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Best way to pin an ALUMINUM flash hider

h34choctaw

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I'm thinking of pinning a 3" linear comp made of 7075. I'd like to cut the barrel down to 13-1/4". Would drill and pinning a rod with high-temp epoxy be alright? Or putting a steel pin with about 1/32" below the surface and Tig over? I have access to aircraft grade high temp epoxy used in the jet engine area. If it was placed on the threads and cured you would year the barrel out of the receiver if you tried torquing it and it's good to 800 deg F. Any advice?
 
Never done it, but I believe the AFT has a section stating exactly what the require to be permanently attached. Silver solder and pin of a certain depth or something like that. For the legality and risk associated, Id pull the barrel and take it somewhere. Not that you run a big risk of getting caught, but it would spell big trouble if you did.
 
Copied from ATF National Firearm Act Handbook

2.1.3 Rifle. A rifle is a firearm designed to be fired from the shoulder and designed to use the energy of an explosive in a fixed cartridge to fire only a single projectile through a rifled barrel for each single pull
11
of the trigger.
A rifle subject to the NFA has a barrel or barrels of less than 16 inches in length. | 12 inches ________|
The ATF procedure for measuring barrel length is to measure from the closed bolt (or breech-face) to the furthermost end of the barrel or permanently attached muzzle device. Permanent methods of attachment include full-fusion gas or electric steel-seam welding, high-temperature (1100°F) silver soldering, or blind pinning with the pin head welded over. Barrels are measured by inserting a dowel rod into the barrel until the rod stops against the bolt or breech-face. The rod is then marked at the furthermost end of the barrel or permanently attached muzzle device, withdrawn from the barrel, and measured.
 
Yeah....the ATF probably isn't up to speed on some of the advances in epoxy's. Will have to Tig I guess to stay safe. I've read that even that won't help with some law enforcement that don't understand that the measurement is taken from the closed bolt. Oh well. Best to keep a copy of the reg in the buttstock I guess.
 
Do not forget to make the barrel about 14 if you want a 16.25” barrrel. You will need about .75 inches of overlap for threading or sweating on. I would only consider blind pinning a steel pin about .125 below the surface of the aluminum and then weld over the pin hole with aluminum.
 
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