Flash hole uniforming

[Vanilla Gorilla]

Have any of you used a drill bit to uniform your flash holes?
What size drill bit do you use?

[toby]

You are only trying to clean it out really, if you do this, just use one that just fits snug, if you go small it can get out of shape real fast un uniformed. If you go to big then you drill more material then needed. I don't know that this would have much effect on performance? I know a guy who swore by drilling them out larger but what it did ???????

[Vanilla Gorilla]

You are only trying to clean it out really, if you do this, just use one that just fits snug, if you go small it can get out of shape real fast un uniformed. If you go to big then you drill more material then needed. I don't know that this would have much effect on performance? I know a guy who swore by drilling them out larger but what it did ???????

From what I understand is uniform flash hole = uniform flash uniform flash = uniform powder burn and uniform powder burn = tighter groups don't know how big of a difference uniforming the flash hole really makes but I want to try to shrink my groups as much as I can right now

[ireload]

The tool also cuts a bevel on the inside part of the hole which also removes any burrs that are left behind from the manufacturing process. It also makes the hole more round.

I would not use a standard drill bit. It's cheap enough to purchase an actual flash hole uniformer. But be careful when using one that's leght adjustable. You can remove to much brass material on the bevel. The tool works great as long as you have "uniform brass leght" if not then you can have un-even bevels cut inside the brass.

I cut enough when I see a small bright ring inside the brass then I'm good. I would think that it give a more uniform ignition since any flash hole burr would be gone.

The only thing I cannot tell you is how much of a "accuracy" you are going to gain since there's other factors involved. But I would load something like 10 rounds with non-uniformed flash holes and 10 rounds with uniformed flash holes then do you side by side testing. I would pick what ever load combo that you have come up that gives you a the most accuracy to try the 10/10 testing.

[J-cat]

I suggest you wet tumble your brass in stainless media to get all the carbon out of the case. Then neck size with a Lee collet neck die. This will ensure uniform tension on the bullet without any contaminants getting inbetween. Your ES will come down and that will impact your LR accuracy more than all the uniforming tricks combined.

[AMProducts]

There are specialized tools for this. The main concern when it comes to having a uniform flash-hole is that it's concentric to the case. Just using a drill bit without a pilot will only exacerbate the issue. Shooting a 10rd group at 300 yards with all the bullets slicing the X-ring is good enough for me, and I've been able to do it without flash hole uniforming. The biggest accuracy issue most people seem to experience relates to crimp and variance in neck tension. Neck turning, and neck sizing with a collet, or a sizing bushing (like the RCBS, CH4D, Redding dies) gives you the best return on investment in terms of "specialty" case prep tools.

[wtkaiser]

The consensus among modern-day gun writers is also mixed on this, but I believe most say something like 'do it if it makes you happy, but there's no real need until you can measure your groups in small decimals'. I clean my primer pockets because Elmer said to, and my groups are measured in 'minute of dinosaur'. I have no intention of taking the time to buy and use such specialist equipment.

[Fjold]

I bought a flash hole uniforming tool for like $10 twenty years ago. I can't remember what brand it is but I was amazed at how much different the amount of material it removed from different case. Regular brass has no consistency.

Of course, you could just but Lapua brass and not worry about it.

[Fjold]

I bought a flash hole uniforming tool for like $10 twenty years ago. I can't remember what brand it is but I was amazed at how much different the amount of material it removed from different case. Regular brass has no consistency.

Of course, you could just but Lapua brass and not worry about it.

[Fjold]

I bought a flash hole uniforming tool for like $10 twenty years ago. I can't remember what brand it is but I was amazed at how much different the amount of material it removed from different cases. Regular brass has no consistency.

Of course, you could just but Lapua brass and not worry about it.

[kmullins]

Fjold is right - Lapua brass has the flash hole drilled not punched which eliminates the flash hole bur.

In my opinion, with bulk brass (Remington, Winchester, LC, etc.) sorting by case weight and neck thickness are the most important...