Primer flash hole diameter

[X-ring]

The Black Powder Cartridge News summer issue had an article by Rick Moritz that investigated if enlarging cartridge case flash hole diameter increased accuracy. 35 shots for each diameter [5/64 factory diameter, 3/32, and 1/16 inch]. Also included was a test using factory cases with a paper wad inside the case to keep powder from contacting the primer. His tests indicated that there was no statistical benefit in shrinking group size between the standard factory flash hole size and the enlarged flash hole diameters. He did notice that the tests using the paper wad in the factory case increased group size by causing vertical stringing. I might add that my tests of uniforming primer pocket depth were also a waste of time. I'd much rather be practicing than worrying about case minutae. X

 

[anonymouscowherd]

Primer pocket uniforming (other than when needing to remove crimps from mil brass) and flash hole uniformity/size are things the ultra serious bench rest folk do when they've done everything else, trying to shave off that last 0.01" from their groups....

And while the techniques could work with BP cartridges... I don't think BP itself has enough consistency to actually get any benefit from the extreme consistency chase...