Who is best pinning&welding a Colt 14.5 M4 Barrel to 16.0? I got a new Colt 14.5 M4 barrel and need to make it legal 16.0 for my 6920.
Steve at ADCO.
but it is easy to do yourself if you have a drill press and access to a mig welder.
How big does/size the pin have to be and how deep to drill into the barrel?
Most people use a chunk of coat hanger as the pin, so your pin diameter is pretty small (about .090" IIRC). Make sure you have your upper completely assembled as once the flash hider goes on you cannot install your gas block/FSB. Drill through your flash hider/brake fist, then clean up the threads if necessary. Next install onto your barrel making sure you time the muzzle device correctly onto your barrel. Then vise it into your drill press and JUST BARELY drill into the barrel, we’re not taking much here just a nice little indention. Insert your pin ensuring it is flush with the top of the hole. Make sure you wrap the surrounding area with tin foil or duct tape so no slag sticks anywhere. I then used a wire brush dremel attachment to clean the top of the pin and the surrounding area. As far as welder settings I used a MIG with flux core wire, set to amperage A (out of A-D) and a wire feed of about 2.5 or so. You don’t want a lot of penetration here, just enough to melt the top of the pin to the muzzle device so I used a 3 second buzz then stopped, let it cool, wire brushed it and checked my weld. It took 2x 3 second welds to finish. I then filed and cleaned up the weld, then applied a little touch up and voila it is done. On a scale of 1 - 10 of welding difficulty it’s maybe a 2. Still though remember to practice practice practice, even if your a skilled welder it is easy to F this up. When you think you’ve got it, practice some more. It’s not that hard if you have access to a MIG welder and a cheap drill press. Good luck!
I went with a 3/16" hole and roughly 0.060" down from the top of the threads if I recall correctly. I just threaded my FH on to spec’d torque, touched off on the middle of the FH, set zero from there and drilled down 0.250" exactly. This was with a YHM Phantom FH. Seems plenty strong.
If your in AZ then Go to Ken Elmore at SAW. He pinned and welded a Colt 14.5 M4 for me. It is the cleanest installation I have seen. You need magnification to see the weld.
My Bushmaster has a 14.5’’ barrel with the pinned and welded Comp (ban era). I contacted Bushmaster about having a Phantom flash hider installed and they recommended…www.adcofirearms.com.