Flash hole

bearhunter338-06

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Do you clean the flash hole in your brass?

Can you use a small drill to give the flash hole a more uniformed hole? Would it be wise to make the flash hole slightly bigger?
 
Brass cases, other than Lapua and Norma, have punched flash holes. On the inside there is some flash metal around the hole. If you want to do some case prep for accuracy, remove this flash.

here is how I do it. I clamp my electric drill in a vice and set it to medium speed. With a 1/10" drill bit, or a bit bigger, I touch each flash hole (from the inside). It chatters as it removes the flash, then runs smooth as it champfers the solid web.

Do not drill the holes larger. Tests have proven that the smaller the flash hole, the better the SD.
 
Or you could just spend $20 ;)

FlashHole%20Uniformer%20Lg.jpg
 
Yes. Once I checked several brands and tried a flash hole reamer and saw what came out, hell yah, always. Once they are done, all is good !
 
Or you could just spend $20 ;)

FlashHole%20Uniformer%20Lg.jpg

I've got one of those and used it for a while but I couldn't tell any difference in accuracy, maybe a benchrest shooter would notice an improvement. On the other hand, you will only have to do it once and if you neck size only your case life will be pretty good, so not a huge investment of time.
 
SS media does it all

SS media doesn't uniform flash holes, it only cleans primer pockets.

To fix up the flash hole, you need to remove the extra bits of metal on the inside that result from the procedure used to create it.

EDIT: Meant to say it only cleans primer pockets. Obviously, SS pins can uniform neither primer pockets nor flash holes.
 
Last edited:
bearhunter .338-06;
Good morning to you sir, I trust the day is as nice in your part of BC as it is down south here.

A very similar tool to the Lyman shown in above posts resides in my shelf of "goodies that seemed like I needed them at the time". It's sitting right beside a tool that cuts the back side of the primer pocket to the correct depth and squares it up.

At one point in my past I got a wee tad too competitive in the hunter rifle class shoots we were putting on in the local club and began to test everything I could regarding hand loads to get that "edge".

I was competing with a 788 carbine in .308 and a BBR in .30-06 at first, though fairly quickly I went with the 788/.308 combination exclusively because it was far less fussy overall.

Anyway once I had the details wrinkled out on that little rifle, several other shooters as well as me were able to put our shots within ÂĽ" of point of aim at 100yds - and for those who've not shot a fair bit I'll say that in the real world that's pretty rarefied air or so has been my experience anyway.

The short story is that the case prep tools did not make any difference at all - IF - one started with half decent brass. Honestly I ended up using a bunch of white box Winchester once fired stuff that I salvaged from the pail at the range - it was loaded in Canada somewhere way back in the day....

If I'd have had access to something as wonderfully made as the Lapua cases I recently picked up for a 6.5 Swede project - or the Hornady brass for the same project for that matter - I'm quite confident that I'd have been much farther ahead. Other posters have mentioned that some European brass appears to be drilled and not punched. I'll add older RWS brass to the list of very desirable brass to work with if one can find it. In my limited experience Lapua brass appears to be nicer than Norma - but whether most rifles/shooters would ever tell the difference remains open to conjecture and debate...

Anyway sir, that's where I'm at today with my case prep, but sometimes it doesn't hurt to experiment a bit yourself either as there's no substitute for really and truly "knowing" something to be true - if that makes any sense?

So for sure sort your cases for weight and even brand if you're getting "serious" about accuracy - but in my experience how straight the bullet is installed into that case will have a much greater effect on the resulting cartridges accuracy capability.

Again I hope that made some sense to you sir and was somewhat helpful. Good luck on your reloads whichever way you decide and if you think I can be of any assistance then by all means give me a shout.

Dwayne
 
Very much doubt SS media will 'uniform' anything, never mind a flash hole. Isn't really necessary anyway.
Suspect you'll find Lapua and Norma punch 'em too. Drilling costs time and money with no return.
 
One word of caution here. DO NOT enlarge flash holes beyond specs. [Maximum diameter .085"]
There is evidence to support pressure increases when flash holes are enlarged to above that threshold.

European brass, in my experience, usually has slightly smaller flash holes than does N.A. produced brass.

In any event, diameter is established by SAAMI at .078" to .082" in large rifle cases; at .074 to .078 in small rifle.
European CIP specs are 1.6-1.7mm. [.63" - .67" ]

My Lapua brass in several chamberings measures consistently .078"

Regards, Dave.
 
Lapua and Norma do have more consistent flashholes than other brass mfgr.

My guess is that you have to get beyond say 400 yd before uniforming the flashholes
starts to pay off. Uniform brass weight would probably be more important.

I find that Lapua brass has the least weight variance *and* has nice flashholes too.
I use it for long-range shooting (i.e. beyond 400 yards).
 
I figure you only have to do it once and it won't hurt accuracy and might even help so I debur my rifle brass flash holes before I reload it for the first time. If you use a flash hole uniformer with an adjustable stop and your brass is all trimmed to the same length it is quick and easy, I use a cordless drill to turn the uniformer.
 
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