Flash-hole size variation!

[M14AMU]

From time to time with a particular lot of brass that I have when shooting from 1000 yards I've gotten a few shots that I couldn't account for when shooting a very accurate rifle in 30/06 caliber. Even those individuals with much experience from time to time experience 'brain farts' and it's quite apparent that I let some cases get by me that I have not uniformed the primer/flash-holes such that all are the same size. I'd lay $$$$ on the bet that this is my 'unexplained flyer' problem! These will be corrected shortly! The two cases at the top are the same but the lower case has a highly obvious smaller flash-hole!


Flash-hole variation in size! by Sharps45 2 7/8, on Flickr

What sometimes seems insignificant......AIN'T!!

 

[357Mag]

RM -

Howdy !

IMHO - when it comes to the brass, do what you can to make all of them the same.

You can use drill bits form the hardware store, as flash hole " go / no - go " gages.
For me, culling those brass that are non-spec, has helped keep groups small.

Uniform the primer pockets for the same depth on all. On both my .35 Rem and .22-35 wildcat; uniforming the primer pockets made a noteable difference.

Outside neck turn, even if only for a skim-trim to remove " orange peel " surface of the brass.
Neck turning is one of a couple contributing reasons, for the existence of bushing-type NS dies.

I've had Lapua brass that has shown the need for some of the above procedures, so that brand may not be exempt ... in my view ( mine were 6BR ).

With regards,
357Mag

 

[gpoldblue]

RMulhern.......Think about what other variances might be lurking in those cases! Also,might be the angle of the camera,but it looks like the flash holes are off-center. I think I'd change brands of brass from Winchester to the more consistant Lapua. I've seen pics of your groups on other posts and they're outstanding...says alot about the rifle/ammo combination AND the shooter. Keep up the good work.

 

[M14AMU]

RMulhern.......Think about what other variances might be lurking in those cases! Also,might be the angle of the camera,but it looks like the flash holes are off-center. I think I'd change brands of brass from Winchester to the more consistant Lapua. I've seen pics of your groups on other posts and they're outstanding...says alot about the rifle/ammo combination AND the shooter. Keep up the good work.

Yes sir...it was the camera angle! They're on center! And now...they're all the SAME size!! ;D I just over-looked these cases recently when I loaded them and didn't catch that some were smaller/larger! :-[

 

[Enosiophobia]

Necro thread resurrection. I happened to be cleaning a bunch of flash holes and thought I was seeing things. Verified with a 1/16" drill bit. They are of a different size.

Thinking of eliminating variables, anyone object to drilling out the smaller holes to match the larger ones? The larger holes do dominate the group. The group on the left are the larger variety. I'd rather not toss good brass.

 

[DocDoc]

Almost looks like the large hole was caused by punching out a primer with the wrong size punch found in large primer sets.

 

[M14AMU]

Upon several 'second thoughts'.....sometimes we're just looking for an excuse for poor marksmanship which is the real issue!!

 

[BORGY76]

What if a guy made a jig with a bushing to fit primer pocket and an endmill to bore out flash holes to a consistent size?

 

[ronemus]

Sinclair sells a device, and I've used it on all my brass. Their replacement reamers are rather pricey, so I buy them on Amazon and shorten the shank myself.

 

[Enosiophobia]

Upon several 'second thoughts'.....sometimes we're just looking for an excuse for poor marksmanship which is the real issue!!

Not sure I understand the meaning of your response.

 

[rjtfroggy]

Necro thread resurrection. I happened to be cleaning a bunch of flash holes and thought I was seeing things. Verified with a 1/16" drill bit. They are of a different size.

Thinking of eliminating variables, anyone object to drilling out the smaller holes to match the larger ones? The larger holes do dominate the group. The group on the left are the larger variety. I'd rather not toss good brass.

View attachment 1349032View attachment 1349033

I take a .071 drill to all my Lapua brass. It is the first step in prepping for me.

 

[rwj]

I take a .071 drill to all my Lapua brass. It is the first step in prepping for me.

Why?

 

[rjtfroggy]

I use cci 400's and I feel I get better ignition. Plus, I was told back when I started shooting BR that a larger flash hole gave a better flame pattern. Can I prove it, no, does it work for me, yes.
I have yet to have a single fail to fire or misfire. Probably just jinxed myself.

 

[Bill K]

Trigger control will have more of effect than the size of the flash hole.