Prepping Flash Holes
- Thread starter Gerald
- Start date
Just buy the Lyman tool, purposely made for the job and it will save you a lot of trouble.
The flash hole uniforming tool is usually used "inside" the case, through the case mouth.
It does three jobs at once.
There is a locking collar on the drill stem to adjust depth, which helps to keep things uniform
There is a larger portion of the tool that gets rid of the burrs that often are inside, around the flash hole.
The small pilot drill on the front will be just large enough to drill out the flash holes to uniform size.
Your local gunshop likely has several of these in stock.
The flash hole uniforming tool is usually used "inside" the case, through the case mouth.
It does three jobs at once.
There is a locking collar on the drill stem to adjust depth, which helps to keep things uniform
There is a larger portion of the tool that gets rid of the burrs that often are inside, around the flash hole.
The small pilot drill on the front will be just large enough to drill out the flash holes to uniform size.
Your local gunshop likely has several of these in stock.
littlehughey
Regular
- Location
- Central Alberta
The K&M tool is fantastic, wish I'd not even bothered with the lyman
Munkey1973
CGN frequent flyer
- Location
- Regina, SK
I wouldn't recommend any drill [bit] to uniform flash holes.
You'd be well advised to get a specific tool.
I hear the K&Ms are nice.... I have both the 22 and 30 caliber tools made by 21st Century Shooting.
Like the K&Ms, the 21st Centurys will index of floor of the case.... which means you can a more consistent deburr especially when apply ample pressure on the tools.
But I am not 100% sure (could be wrong) if the K&M have a hexagon head like the 21st Century which will allow you to use a power screwdriver or drill.
You'd be well advised to get a specific tool.
I hear the K&Ms are nice.... I have both the 22 and 30 caliber tools made by 21st Century Shooting.
Like the K&Ms, the 21st Centurys will index of floor of the case.... which means you can a more consistent deburr especially when apply ample pressure on the tools.
But I am not 100% sure (could be wrong) if the K&M have a hexagon head like the 21st Century which will allow you to use a power screwdriver or drill.
I know where you're coming from but the Lyman bit can easily be taken out of the handle and chucked up into a cordless drill or even a drill press
It also comes in handy for cleaning crud out freshly cleaned up cases, using the bit in its original wooden handle.
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As most of you now know, I used to work in a ballistics R&D lab, and being a curious guy I tested a lot of my ideas and also had access to a lot of test results from other labs.
I ran a personal test (20 shots per flavour) of primer pocket conditioning and saw a very significant improvement by kissing the inside of the flash hole with a reamer, to take off the flash inside the case, made when the hole was punched. (Note: Not needed with Norma and Lapua brass). Other primer pocket conditioning either produced no benefit, or made things worse.
I have used a purpose made tool to do this and have also just used a 1/8" drill bit in an electric drill. If I have a bucket of brass to process, I lock the drill in a vice and that way I have two hands free to kiss the drill bit. As you touch the tool to the hole, you feel a bit of chatter as it hits the rough flash. As soon as it feels smooth, stop. Inside you should see a hole with a little champfer around it.
As for the flash hole, the bigger the hole the bigger the SD. So don't make the hole any bigger. SD is inversely proportional to hole size. That may be counter-intuitive - but don't argue with it. You may find some match brass has a smaller than usual flash hole that needs a small decapper pin. there is a reason for that small hole.
I ran a personal test (20 shots per flavour) of primer pocket conditioning and saw a very significant improvement by kissing the inside of the flash hole with a reamer, to take off the flash inside the case, made when the hole was punched. (Note: Not needed with Norma and Lapua brass). Other primer pocket conditioning either produced no benefit, or made things worse.
I have used a purpose made tool to do this and have also just used a 1/8" drill bit in an electric drill. If I have a bucket of brass to process, I lock the drill in a vice and that way I have two hands free to kiss the drill bit. As you touch the tool to the hole, you feel a bit of chatter as it hits the rough flash. As soon as it feels smooth, stop. Inside you should see a hole with a little champfer around it.
As for the flash hole, the bigger the hole the bigger the SD. So don't make the hole any bigger. SD is inversely proportional to hole size. That may be counter-intuitive - but don't argue with it. You may find some match brass has a smaller than usual flash hole that needs a small decapper pin. there is a reason for that small hole.
