AR Issues

[.45Kimber1911]

Thought I'd do a little research and look up the actual numbers for you.

From the Technical Manual:
ARMY TM 9-1005-319-23&P

Action spring free length should be:

RIFLE:
11 3/4 Inches (29 85 cm) minimum to
13 1./2 inches (34 29 cm) maximum

CARBINE:
10 1/16 inches (25.56 cm) minimum to
11 1/4 inches (28.58 cm) maximum

I pulled up the same information after checking your post. Apparently the gunsmithing video that I watched on the subject from Brownells I believe is completely wrong about that part being interchangeable. My apologies Sir!

[Gun]

My first thought when I started reading this thread was that this is a carbine with a rifle length buffer spring installed. There are a lot of other good ideas in this thread to check, but when I read that the buffer, buffer tube and stock were purchased separately, it reenforced my thought of the wrong spring installed. This will also cause short cycling, giving similar results.

Just something else to check.

The OP stated he bought a set.

I'll have to check for the markings when I get home. It is an ATI Strikeforce set. I'm pretty sure it was labeled as the "civilian" buffer.

http://www.atigunstocks.com/stocks/1...rce-stock.html

[okw]

I pulled up the same information after checking your post. Apparently the gunsmithing video that I watched on the subject from Brownells I believe is completely wrong about that part being interchangeable. My apologies Sir!

Accepted. I love the Brownells videos, but you have to watch what they say sometimes. Not always completely accurate. However, there are certain springs that claim to be interchangeable.

The OP stated he bought a set.

What I meant in my original post was that the buffer, tube and stock did not come with a complete gun, they were purchased (as a set, as you mention) at a different time.

I have seen the wrong spring included with a set on more than one occasion. Just saying it's something to check.

[17CulpeperMM76]

I haven't had much time to do any research this week so far, or check out the gun.

I will have time this weekend though, and I am very grateful for all of the information that has been posted so far. I'm sure it will be a big help!

I'll report on what I find sometime this weekend.

In the meantime, please keep the info or suggestions coming if you have any.

Thanks!!

[17CulpeperMM76]

Ok, I have had a chance, finally, to check a few things.

The gas key is tight and staked.
The gas tube appears to be correctly aligned.
With an empty mag, the bolt will lock fully open.

How do I go about checking for a gas leak?

What can I check regarding the buffer tube assembly? Should I just try a different one?

[Lycanthrope]

Look for blowby and soot near the gas block. If it's misaligned and not leaking, the only way you'll truly know is to take it off and see. Then use feeler gauges to align the ports center to center.

To rule out other nonsense, find someone with a running AR and pin your upper to it and see how it runs.

Lycanruleitouteasythrope

[Hawk]

To easily and quickly check the gas block for leakage, blockage, misalignment:

1. Clear the rifle.
2. Remove the upper
3. Remove the BCG.
4. Plug the barrel at the chamber end (air tight). Several oiled patches tightly inserted all the way into the chamber with a cleaning rod should work.
5. Place you finger over the end of the gas tube where it goes into the BCG.
6. Now for the fun part! Wrap your lips tightly over the muzzle and blow a moderate pace (like bowing bubbles with a straw in your chocolate milk).
7. Check for leaks at the gas block. You could use a little soapy water and check for any bubbles forming.
8. Now lift your finger from the gas tube about a 1/4" and blow again, you should feel a stream of air (similar to the same amount of air if you were blowing through a coffee stirrer straw).

Report back your results.

[Son of a gun]

To easily and quickly check the gas block for leakage, blockage, misalignment:

6. Now for the fun part! Wrap your lips tightly over the muzzle and blow a moderate pace (like bowing bubbles with a straw in your chocolate milk).

when performing be sure no one can walk into room makes for an odd encounter...


on a serious note

to make sure it is not the mag
DO THIS OUTSIDE YOU WILL BE FIRING
Load a round
drop the mag
point in safe direction place finger on lower part of bolt hold open (engage side not release) while pressing on it fire the rifle
if the bolt is on the hold open it is the mag
if it is not on the hold open gas block alignment, gas tube alignment, bad bolt gas rings...

i take it you can pull the charge handle all the way back and lock it on the bolt hold open (make sure no rifle buffer/spring got in there)

[wheeling365]

I didn't see this mentioned. Check the gas rings. If they have the openings all aligned it creates a gas leak in the system and will short stroke the gun.


I'd also try a different brand of ammo just to rule it out. PMC is decent stuff but its possible you just got a batch that is loaded light on powder.

[cpio]

This might sound a bit odd, but I would make sure that the gas tube is properly indexed. Check the tightness of the bolts or screws holding the gas block onto the barrel (if you have an aftermarket gas block) and check the roll and taper pins if it's an A2 front sight base. Also, DO NOT put your mouth over the muzzle of a firearm. Use an air compressor or something.