BCG = Double tap

[golfish]

Double tap is the issue and the problem has been narrowed down to the BCG. What should be looked at.

[Rhyyke]

what is double tap?

[GM4spd]

what is double tap?

Good question
Another home build doubling? ie two shots for one trigger pull.

[SUBSONIC]

Double tap is the issue and the problem has been narrowed down to the BCG. What should be looked at.

cHECK TO SEE IF YOUR FIRING-PIN IS OUT OF SPEC, IF THAT IS WHAT YOU THINK IS WRONG..... however, it is more likely that you have a bad disconnecter spring or it is out of spec....buy a good one, mil-spec(Colt,etc,etc) cheaper than a new face or being blinded when the gun fires out of battery.

I have found in the past it's usually the fault of 1(or more) of 3 parts for this dangerous situation to occur:
1) Hammer-bad
2) disconnecter--bad
3) disconnecter spring-bad

[Whiterabbit]

My bet is the disconnector spring isn't there at all.

If it's truly in the bolt, I don't know.

I'm in for the answer. I'll be interested to know how the BCG could do it.

[IrishJoe3]

How'd you narrow it down to the BCG?

My experience is double taps caused by
A) light trigger/short reset, and essentially having a bumpfire.
B) Missing dis-connector spring.

[Bansh88]

My boss bought a WASR years back. Thing would fire off randomly with a trigger pull.
Bad spring.

[joker70]

Are you sure that it's not an out-of-spec hammer or disconnector? If it goes bang when you pull the trigger and bang again as you reset, I'm betting its one of the two.

[jeremyro]

Could the firing pin be stuck protruded? I would think that would cause it to fire the whole mag, but worth a look. You really need to give more information. I almost can't see how it could be the BCGs fault unless you have something SUPER out of spec or dirty.

[CandG]

As well as a completely missing disconnector spring, my understanding is this can also happen if that spring is installed, but upside-down. It's a tapered spring, and the larger end needs to sit in the trigger recess.

Also, If this was an 80% lower, check that the locations of your trigger group pin holes are correct.

It's not very likely to be a problem with the BCG causing this. Almost for sure something related to the trigger group.

[golfish]

Thank you all for the replies.

Back to the topic, double tap = BCG. So we would look a the firing pin and move on to ?

Lets say its always the first 2 rounds, and again, we are only looking at the BCG.

[LeadFarmer74]

Thank you all for the replies.

Back to the topic, double tap = BCG. So we would look a the firing pin and move on to ?

Lets say its always the first 2 rounds, and again, we are only looking at the BCG.

First maybe explain the problem? You pull the trigger and the gun fires 2 rounds? So after the first shot it cycles and automatically fires the second round then cycles and loads the third but doesn't fire? I'm can fathom how it would be the bcg. I would think it would be trigger related.

[HK Dave]

Like everyone said... whether you think we're off topic or not, it's really not likely it's a BCG issue.

[Whiterabbit]

Thank you all for the replies.

Back to the topic, double tap = BCG. So we would look a the firing pin and move on to ?

Lets say its always the first 2 rounds, and again, we are only looking at the BCG.

OK, so assuming by double tap, you mean you get two rounds fired for every trigger pull, and again assuming you solved the problem by replacing the BCG and the problem went away, then we all can move on from the off-topic nature of our very strong suggestions to look at the disconnector.

It would be very helpful to get confirmation of our assumptions, because the statement "double tap = BCG" is not descriptive enough for us to understand the idea of double tap being two rounds fired for every trigger pull (we need that confirmed, because it's not the terminology we typically use) and confirmation that it's absolutely in the BCG, ideally due to existing troubleshooting (so we don't suggest something you've already done).

Anyways, making the two rash assumptions that you've already done actual troubleshooting (and not just a thought experiment) and nailed down the issue into the BCG, getting two rounds to fire is unusual. I would look at the firing pin being sticky, it should be free floating. If it stuck out, you can fire going into battery. You say BCG, but in that case I might also look at ammo if you have not partitioned that. thin primer cup or high seated primer causing a slam fire?

After that, I'd start a thought experiment about how the cam of the bolt could cause the firing pin to extend forward and put on my wacky cap because now we're getting into weird territory.

THAT IS OF COURSE assuming that my assumptions are correct (that by double tap you mean two rounds fired for one trigger pull, and that you have done real troubleshooting already to nail down the BCG as the culprit, not just imagining that it has to be the BCG)

If my assumptions are wrong, this whole post will not be helpful.

[Whiterabbit]

can you look at your brass? does the fired brass look or mic unusual? or are they perfectly fired brass? primer sticking out? shoulder unusually far forward? primer indent look odd? Or are they perfectly fired?