A Tale of Two Crush Washers, or Two Crush Washers One Barrel, and other AR oddities

[cmshoot]

When I started to pull the upper receiver apart, I found that the crush washer was installed backwards.

The barrel nut was so loose that there was play in the barrel.

The gas tube roll pin was not driven completely through, and the proud end was peened and mushroomed over.

I installed a new gas block and gas tube. The new gas block had a nice snug fit to the barrel journal.

 

[cmshoot]

The receiver extension was 1 revolution shy of being screwed into the lower receiver far enough. The extension was barely overlapping the buffer retainer, and I guarantee that eventually that buffer retainer would launch into the gun.

 

[cmshoot]

The interior of the blue VeriForce receiver extension was the roughest by far that I have ever felt. I supplied a new milspec receiver extension, a BCM receiver end plate with QD socket (customer request), and used the existing castle nut. Castle nut was torqued to 40 inch/lbs and the receiver end plate was staked twice.

I replaced the buffer spring with a milspec one, and the janky buffer with an H2 buffer.

 

[cmshoot]

Over-torqued, just a bit.

Verify your “Armorer”. Just because they work behind a counter doesn’t mean they know what they’re doing. At least a third of the fixes, corrections, and rebuilds I do were started at another shop.

Barrel over-torqued to the point that the barrel index pin tore into the upper receiver. This allowed the barrel to clock slightly, so that the bolt did not want to go into battery. That was the issue that brought the customer in.

Upon disassembly, I found the Seekins steel barrel nut was cracked in two places.

The muzzle device was installed with a backwards crush washer, but was not over-tightened. When I went to remove it, the barrel extension spun off the barrel.

This last was a combination of factors, and was not solely the fault of the “builder”. I’ve no idea what brand barrel this is, but it was nitrided before the barrel extension was installed. This could easily cause an issue where they don’t want to stay together, but I’m fairly positive that if the barrel nut had been torqued properly, the extension would not have backed off.

 

[BigMike]

Good googly moogly! Sounds like someone was torquing head bolts! The barrel pin cut into the upper, cracked barrel nut ( personal opinion strike anything is trash) and the barrel extension spun off!

I don't understand, with the availability of information on the internet, how some things get messed up so badly. I mean installing pins can be a real pain and sometimes they split, springs and detent get lost, but torqued fastners?

 

[cmshoot]

Good googly moogly! Sounds like someone was torquing head bolts! The barrel pin cut into the upper, cracked barrel nut ( personal opinion strike anything is trash) and the barrel extension spun off!

I don't understand, with the availability of information on the internet, how some things get messed up so badly. I mean installing pins can be a real pain and sometimes they split, springs and detent get lost, but torqued fastners?

Nothing was Strike Industries. The barrel nut/rail is Seekins Precision, and is good stuff.

 

[greg vess]

Don't they use a torque wrench? I mean that Barrel nut is a pretty standard size for the most part and if it is kit specific they usually supply a special tool that has a cut out for a torque wrench to be used to tighten the barrel nut. Isn't there suppose to be a little lube on the threads as well or did you clean it up for pics?

 

[greg vess]

I believe the correct lube for that is Aeroshell 64/ 33MS on the nut and some on the extension between the upper receiver and extension. It's what I use anyway if the barrel is stainless especially.

 

[fast306stang]

Nothing was Strike Industries. The barrel nut/rail is Seekins Precision, and is good stuff.

Any insight or opinions on the new Sig stuff breaking that's been floating around the internet? Broken lugs on the uppers and broken barrel ends from trying to remove flash hiders? My mind is blown but I don't have the answers...

 

[cmshoot]

Don't they use a torque wrench? I mean that Barrel nut is a pretty standard size for the most part and if it is kit specific they usually supply a special tool that has a cut out for a torque wrench to be used to tighten the barrel nut. Isn't there suppose to be a little lube on the threads as well or did you clean it up for pics?

I doubt a torque wrench was used, or any sort of proper procedures followed.

Seekins doesn't supply a tool. The barrel nut uses a 1 1/4" wrench.

The instructions that are shipped with every Seekins rail, and are also available on their website, clearly list the torque specs. In this case, they were ignored.