Bang Bang Click

[cjd3]

After todays range trip, I had a whole slew of malfunctions with my rifle build. I will try to get some photos up later this evening, but here is what is happening:
First off, I'm having a hard time seating the magazine with the bolt closed. I have 3 G2 Pmags, happens to them all.
Secondly, if I load the rifle with bolt open, I will be able to shoot 2 rounds. The 3rd one clicks. Upon extraction of the bullet, small to moderate effort to pull the charging handle back, the brass has 2 gouges on the top and the primer isn't touched, so I can assume I am not achieving full battery. I'm thinking this is from the bolt closing on top of it while chambering the last round that fired.
One of my malfunctions jammed a round in the feed ramp (M4) resulting in bullet setback.
So I've got a bit of a mystery for me here. This never happened with my factory Stag.
The lower is a Blemished San Tan Tactical with a CMT UPUR-1LH on top. There is a little wobble from the STT lower that doesn't exist when the upper is mated to one of my other forged lowers. I do have an adjustable gas block, which I will open all the way up next session. I am using a heavy buffer, and the barrel is an 18" SPR with a rifle length gas tube.
Thanks for the help. Once the kids are fed and in bed, I can get some pics up.

[Thompson]

Seating the mag on a closed bolt - fully loaded mag? If so, that's not uncommon.

Maybe this is a stupid question - did you check headspace?

[Farva]

Seating the mag on a closed bolt - fully loaded mag? If so, that's not uncommon.

I agree. I have this issue as well on occasion, just gotta give the mag a love tap

[WHSmithIV]

I agree. I have this issue as well on occasion, just gotta give the mag a love tap

My magpul fully loaded mags don't like to seat fully in with my Phase 5 billet lower either. So, I just slam them in and that works. My hexmags work better than that for insertion and so do my two Israeli military surplus mags.

As for the bang, bang, click... that could be a few things. How many rounds have been fired so far? Where are the gouges on the casings? With rifle length gas and an 18" barrel there's no need to bleed gas off at the gas block.

[cjd3]

This rifle has around 100 rounds through it. This is the first time I've had this much of a problem, and there was little change from my last trip to the range.
So the Pmags are loaded to 29. But fired 29-28, click on 27. Clear, free 26-25, click on 24. I thought I gave it a good love tap, but apparently not.

[Farva]

you said on the clicks there was no primer strike correct?

[cjd3]

you said on the clicks there was no primer strike correct?

Yup, or a very light tap. I'm thinking it was just millimeters out of battery.

[Farva]

ammo issue maybe? maybe got a bad batch.

[mustangfreek]

ammo issue maybe? maybe got a bad batch.

Im not a whole lot of help , but have had some troubles lately with my crap that had and still..Anyways

Curious what kind of ammo factory stuff? or reloads?

Bcg and bolt?

got any other mags to play with? some GI's, gen 3's , lancers something else to try for the hell of it?

Im just spit balling

those are some good ones, ramps crushed them suckers..

[Farva]

Every now and then on a new build Ill have new feed ramps/ new extractor scratch some casings until they break in but nothing close to this

[Kopis]

i had this exact issue with one of my previously reliable builds. It started after i installed a CAA Completely Collapsible Stock (like the Troy PDW stock). It had a proprietary BCG with integrated buffer and a provided spring. I ended up going back to a minimalist stock and JP SCS and havent had an issues since. I would look at the gassing or buffer/spring. I think i could have gassed mine up more but i just cant stand a finicky gun.

[Former11B]

Those two little pinch marks on the brass are really suspect. And that's from just inserting the mag? Is the bolt forward at the time? It almost seems like it's out of battery and the brass is hitting the lugs on the bolt itself

[Stone]

That is the bolt dragging across the round. Back your mags down to 25 rounds and see if it will cycle. Rifle well lubed? On new builds I hand cycle them at least 50 times to get things mating together. Since the bolt is dragging it's slowing it down and not going into battery on that third round. Definitely open up that gas block as well.

[Jerry R]

Are these reloads?

Look at the shoulder set-back - the ridge formed right at the beginning of the taper down to the neck. I have not seen a rifle set the shoulder back like that - bullet set-back yes, but not the shoulder. They appear to be reloads done with the sizing die set incorrectly; i.e., the die is literally crushing the case shoulder. With that wrinkle, they will not chamber easily, if at all. They would stop short, eliminating the possibility of proper primer strike.

Compare these to rounds out of the same batch that have not been chambered - how does the shoulder look? If the rounds are factory, and the shoulders on un-chambered rounds look good, then pursue options stated above.

The parallel creases in the case body look like lug impressions - either the rounds do a nose up, don't chamber, and the bolt carrier forces the bolt lugs into the case, or the nose fails to chamber and the carrier jams them into the barrel extension lugs. Can you tell if those two creases are on the top of the case when you eject them, or on the bottom of the case?

Based on your loading of the magazines, are the "clicks" always when feeding a round from the same side, or does it happen when feeding from either side? Perhaps barrel extension mis-aligned??

[alamo5000]

The lower is a Blemished San Tan Tactical with a CMT UPUR-1LH on top.

Which BCG are you using?