Custom Muzzle Brakes

Original article photographySource page 13

Recently, while completing a custom rifle build (which you may have seen in recent pages of this very magazine), I made the decision to install a muzzle brake on the rifle. Some of you more observant readers may have noticed that I had photos of a brake I previously made in my recent article, but it ended up being a massive boat anchor. It was too heavy and I felt it could be a detriment to accuracy if I used it.

After weeks of perusing the Web and poring over the plethora of options, I could not find one that had all the features I wanted nor the desired finish. Mine being a stainless steel barrel, and all the options I found that had what I wanted were either out of stock or blued in finish, I decided I’d have to design and make exactly what I wanted. I’d finally narrowed my drawings down to two similar designs.

My first steps were to take the design I had, shrink it down to be more streamlined and weigh considerably less, but still possess all the features that I wanted on the part and not look clownishly large when installed. The muzzle diameter on my blaster is one inch, so I knew what that one diameter would be.

After a few different attempts with the drafting software and a hard drive loaded with rejected designs, I determined that the body would need to be 1-1/4" in diameter to get the desired pocket size and still be small enough to look like it belongs in its place. Due to these parts being made of stainless steel to match the barrel, which is a very dense material, I machined away metal in every possible area to cut down the weight.

I had also milled 1/8" off of the top and bottom of the parts to thin them out to one inch to match the smaller diameter and muzzle size. As some of my fellow longrange enthusiasts know, the 6.5mm family of cartridges already are rather tame in terms Far

Original article photographySource page 14

of recoil. So the two brakes I’ve come up with feature large pockets up top to direct gases upwards to tame felt recoil even further, as well as one having an array of 3/16" holes and the other having 3/16" wide slots on either side to further disperse gases. Both brakes feature 3/8" diameter round-bottom pockets leading into the port and starboard features. Both options feature a 9/32" bore to eliminate any chance of "baffle-strike" by the bullet and 5/8-24 threads to attach them to my muzzle.

I also undercut the bottom of the threaded hole to help the brake bottom out and assist with getting those threads all the way to the bottom of the hole. The tap I have includes a leading taper that covers the first two threads, so the undercut allows the tap to cut full diameter threads all the way down the hole. I also engraved a version of Marvel’s Punisher character logo on each one, with one having the older version of the logo and the other having a more recent version.

The brake that I put the older version on, I also added some custom lettering with my last name below the emblem. This lettering, with the custom leather sling with my name on it, will set my rifle apart in more ways than most. After all the machining was done, I bead blasted all the surfaces, including the insides of the pockets on the top and sides until all of the machining marks disappeared or smoothed out.

With some sheets of 320- and 400-grit sand paper and some light cutting oil, I hand-lapped all the flat surfaces to a polished shine before finishing the entire outside with a pass of Scotch-Brite scrubbing pads to round off any last adjoining edges. This, I feel, gives these parts a gorgeous contrast of the polished flats and the matte finish of the rounded facets and pockets.

To assist with installation I went back to Brownells to order one of their Muzzle Shim Kits for .30 caliber and 5/8" diameter muzzles along with an AR-10 crush washer also for 5/8" threads.

Not knowing exactly where the threads start radially in the parts I made, I didn’t know exactly how they would "clock" or "time" on my rifle, so I ordered both in case it was just a short distance to cover (thus necessitating the shims) or if it would Far Far The model with the array of three holes (left) and the model with the fulllength slot (right). Notice the top flat surface has been hand-lapped and polished after the entirety was bead-blasted.

Original article photographySource page 15

You may also notice the lapped and polished flat surfaces, too. be a considerable distance (thus needing the AR-10 crush washer). Now, to choose which one I’d rather have installed. Decisions, decisions… Thank you all, as always, for reading. I hope this outline can, in some way, help other gunsmiths or hobbyists to bring a design of their own to fruition.

I know that some of us gun enthusiasts often find that we need something for a gun, but I put the older version of the emblem on the arrayed-hole model (left), along with the custom lettering below it to really set this rifle apart from all others. The slotted model (right) bears a more recent version of the emblem. I would like to thank the Marvel Cinematic Universe for creating these stunning symbols. can not find exactly what we want a majority of the time.

Short of contracting a machine shop to make a custom part, this should give you the basis for how to do it yourself. I’d like to send a special thanks to Brownells for having the needed parts and tools, Marvel and their Cinematic Universe series of movies for the two emblem designs, and Auto Desk for the use of their drafting and design software. AG American Gunsmith Reader Services 1.