AR15 Barrel Seating Depth Problem & Fix – Grey Ghost Precision

For those who dont see the reason to notch the shims, please look at how an ar barrel extension seats in a AR upper receiver. The index pin in an AR barrel extension has to seat into a notch in the upper receiver. When you put a shim or shims in between those two parts you have to remove a piece of the shim to clear the index pin.

This "fix" isnt how you normally use AR barrel shims. Normally the shims go between the barrel nut and barrel extension to time a barrel nut.

In this case a shim was needed to push the barrel forward, this it has to be clipped to clear the index pin.

Nice to see fixes for issues you've never even had, my barrel nut wasn't getting tight on my upper until the last half turn and thought I would need to use a shim or two, but thankfully the last half turn it got tight and everything's working fine, even though I probably torqued it to about 60ft lbs

What happens to the gas tube length?

Hey I have a GGP Receiver set and the hard part I've run into with the upper is installing the barrel because it's thermal fit. I sent my upper to them for another reason and they were nice enough to install the barrel for me but would really like to see the best method to install and remove a barrel this way. If you need an upper to do this I can send you my GGP Upper that already has a barrel installed. Thanks

When he opens the Vice and it hit’s steal to steal

The more I watch your videos, the more I’m scared to death that any one of my AR’s could have a problem, but at the same time, it’s comforting to know what kinds of potential issues to look for.

Still the greatest rifle channel out here though! 🤘🏽

Excellent ! Thanks for sharing the knowledge.

Thank you

Fascinating

What about if the barrel doesn't seat far enough? So the opposite of this issue. I have a new barrel and upper and when installed, there's a larger gap between the upper feed ramp and the barrel feed ramps, when compared to my other uppers.

Thx for the knowledge. I would take your class if it was in driving distance. But I live in gunsmith no man’s land. You all I got! When we lost Tony bend on M1A info I was beside myself. Please don’t leave us cause of YT👍

On the flip side, if the barrel extension comes up short, the carrier will hammer, and ruin, the receiver, right?

Very nice fix Chad , thanks as always , for sharing !!! ✔️

As you are constantly gauging, can you give us the correct dimensions for measuring the threaded portion on the upper receiver? I personally have never “faced” an upper receiver and never plan to. Would be nice be able to just measure and accept or reject.

That top corner of the upper near the threads looks like it got damaged. After the shims were installed there looks to be a crack in the anodizing. Did the upper fall off the table?

Had this same issue once. I remedied it in the same manner. Good vid.

Nice!

I had this exact issue on a completed upper I bought. Couldn’t find a single bit of info on it until this. It also caused really inconsistent shots/ bad accuracy as well until I switched to a different upper receiver. Thank you for sharing!

Why are notched shims required, wouldn't regular shims work just as well?

I wish you had flipped it around and let us take a look at the position of the index pin.

Thanks for sharing Chad.

Thank you Sir.
Happy you are making vids.

The difference between an armorer and a gunsmith. Well done.

I recognized that upper right away from a recent build I am working on. Same issue! I used shims to fix it like you, but now the bolt carrier doesn't align with the rear of the reciever. Did you notice that problem with this fix?

This is one reason why I stick with BCM uppers or any other high quality upper. Nice fix.

So was the issue likely the upper, or the barrel? I know we cannot say for sure, but folks who have encountered this problem before, which part is more likely to be the issue?

What are these shims called and where can i get some?

👍😊 I like fixen stuff well it be I’m cheap 🤷‍♂️ . 😁

Very interesting and informative! Thank you for sharing!

Thanks!

Just outstanding. I enjoy these videos a lot. Thank You for your time.

a couple of years back the procedure of truing and lapping the ar15 upper receiver at home was the "new thing" that all ar owners should do…and i saw alot of barrel extension over hang.

some were fixed with a shim, maybe two. in one case i needed a 1/4" thick custom washer.

Awesome videos. Thank you

I would add don't line up the notches if you need more than one shim, space the gaps like rings on a piston. I have only had to do this one time, I didn't cut a notch out of the shims, I simply cut the shims in one place, slide them on the extension, at the pin simply open the cut and "screw" it on the extension around the pin. The video is a good reminder to check for barrel extension overhang or being short in the receiver.

Thank you Chad

I have an upper with the opposite issue.. the receiver threads are a couple of millimeters too long…

I used this this same method on my last two builds. Worked great! Accuracy and function were not affected at all.

That was a Friday at 2:50 cut upper. 😊

Wonder how many more of those uppers are out there?

Does it matter if the shims are steel or aluminum shim stock ? Also does it matter if the shimstock is split or completely round? Also could you turn the needed shim to outside and inside diameters by the gap lenght needed plus a .010 crush allowance for barrel nut torque.?

I hope there's a longer video ,this was like an appetizer . Is it a Youtube thing,you can't show gun repair in more detail?

I wonder how many over enthusiastic true the face of the reciver people have created this issue.

Could this fix potentially cause accuracy issues?

Audio is patchy when I watch it?

I don't understand why you don't show who the manufacturer is. If manufacturers are making subpar or dangerous products, wouldn't you want consumers to know? Thumbs down for not highlighting the upper manufacturer.