muzzle break reaming

Discussion in 'Gunsmithing' started by rscott5028, Aug 29, 2011.

  1. rscott5028

    rscott5028 Well-Known Member

    Apr 18, 2010
    For the 2x brakes that I've installed, I dialed in the first few inches of the bore to +/- .0001" with a Grizzly Rod and reamed .020" over bullet diameter. They seemed to work fine. But, I'm wondering if I can do better.

    I see other posts indicating that less than .020" doesn't make much difference and more than .040" reduces effectiveness.

    I've also seen where some have tried progressively decreasing from .040", .030", and .020" in an attempt to help distribute the gases from first thru 3rd baffle. If you've tried this, is it worth the effort?

    Also, do you ream or do you simply bore yours?

  2. J E Custom

    J E Custom Well-Known Member

    Jul 29, 2004
    I personally like to use a boring bar to size the break. I already have the barrel set up true
    in the lathe for cutting the threads and it guarantees that the hole in the break is in perfict
    alignment with the bore and also gives me the flexibility to customize the diameter.

    Also I have seen poor installations where the bullet was striking the break and accuracy
    was out the window. most of these were hand taped or threaded and only a few were
    misalignment of the threads on the breaks and this was minimal.

    I have experimented with enlarging the ports as they go out and found no measurable
    difference in recoil reduction.( also the bore diameter ).

    Reaming is probably the most common way but you have to have a lot of reamers to
    do all of the sizes.

    That being said: I have tried boring the break very close to see the effects(.004 larger
    than the bore) and had no bullet strikes but saw no improvement in recoil reduction but
    did see some accuracy loss until the bore was .015 larger.

    After that the bore size did not effect accuracy but loss of recoil reduction did occur after

    So in my mind, this confirms that the bore should be close to .020 thousandths.


  3. rscott5028

    rscott5028 Well-Known Member

    Apr 18, 2010
    JE - Thanks!