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Posted: 6/5/2026 9:44:53 AM EDT
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Hi all, new here. First AR, first build. I got a BKF 16" 5.56 complete upper that came with a muzzle brake - for NJ compliance. It has a Ballistic Advantage Govt profile barrel and the BKF M4 MK1 5.56/223 Comp. Loud I know, but legal. I went with their BCG so they test it together. Not assembled or fired beyond the factory test fire. (I did not realize they offer a $30. pin and weld service until after I got the upper.) I have DIY skills and tools to pin and tig weld it. I would consider paying the $40 -$50 locally but I am leery and short on trust on anyone I can't vouch for working on anything unless I absolutely cant do it myself. All the searches I have seen have you drill through the brake before installing it, then drill through the hole to the root of the threads, or .03 - .05", etc. into the barrel. I don't see a good way to gauge the depth of the hole with the brake already installed. Is there? Or, should I remove it and proceed as normal. If so: Should I use an upper vice block, or pull the handguard and groove out some 2x4 to vice the barrel? Can I reuse the shim or crush washer? Thanks ahead, John |
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remove muzzle device or leave on, whichever allows you drill a deep enough pocket. drop a pin in that prevents movement and weld over. Secure by upper vise block or barrel, whichever you have. No need to remove the rail unless it interferes with access to the muzzle Shims can be reused, crush washer would need to be replaced with new. |
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I'm pretty sure but not 100% sure. I know the 16" typically meets the min length requirement. With a rifle / carbine stock, i know it cant have a flash hider. I will pin the collapsible stock. I believe I can only have 1 "evil" or restricted feature in addition to a detachable magazine. The 3 evils I have are: 1. Detachable mag 2. Pistol grip 3. Threaded muzzle So, I believe pin and weld is required.. |
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Originally Posted By jtcnj: I'm pretty sure but not 100% sure. I know the 16" typically meets the min length requirement. With a rifle / carbine stock, i know it cant have a flash hider. I will pin the collapsible stock. I believe I can only have 1 "evil" or restricted feature in addition to a detachable magazine. The 3 evils I have are: 1. Detachable mag 2. Pistol grip 3. Threaded muzzle So, I believe pin and weld is required.. ahhh interesting |
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Originally Posted By jtcnj: That is the question - how to judge the depth of the hole with the brake already installed. A moderate dimple for the pin to seat in to prevent rotation is all that you need. I "eyeball " any that I do personally. Go slow, check frequently. Without specialized equipment you'll have a hard time gaging actual depth while drilling. EDIT: Typically, crush washers are a one time use component, not to be reused. In your case, it will be fine to reuse if only for brake timing purposes. Once pinned and welded correctly there is no chance of your muzzle device loosening . |
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Originally Posted By TGWLDR: A moderate dimple for the pin to seat in to prevent rotation is all that you need. I "eyeball " any that I do personally. Go slow, check frequently. Without specialized equipment you'll have a hard time gaging actual depth while drilling. EDIT: Typically, crush washers are a one time use component, not to be reused. In your case, it will be fine to reuse if only for brake timing purposes. Once pinned and welded correctly there is no chance of your muzzle device loosening . I could eyeball it if I was familiar with the dimensions of the brake, or the height of the thread / thread root vs the barrel shoulder / where the crush washer sits against the barrel. Proceeding slowly and checking often, what do I check for, (besides if I drilled into the bore)? I will use tape on the bit as a rough depth gauge. Can you see in the drill hole when you reach the threads? I will likely remove it, and maybe reuse the washer. I don't trust the Amazon crush washers, but don't really want to pay $6. - $13 to ship a $3 or $5 washer from AR15discounts, Primary Arms or wherever. I do want to do it right though. |
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Originally Posted By jtcnj: I could eyeball it if I was familiar with the dimensions of the brake, or the height of the thread / thread root vs the barrel shoulder / where the crush washer sits against the barrel. Proceeding slowly and checking often, what do I check for, (besides if I drilled into the bore)? I will use tape on the bit as a rough depth gauge. Can you see in the drill hole when you reach the threads? I will likely remove it, and maybe reuse the washer. I don't trust the Amazon crush washers, but don't really want to pay $6. - $13 to ship a $3 or $5 washer from AR15discounts, Primary Arms or wherever. I do want to do it right though. A set of dial calipers would help your cause tremendously. Do not expect to judge depth by simply trying to sight into a ~3/32" blind hole. |
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Originally Posted By nvcdl: Use hi-temp silver solder - no drilling needed Another excellent option for those DIY guys without a desire to invest in specialty tools. Old /dated thread link HERE |
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Use a center cutting mill. It will cut a flat bottomed hole to the root of the threads. You won't have to go as deeply into the barrel. Mill down to thread depth plus a tiny bit further. Cut part of the shank off an old drill bit so it mates with the flat bottom. TIG it. Done. |
"Major, with the weapon shops out of the way we can introduce steadying laws that could not be flouted." -A.E. Van Vogt 1951
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Originally Posted By MaxSpeed74: Use a center cutting mill. It will cut a flat bottomed hole to the root of the threads. You won't have to go as deeply into the barrel. Mill down to thread depth plus a tiny bit further. Cut part of the shank off an old drill bit so it mates with the flat bottom. TIG it. Done. Excellent plan but a bit specialized for the average DIY guys without access to equipment and/or lacking the skills. |
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Sounds like you have the desire and know-how to do this yourself, it's not too difficult. Just make sure you have the right tools. If you don't have all the tools, you may spend more on the tools than on just sending it off though. There are a few very reputable gunsmiths on here that could do it for you as well. I'd recommend Steve from ADCO in Ohio. The smart-ass answer would be to wrap a whole bunch of teflon tape on the threads, then spray paint it black to match the barrel. Now it looks like a crowned barrel! Welcome to the forum. |
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Originally Posted By Gr0g: Whichever route you take, get a brake with a <3/4" OD. These are nice. |
"Major, with the weapon shops out of the way we can introduce steadying laws that could not be flouted." -A.E. Van Vogt 1951
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