Has anyone experience with this Procedure? FlashHole Uniforming? Can you Explain The Benifits and Does any one have proof?
Mick
PHX AZ
Mick
PHX AZ
K&M Flash Hole Uniformer, for 308 & 6BR.
- Thread starter mickwwalker
- Start date
Thanks for your reply very helpfull.
mickwwalker said:
Proof ? You bet ! Regardless of caliber you may not want to uniform the flash hole the first time, or ever again after watching Jack Neary's video. I don't do it anymore with my 6PPC or 30BR. I now just uniform the primer pocket and deburr the flash hole opening [not the tunnel] on the inside of the case
Jack Neary has great experience. He was inducted into the Benchrest Hall of Fame last year and just returned from the World Benchrest Championship, held in France, as a member of the winning team.
His video will cover it all, and then some. Pull up a comfortable chair, maybe a cold one too, then sit back and listen to an expert.
http://www.youtube.com/view_play_list?p=7D85822FD9E41FF2
Hit ... Play All ... and each one transitions into the next one automatically with a moderate pause between Parts. This is much more than Tuning. Case prep is covered in DETAIL.
I recently bought a ".062 K&M Flash Hole Tool". Stupid me took for granted that meant it'd do the flash hole to .062" not the .0688" that's in the old 6mmBR Cartridge Guide. But out of curiosity after doing most of my just blown out new cases, I tried to redo them with my Sinclair tool. Surprise, surprise, the holes were a good deal larger than the Sinclair. So I mic the K&M and find it measures .0655" across not .062". I think the holes it cuts are closer to the .068" that you'll find stated for the K&M in the 6mmBR Cartridge Guide. So....
If you're looking, like I was, for a small flash hole stay away from the K&M or at least be sure to mic the one you get first. The idea behind it, with the tapered cutter and sleeve to keep it uniform and from going in to deep are great. But for some reason they ground mine too large. Me, I've got 88 just blown out 30Dasher cases with a flash hole bigger than I wanted. That'll keep me wondering for the life of the cases.
If you're looking, like I was, for a small flash hole stay away from the K&M or at least be sure to mic the one you get first. The idea behind it, with the tapered cutter and sleeve to keep it uniform and from going in to deep are great. But for some reason they ground mine too large. Me, I've got 88 just blown out 30Dasher cases with a flash hole bigger than I wanted. That'll keep me wondering for the life of the cases.
On my 6BR I did one batch with the K&M tool causing the enlarged flash holes and left one batch untouched.
I was also concerned that I ruined the brass by enlarging the holes in the first group but turns out after doing extensive ladder tests that both sets of brass will consistently group under 1/2" at 300 yards and looks like it is one of those non-issues and I probably won't try to better the Lapua brass in subsequent lots except to remove any obvious flashhole burrs.
I was also concerned that I ruined the brass by enlarging the holes in the first group but turns out after doing extensive ladder tests that both sets of brass will consistently group under 1/2" at 300 yards and looks like it is one of those non-issues and I probably won't try to better the Lapua brass in subsequent lots except to remove any obvious flashhole burrs.
I use Win brass because I leave 75% in the grass at a match, the flashholes are ugly, the primer pockets are all over the place, I uniform every pocket, and I deburr the flashholes with a Sinclair Gen 2 tool, and yes it does make a noticeable difference, the K&M Sinclair and Possum Hollow tools all have there cutting depth stops in the same place, they cut until the stop reaches the web of the case, and trim length is not important.
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