Update Page 3: Troubleshootin' my homegrown AR in the South Bay

[Sleepnosis]

Low feeds straight into the chamber ramps and/or round stuck halfway in magazine.

Gas Operation is 100% success
Manual Operation is 10% success

Thinking the parts weight may have something to do with it:
I'm using a heavy 9mm buffer and Young's Mfn bolt carrier

attempted excess lube: no joy
not a feed ramp problem: I checked
attempted drop test: works fine
attempted all new mags: no change
attempted different ammo: no difference

Don't have a second AR to swap parts

Fired about 100 rounds so far. Cycled about 400.

Ideas? Remedies any MV AR calgunners?

Trigger puller not an Armorer,

Thanks in Advance,
-Mark

[ghost]

have you checked your mags,since your having a feed problems?try different mags,check the follower/spring in the one youre using now.

[Sleepnosis]

Tried with all 20 brand new USGI issued mags with magpul followers and new springs. Even my singular H&K High Reliability magazine produces the same result.

single round/five rounds/full mag, same result.

Edit:
Also mangled a mag pulling open the feed lips to ease loading: no effect.

[Blue]

Do you have a different bolt carrier to try out?
ETA re-read your post, no love there. Hmm....

ETA2 I got an idea. You're using a carbine buffer in an A2 stock? Did you use a carbine spring as well? I think there's a spacer that's supposed to go in your buffer tube. Just a guess.

[GartenZwerge]

Gas Operation is 100% success
Manual Operation is 10% success

Soo it works 100% when you shoot it...?

[Sleepnosis]

When the gun is fired it completely cycles.
When I go cond. 1 by racking the charging handle is when problems start happening.

If and When I get a type one, two, or three malfunction it will lead to me completely disassembly of the upper from the lower.

cont.
instead of TRB or weapon on safe, lock bolt to the rear, remove magazine, charge (x3), insert fresh mag, problems AGAIN!

[Army]

Lose the heavy buffer. Install normal carbine buffer. The carrier is not getting up enough speed from bolt lock.

[ar15barrels]

I'm thinking that you may be MANUALLY cycling the action by pulling back on the charging handle and letting it forward.
This often causes the problem you see.

The solution is to release the bolt by depressing the bolt release on the side of the gun.
The charging handle should be all the way forward before you do this.
The charging handle bouncing back and forth within the receiver is enough to cause FTF's like pictured above.

Also, how many rounds are loaded in the mag when you get this problem?

[FreedomIsNotFree]

I know quite a few people that use the heavier 9mm buffer in their AR's with no issues. I wondering what's specific about the OP's rifle that doesn't sit well with the 9mm buffer? Also curious as to which buffer spring he is using.

[Sleepnosis]

Awesome.
Army and Technical Ted:
Thanks thats what I was thinking and y'all convinced me to pick one up.

...to the internet dealers!

[Sleepnosis]

My spring length is 10.5 inches. This is the common length. Rifle being longer.

The buffer is a black RRA 9mm

[Sleepnosis]

I'm thinking that you may be MANUALLY cycling the action by pulling back on the charging handle and letting it forward.
This often causes the problem you see.

The solution is to release the bolt by depressing the bolt release on the side of the gun.
The charging handle should be all the way forward before you do this.
The charging handle bouncing back and forth within the receiver is enough to cause FTF's like pictured above.

Also, how many rounds are loaded in the mag when you get this problem?

I understand that this is the proper way. However a manually cycled bolt shouldn't do this. Tell me this isn't normal. This isn't

Magazine has been loaded single, then five, than full to try and address this problem. With USGI and H&K.

Thanks for the help.

[Sleepnosis]

I know quite a few people that use the heavier 9mm buffer in their AR's with no issues. I wondering what's specific about the OP's rifle that doesn't sit well with the 9mm buffer? Also curious as to which buffer spring he is using.

Thats what I was thinking except I'm running two of the heaviest options right now, a stainless BCG AND a heavy buffer.

[ar15barrels]

I understand that this is the proper way. However a manually cycled bolt shouldn't do this. Tell me this isn't normal. This isn't

Magazine has been loaded single, then five, than full to try and address this problem. With USGI and H&K.

Thanks for the help.

Is it a new gun?
If so, put another 500 rounds through it to burnish the feedramps.

What receiver are you running?
Are you aware that the Young N/M bolt carrier is specifically made oversized to account for loose receiver specs?
They sometimes cause problems in tight-spec receivers.
Try another bolt carrier and I bet the problem goes away if your receiver is a snug fit to the carrier.

[ar15barrels]

I understand that this is the proper way. However a manually cycled bolt shouldn't do this. Tell me this isn't normal. This isn't

Common in new guns.
Not normal in well broken-in guns.