What's Wrong With My Rifle?

[Catskillkid]

So I recently completed a new AR build and finally had a chance to take it out yesterday. I'm less than enthused.

Began shooting (5.56 NATO 55 grains) and while it seemed to cycle ok the rounds were not exactly ejecting. Basically just plopping out of the port and falling on my shooting bench. After about 10 or so rounds it got worse to the point where it will jam after firing off only one round.

I took it apart, looked at the bolt carrier group (Anderson Manufacturing. Have one in another build that works flawlessly) and seemed ok. Barely fired but stripped, cleaned and lubed it. Tried a different magazine. Still the same issue.

Any ideas?

 

[dsdmmat]

Not enough gas pressure or too heavy of a buffer, buffer spring.

 

[Eddie Gunks]

Lube bolt.

Check gas block alignment. If good chamge gas block. (If anderson aluminum gas block throw it away, buy new one)

What color buffer? Black is bad. Gold is good. Replace if not gold colored.

Let us know.

 

[Uzi]

Probably a gas block issue.

 

[Catskillkid]

Bolt is adequately lubed (as far as I can tell).

Buffer is a Tapco buffer. Same as in my other build. No issues there.

Had a Geissele handguard with a low profile gas block. Thought I installed it properly but maybe not. How do you tell?

 

[ManrisFrack]

Take it off and look at the soot ring on the barrel. It should completely encircle the gas port.

Originally AR-15's had a hand guard end cap that went between the gas block and the shoulder on the barrel. A lot of barrels and gas blocks are still cut to accommodate an end cap. If your rail is a free float and your gas block is right tight to the shoulder, that may be your issue. Looking at the soot ring, it should be pretty obvious. If it needs a gap between the block and the shoulder, I think I recall that it's about 0.020".

 

[thegatman]

Gas issue.

 

[meketrefe]

It is not hard to figure out what is wrong but you have to go step by step.
The first most common reason is the gas rings might not be properly staggered together.
This can happened at any time. If this is compound by an already under-gassed system then you might experience short stroking.

Follow the gas ....
A) Proper gas port pressure. Is the gas port the proper size? Do you have a mid-length, rifle or perhaps a carbine?
B) Proper gas block pressure. Is the gas block properly aligned and it is not bleeding out gases? Clamp type of steel are the best
and a good trick is to put a drop of blue locktite ahead of the port around the tube and perhaps another drop around the port
if you have a set screw. Aluminum set screw are the worse as aluminum and steel dilate at different rates.
C) Proper gas tube pressure. The tube must be the right one and seal well with the gas key.
D) Bolt gas pressure. Check out the staggered rings. They also sell coiled rings although there is not a huge need for those.
E) The bolt should be striped down and cleaned from machine particles before using. Any shavings might interfere with the ejector
plunger or spring and it is also an opportunity to do a good cleaning. Extractor needs to be snug but not too hard. The o ring is
not always necessary if you have the proper spring.
F) The trigger hammer might have enough tension and proper shape for the bolt to start moving w/o huge resistance.
For this the carrier needs to be shrouded and the edges should be smooth with a smooth finish. This is not always the case
with spring with way too much force and parts not properly polished.
G) The bolt should rotate freely in the cam and give some clearance after starts moving to when it starts to rotate.
It is normal to have a bit of for resistance with new parts as they need some conditioning but this should be lubricated
and move fairly easy. You will experience more resistance when charging the rifle with the handle than the force the bolt
needs when pulling away in the carrier because it is design to open easier that way.
H) The bolt lugs should not touch the magazine lips. Any frictions here should be inspected and see if the lips are bent or
something else is going on.
I) If a fully loaded magazine has excessive tension then one or two coils could be cut to improve reliability. Sometimes these
are way too stiff and like the trigger hammer do not help with the cycling. Cycling should be smooth and it is more a matter
of timing more than a mater of brute force.
J) A heavier buffer will be more reliable on average but not really necessary if all the other things are properly inspected.
K) Same thing with the buffer spring. Standard spring should work fine w/o the need for anything else special.
L) Your buffer tube should have a way to bleed the air out on the back. Inspect your buffer tube and make sure you have
a way to bleed the air.
M) Make sure there are not any other interference, frictions, parts hitting each other in the tube or anywhere else.

All these things can be easily inspected and debugged one at the time. Everything that happens when fast cycling many
times happens also slowly when you closely inspect with some dummy rounds. So go to point A, make sure you have
the proper gas port size and then work down the list. Also keep in mind that a rifle might run fine with lake city
and then when you switch to lets say PMC bronce 223 the rifle will not cycle. There is close to 300fps difference
in speed and corresponding lower pressure of the ammo so for some commercial ammo is why one might need to
start with a good porting job. Carbine porting tipical in the M4 style is the most problematic and should be avoided
but it doesn't have to be always a problem.

ARs like to run clean and wet (lubed) unlike AKs that run better dirty and dry.

I hope this helps.

