muzzle brake mounting - shim, nut, or washer?

[Teh_Sp00ky]

I'm interested in buying the m4-72 in .308, 5/8-24 and I'm having issues figuring out shims, nuts, or washers.

The m4-72 product page says specifically not to use crush washers. (really, why?)

They suggest the accu-washer which is $25. Seems expensive for what it is. Brownells has a shim kit for $5 but it doesn't specifically mention "precision" (shouldn't matter eh?) . Peel washers were also suggested. Then locking nuts... they would work I think but they look like garbage imo.

I'm leaning towards the brownells shim kit.

 

[Onyx Z]

Shims and Rocksett.

 

[VegasHKShooter]

The reason they don’t recommend crush washers is the potential for a lack of concentricity. Crush washers are ok on an A2 flash hider on a generic mil spec barrel. Going past that, you really should be using shims that will control to the .001 or so where you hit your desired torque. Many interesting things can happen to precision barrels when you start over torquing things at or near the muzzle.

 

[character0]

I'm interested in buying the m4-72 in .308, 5/8-24 and I'm having issues figuring out shims, nuts, or washers.

The m4-72 product page says specifically not to use crush washers. (really, why?)

They suggest the accu-washer which is $25. Seems expensive for what it is. Brownells has a shim kit for $5 but it doesn't specifically mention "precision" (shouldn't matter eh?) . Peel washers were also suggested. Then locking nuts... they would work I think but they look like garbage imo.

I'm leaning towards the brownells shim kit.

I used a flat surface with some 400grit sandpaper and just did figure eights on the mating surface of my muzzle brake. Only needed a couple thousandths to time it. Still mounts a supressor true and times up properly when torqued. Not an operation for the feint of heart I suppose, but it works for me. Otherwise grab the peel washers.

 

[longshot2000]

I used a flat surface with some 400grit sandpaper and just did figure eights on the mating surface of my muzzle brake.

Have not heard of that method, but why not.