he needs to call GA and request one.
Nytcrawler93
09-15-12, 15:01
Like I said, replace the trigger. It is not worth screwing with the ATF, regardless of conviction rate, process, etc. This is a pretty straightforward situation.
Nytcrawler93
09-15-12, 15:02
I remember reading quite a bit on this forum and others that just because a semi-auto somehow bursts a few times you aren't automatically convicted and thrown into prison. Usually whenever the ATF does convict someone theres more behind the story than a complete "accidental" full-auto burst.
I agree that this is probably not enough to go to jail but why even risk it? Why have to screw with paying a retainer? It is a relatively cheap fix.
The trigger is a Geisselle. It's very unlikely that it's the problem
Nytcrawler93
09-15-12, 15:10
Could be the install.
Quote from Mr. Geissele....
" We ship both springs now in case a shooter has trouble with bump firing. With the lighter trigger pull that the black spring provides the shooter cannot hold the rifle loosely or feather the trigger or the chances of bump firing increase. Using the heavier gold spring will reduce chances of bump firing. The gold spring also helps like the one poster said where there may be a 4lb minimum weight requirement in some 3 Gun matches "
Quote from Mr. Geissele....
" We ship both springs now in case a shooter has trouble with bump firing. With the lighter trigger pull that the black spring provides the shooter cannot hold the rifle loosely or feather the trigger or the chances of bump firing increase. Using the heavier gold spring will reduce chances of bump firing. The gold spring also helps like the one poster said where there may be a 4lb minimum weight requirement in some 3 Gun matches "
Simply put it is the user not the device! It has taken me about 7 trips to the rnage to relearn follow through on the AR trigger in my SBR. I am so use to the extremely light pulls on my bolt rifles that I had been bumping the SBR unintentionally of course... The problem stopped when I do my part.
mvasilakis
09-15-12, 17:06
I had a similar issue recently. I took my wife's uncle shooting and my .45 went full auto on him... 3 times. Each time I took the gun from him and ran an entire mag through myself without issue. At first I thought the sear was done but when I could not replicate it I took a closer look at his shooting.
His follow through was poor. He was pulling the trigger and then releasing. Well the recoil pushed the trigger up against his finger and the light trigger dropped again. Also it didn't help that the bevertail safety was fit so it doesn't engage. (IPSC gun)
I'd assume the same is happening here.
I had this happen with a stock CMMG trigger. Except mine fired off a few rounds after my follow through was complete and i was releasing the trigger to reset it.
Seems the sear didn't catch properly and allowed it to fire off another round that caught me off guard and caused me to bump fire another couple rounds.
I should have sent the lower back to cmmg, but i was buying a CMC trigger anyways so i just junked that trigger. No troubles since installing the CMC trigger.
Thank you all for the reply! Number one, I love the trigger. Number two, because I consider myself a very experienced shooter with the platform, I'm very embarrassed the trouble is with the end user! At least its a cheap fix. I knew it wouldn't take any time before I found the answer here. Again, thank you.
Crap! I meant my friend was embarrassed!:)
This is not AR related but it is burst related. I have a Norinco 320 Model B. The first time I took it out using regular over the counter 9mm, it fired a burst of three and then stove piped. I cleared it and it shot fine the rest of the mag. The next mag it emptied and then stove piped the last round.Then I tried range reloads,and that caused it to stove pipe on every round. I bought a box of IMI UZI Sub Gun and the thing ran fine like it was supposed to. I just wondered if anyone had an idea?
I just wondered if anyone had an idea?
My guess: free floating firing pin was hitting the primer hard enough to set off the round (commercial ammunition generally uses softer primers), when you switched to the Uzi ammo the harder mil primers prevented this.
Bump fire for sure. Easy to do with those light triggers.
BufordTJustice
09-16-12, 03:01
It's the S3G trigger....I'm very confident about that.
It's not the trigger's fault per say, but rather the end user's lack of full control over the rifle that leads to "bump" firing it. That trigger is so light, smooth, and ultimately lightning fast that it's quite radical for most new users of it.
Seems to me your friend isn't paying as much attention to shouldering the rifle really soundly until he experiences a bump fire sequence.
The easiest remedy for this is to replace your current 3.5lb trigger spring with a gold colored one that is 5.5lb. It might have come with your friend's trigger, if not he needs to call GA and request one.
+1
THIS
Mr Elbowseed
09-16-12, 04:13
Crap! I meant my friend was embarrassed!:)
First thing I expect when the story starts "my friend has this problem":D
BufordTJustice
09-16-12, 04:38
Crap! I meant my friend was embarrassed!:)
Np. Still happy to help. ;)
It's the S3G trigger....I'm very confident about that.
It's not the trigger's fault per say, but rather the end user's lack of full control over the rifle that leads to "bump" firing it. That trigger is so light, smooth, and ultimately lightning fast that it's quite radical for most new users of it.
Seems to me your friend isn't paying as much attention to shouldering the rifle really soundly until he experiences a bump fire sequence.
The easiest remedy for this is to replace your current 3.5lb trigger spring with a gold colored one that is 5.5lb. It might have come with your friend's trigger, if not he needs to call GA and request one.
I have heard that are shipping with an additional spring now. Thanks for identifying it. I will reach out to them for the gold spring as I would like to try it.
My guess: free floating firing pin was hitting the primer hard enough to set off the round (commercial ammunition generally uses softer primers), when you switched to the Uzi ammo the harder mil primers prevented this.Thanks for your reply. A bunch of the guys I work with were at the show and we all bought one of these things. Everybody had a similar problem, but I didn't find out until it was a little late to take the gun back to the store. Unfortunately its now illegal here in California, so I'll just have to let it sit until I retire and move out of here. Thanks again.
This makes me wonder how many people actually take the time to read the product info and installation directions with a new product. The packaged info with the s3g states the issues with possible bump firing.
I just installed one and have no intention of switching spring if you want it its yours. Geisselle Will do it as well just an offer. There cs is second to none. I emailed them at 5 am (west coast) i had a response at 5:09 (east coast).
This makes me wonder how many people actually take the time to read the product info and installation directions with a new product. The packaged info with the s3g states the issues with possible bump firing.
I just installed one and have no intention of switching spring if you want it its yours. Geisselle Will do it as well just an offer. There cs is second to none. I emailed them at 5 am (west coast) i had a response at 5:09 (east coast).
I have no issues with the S3G. It is easy to bump fire if thats what you want to do but it is not a problem for me. I am however curious about the "other" spring. Just want to try it, thats all. If you do not want your spring I will take it. This is my third Geissele trigger and I have zero complaints about them all.
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