 

[Mosinitis]

Does the bolt locks back on empty magazine?

 

[Deplorable Me]

Is gas tube, damaged, pinched or internally blocked? Metal chips from factory in tube? How about a tube cleaner?

 

[Eddie Gunks]

Bolt is adequately lubed (as far as I can tell).

Buffer is a Tapco buffer. Same as in my other build. No issues there.

?

Just because it works someshere else doesnot mean it is not broken or bad......so again, what color is the buffer?

Fwiw imo tapco shit is exactly that.....shit

 

[Eddie Gunks]

Geiselle gas block?

Who made the barrel?

 

[Catskillkid]

Geiselle gas block?

Who made the barrel?

Stag

 

[Eddie Gunks]

......so again, what color is the buffer?

Geiselle gas block?

Who made the barrel?

So hard to help....... how about answers to the above questions?.......

is the barrel and gas block stag?

 

[Bananabandit]

Its an AR. Youre welcome

 

[Catskillkid]

So hard to help....... how about answers to the above questions?.......

is the barrel and gas block stag?

Sorry, barrel is 16 inch crowned barrel by Stag

Gas block is built by Geissele. It's this: Super Gas Block. It came with the handguard: Super Modular Rail MK8 M-LOK
https://geissele.com/super-modular-rail-mk8-m-lok.html
This is the buffer tube assembly I got (purchased Mil Spec). Looks like it's gold (not black). TAPCO WEAPONS ACCESSORIES AR-15/M16 BUFFER TUBE ASSEMBLY | Brownells

I'll have some time this afternoon I'll try to look at the gas block to make sure it's lined up properly.

I realize it doesn't necessarily mean anything but for my first build I used mostly the same parts (different gas black/handguard) and had zero issues.

 

[Eddie Gunks]

^^^^^hhhmmmm. Sounds like armorer's error.

All those parts should Not give you issues.

Try realigning the gb and get back to us.

 

[turbobike]

Make sure the gas tube is not obstructed..blow some air through it. I had a PSA tube and gas block that was plugged with some metal shavings...

 

[Catskillkid]

So took the rifle apart and I'm more convinced then ever it's a gas block problem. When I removed the handguard the block was loose (I remember it being tight when I put it on). Some photos are below:

Here's the barrel minus the gas block. Slid right off without having to undo the screws on the bottom (see pics below).



Here it is "installed" properly (or so I believe). Currently it's just sitting there without the screws being tightened. Figured I wait for feedback before doing any other work.



A top view of the gas block.



And here is a pic of the bolt carrier group. Looks ok to me but more informed and experienced eyes might be able to see if there are any defects.




So what do you all think? Is it a gas block problem? That's my feeling as it was loosed when I took the handguard off. Not sure how to correct it. I dimpeled the barrel and everything so the screws could sit in it well. My other build has a clamp on style gas block but I'm worried that only the proprietary Geissele gas block will work with the handguard. Anyone have experience otherwise? Any advice overall?

 

[Robin]

Looks like you found the cause of your malfunctioning, now you have to find the cause of the malfunction that caused the malfunctioning. Why did it to come loose?
Robin

 

[SteyrAug]

Or you could just buy a quality AR to start with.

 

[Catskillkid]

Looks like you found the cause of your malfunctioning, now you have to find the cause of the malfunction that caused the malfunctioning. Why did it to come loose?
Robin

I really don't know what caused it to come loose. I put dimples on the barrel per the instructions and everything. Perhaps they weren't dimpled deep enough? The screws weren't put in correctly or all the way? I'm kind of at a loss.

 

[meketrefe]

It seems you have some bleeding but perhaps not so much.
A drop of blue locktite ahead of the tube should help although over time
the carbon itself will seal it.
You might have compounding issues.
What is the size of the gas port?
The list I gave you should give you a step by step guide.

 

[meketrefe]

Or you could just buy a quality AR to start with.

This is not helping anyone on this thread.
You seem to like trolling way too much.

 

[NYGuns]

Or you could just buy a quality AR to start with.

No need for this or these type of comments.

 

[Calculon]

Blue loctite on screws when reinstalling gas block.

 

[GUNSICK]

Definitely looks like your problem. You can see where the gas was escaping by the marks on the barrel.

 

[GUNSICK]

Or you could just buy a quality AR to start with.

Or just post a pic of one off Google images and claim you own it.

 

[SteyrAug]

Or I could lie about my background and welch on a bet I accepted LIKE YOU !

 

[Catskillkid]

Thanks for the advice everyone (well almost everyone). I'm thinking the issue is the alignment of the gas block/it coming out of place for some reason. I tried realigning it and drilled the dimples in the barrel a little more and really tried to get the screws down tight this time. It's reassembled and ready to go though I don't know when I'll be able to test fire it again (going to be pretty busy the next two weeks). If I have a spare moment one day after work I may try to fire off a few rounds to see if the issue is resolved. If not, you know I'll be coming back here.