View Full Version : What material (type of pin) should I use for permanent muzzle brake pin?
As the title says. What should I use as the pin to permanently pin and weld a muzzle brake on?
Thanks, NYH1.
Do you know the material the muzzle brake is made of? I would try to match it as best you could. I'm not familiar with weldability of different SS alloys but if the brake is SS I would look for SS round stock of a suitable diameter. Same thing for carbon and other alloy steels. I believe many commercially available precision dowel pins are are a low alloy, high carbon steel like 1080, 1085, etc. and they would weld ok. You can also find precision ground or cold rolled round stock in similar alloys in the 10XX series. A word of caution though - if you weld onto a high carbon steel there is a possibility some of the carbon will diffuse into the weld puddle and make it very hard to drill later on if you needed to remove it. You could always grind it though.
To be honest it probably doesn't matter all that much. You could even use a piece of a drill bit shank. The only thing I'd want to watch out for is anything ugly happening to your weld puddle because of a funky pin. You don't really need the weld to fuse with the pin either, just cover it up.
I just used the piece of drill bit that I used to drill into the barrel. Drilled the hole and then used a dremel to cut a pin out of the drill bit.
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It's a Colt M4 SOCOM barrel so 4150 chrome moly steel or something or other!
A2 type muzzle device.
I never thought of using the drill bit.
NYH1.
I have always used a portion of the shank of the drill bit I used to drill the hole. Perfect fit.
Role pins are fine too, the weld will flow into it.
Lot's of people who do this just clean the parts and hard solder silver braze with a TIG in a flameless way in a purposely sloppy way to assure ATF compliance for presentation with minimal effect on the base barrel for compliance. It fits within ATF's requirements unless something new has changed.
Sancho Panza
07-07-17, 21:45
BCM A2X was what I used. It came with a pin, & was pre-drilled.
1018 mild steel.
Why make life difficult if you decide later to change muzzle devices . . .
christopher.dow
07-08-17, 11:03
I saw another technique and wondered if it was acceptable:
In this case, the muzzle device had a threaded hole. The gunsmith drilled a hole in the barrel, then ran a screw through the threads and into the hole. When it bottomed out, he torqued the screw until the head broke off. Next, he cut off most of what was sticking out of the hole with a dremel, and finally ground it down and hit I with a wire brush.
It really looked like a weld and the muzzle device was clearly going nowhere. However, no welding was involved.
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I think to be compliant it has to be pinned and welded or pinned and silver soldered with specific solder. TIG welding is easy for us so that's the way I'll do it.
NYH1.
I have always used a portion of the shank of the drill bit I used to drill the hole. Perfect fit.
Role pins are fine too, the weld will flow into it.
I've done the same (simply cut a piece from shank of Drill bit) on a couple builds.
BCM A2X was what I used. It came with a pin, & was pre-drilled.
BCM makes it easy
1018 mild steel.
Why make life difficult if you decide later to change muzzle devices . . .I wouldn't expect that to prevent it from being twisted off if you tried hard enough.
Do you know the material the muzzle brake is made of? I would try to match it as best you could. I'm not familiar with weldability of different SS alloys but if the brake is SS I would look for SS round stock of a suitable diameter. Same thing for carbon and other alloy steels. I believe many commercially available precision dowel pins are are a low alloy, high carbon steel like 1080, 1085, etc. and they would weld ok. You can also find precision ground or cold rolled round stock in similar alloys in the 10XX series. A word of caution though - if you weld onto a high carbon steel there is a possibility some of the carbon will diffuse into the weld puddle and make it very hard to drill later on if you needed to remove it. You could always grind it though.
To be honest it probably doesn't matter all that much. You could even use a piece of a drill bit shank. The only thing I'd want to watch out for is anything ugly happening to your weld puddle because of a funky pin. You don't really need the weld to fuse with the pin either, just cover it up.Use carbide and you can get it off. Drilling it is going to be difficult at best with a small weld on 4150.
I saw another technique and wondered if it was acceptable:
In this case, the muzzle device had a threaded hole. The gunsmith drilled a hole in the barrel, then ran a screw through the threads and into the hole. When it bottomed out, he torqued the screw until the head broke off. Next, he cut off most of what was sticking out of the hole with a dremel, and finally ground it down and hit I with a wire brush.
It really looked like a weld and the muzzle device was clearly going nowhere. However, no welding was involved.
Sent from my iPad using TapatalkI wouldn't trust that to be legal. It doesn't take very long to weld over the top.
Thanks for the reply's.
What diameter drill bit should I use?
NYH1.
A piece of inconel welding rod works just fine.
I did 'em with 1/8".
I haven't dealt with inconel rod but most welding rods are relatively soft, and I'd rather have the pin hard (so that, if they try to remove it, it doesn't deform and let it move).
I use 3/32 or thereabouts.
There's a few good reasons why some would tend to prefer an application that induces minimal heat with the issues associated with that and maintain ATF compliance.
I used an Allen screw. I drilled and tapped the flash hider and drilled an aligning hole into the end of the barrel. I screwed in the Allen screw until it was tight (not farmer tight) and then I filed off the portion where the Allen wrench inserted and made it smooth. I do need to touch it with a welder at some point in the near future but otherwise it can't be removed without drilling it out. I guess everyone has their method.
kwg
In the USA, you need to be ATF compliant with that when required. There are methods that can be compliant with that while inducing minimal heat into the barrel to meet that requirement.
Randall of AR15Barrels.com pointed out that using a set screw will make it much harder to remove in the future if you decide to do so.
Tigwelder1971
07-29-17, 22:39
BATFE does not specify pin material.
BCM A2X is a foolproof setup including a predrilled MD and pin.
ADCO sells a spacer that is awesome, when used with a std A2, OAL length is gtg on 14.5".
Or go 14.7" and standard.:)
I use 17-4 SS pins( available at my shop) in 1/8" diameter. And of course, I spot weld mine using TiG.
BATFE compliance is both pinned/welded or silver soldered to the barrel per requirement.
Yeah, I'd much rather go 14.7 vs 14.5. It means you can use almost any muzzle device you want.
Tigwelder1971
07-31-17, 21:17
Yeah, I'd much rather go 14.7 vs 14.5. It means you can use almost any muzzle device you want.
Roger that. I have that in the plans for my next build. I dont mind the A2X, but the 14.7" looks cleaner, IMO.
I like the VG6 Gamma, and think that the normal version looks significantly nicer than the EX - for some reason they put the extra length in the back portion, rather than extending the functional portion.
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