Uniforming the flash hole, Necessary?

[moosehunt]

My experience is that regarding brass with punched flash holes (not Lapua or Norma), you may get an improvement with the first firing by deburring the flash hole, but generally after the first firing, no advantage. I have observed that if there is a burr on the flash hole, it almost always trims itself with the first firing, the second for sure. No doubt, there could be exceptions. All in and all done, I debur the flash hole on new brass. It is a one time deal. Probably overkill, because new brass is never used for important loads by me anyway. I want it fired once, then I neck size for anything of significance, i.e. hunting.

 

[Lance Boyle]

Not for nothing, the brass from FGMM shot pretty good the first time didn't it?

Like others have said, it doesn't take much to just go ahead and do it. I do it on some heavy barrel rifle ammo but I don't bother on garand and M14 ammo anymore.