A friend gave me a 44/40 non fluted cylinder that works perfect in my 10 1/2 in new model super Blackhawk, timing and lockup perfect. The diameter of exit of the chamber measures .422 in all six chambers while my 44 mag cylinder all measure .429. I remember reading on the forum what to do but cannot seem to find how to correct this on the 44/40 cylinder, maybe someone could recommend how to do this or a gunsmith that they would trust to do it. I am planning on reloading for 44/40 as I am already reloading for 44 magnum. Any help or recommendation would really be appreciated. Thanks in advance for your help.