so I bought a Lyman flash hole deburrso tool and it says to set it up to remove .010 set if up and tried 3 cases seems like it is removing quite a bit of material and I still have burrs when I look thru the flash hole and ideas on how much to remove befor it becomes unsafe on federal gmm cases
Flash hole uniforming and deburr
- Thread starter Wjesswheel
- Start date
I have RCBS flash hole de-burring tools, I do not use them because I have not found flash holes with burrs. I thought about beveling the edge of the hole but if I did that I would turn the tool without a load against it to remove the burs I created. I also have a flash hold gage, I have used it when checking for cases that got hammered with heavy loads, again I have never found a burr in a flash hole with the flash hole gage.
F. Guffey
F. Guffey
Never seen a burr in a flash hole. Scary hogging out a lot of metal. If the flash hole is punched or drilled from the head end when the primer pocket is created, the burr should be in the inside of the case. My flash hole uniformer has two cutting diameters. The handle is 2 3/4" long so I assume it's supposed to be inserted from the neck end. Don't have the original instructions from 1975. I have used it to uniform the flash hole only by hand with a few twist from the head end without wanting the larger diameter cutter to touch the pocket. I use a RCBS pocket uniformer to get a flat primer pocket bottom. It has a fixed depth stop. I see no reason to have an adjustment for cutting depth. They should all end up being within 1 or 2 thou of the same depth. If you hold a case up to a light you should be able to see the tiniest burr in the hole. If the flash hole is uniformed there cannot be a burr in the hole. If a bur exist adjacent to the hole inside the case I don't care. Removing 10 thou., sounds like they are trying to remove or flatten a small hump created by punching in the primer pocket? I use Lapua cases only the primer pocket uniforming tool doesn't reach the bottom of the pocket on about 1 out of 10 cases. Different amount cut from most cases (uniforming).
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Sinclair tool works great and easy to use.
I got the Lyman tool and use it on Winchester brass...
It's important that all cases are the same length, withing a few thou.
I do the first case until the burrs are all gone. I take out the tool out of the flashole, and with it's tip feel for burrs inside the case, if any still remain I ream a lil more till they're all gone.
Once I'm satisfied all burrs are gone, I tighten the set screw, unscrew the tool from the handle and chuck it in a cordless and do the rest of the cases. Also check for burrs every few cases to make sure.
It's important that all cases are the same length, withing a few thou.
I do the first case until the burrs are all gone. I take out the tool out of the flashole, and with it's tip feel for burrs inside the case, if any still remain I ream a lil more till they're all gone.
Once I'm satisfied all burrs are gone, I tighten the set screw, unscrew the tool from the handle and chuck it in a cordless and do the rest of the cases. Also check for burrs every few cases to make sure.
This is what you want. Indexes off the case floor.
http://www.xxicsi.com/flash-hole-debur-tool.html
http://kmshooting.com/flash-hole-uniformers/std-0-080-pro-flash-hole-uniformer.html
http://www.xxicsi.com/flash-hole-debur-tool.html
http://kmshooting.com/flash-hole-uniformers/std-0-080-pro-flash-hole-uniformer.html
R.Morehouse
Gold $$ Contributor
Saw a multi part youtube vid with Jack Neary and he was asked about flash hole reaming. He shared that they took T.Boyers rail gun in a tunnel and did a bunch of testing with Lapua brass & 6PPC and found that their groups opened up after screwing with the flash holes.....But that was done with only Lapua brass and the formed 6PPC round.........
The primer is a high explosive. It doesn't ignite it detonates. I doubt a few burs around the primer hole slow down a shock wave traveling at over 15,000 fps. I am not willing to remove metal from the inside of the case for some unproven guess work. If Tony Boyer doesn't see a difference with a rail gun in an atmosphere controlled tunnel that's good enough for me. I think a lot of the best shooters in the country don't worry about things discussed on this website. Read the articles in the TechnicalShooter section of this website and see what the the best in the country do. Too much worry about I need to do everything that's possible to a case and no talk about bench and shooting skills. Records are made at the range not in your basement measuring 10 different things on a cartridge case.
Bryan saw no difference in deburring flash holes that had been drilled - Lapua. But on punched flash holes 2 out of the 3 showed improvement after deburring and the third one showed no affect either way.
Yes, we all tend to like to talk in generalities like all reloading components are the same and so should be treated the same - I think this is the reason there is so much debate on topics like this and annealing.
I've never seen a burr in a Lapua but have seen some pretty big and nasty burrs in LC cases so be very mindful of someone's recommendations because it could depend a lot on what they use. Here is a photo from Zediker's book on "Handloading for Competition" You can see the crown like burr inside and yes he does recommend deburring.
I've never seen a burr in a Lapua but have seen some pretty big and nasty burrs in LC cases so be very mindful of someone's recommendations because it could depend a lot on what they use. Here is a photo from Zediker's book on "Handloading for Competition" You can see the crown like burr inside and yes he does recommend deburring.
It depends on the brass. I never deburr Lapua, Norma, or RWS. I will uniform the flash-hole from behind using the Sinclair tools to 0.061" / 0.081". With these makes, that's usually wasted effort, but just occasionally an undersize one appears that needs a lot more effort to ream. One box of Lapua 223 had three really, and I mean really, undersize flash-holes that would have ruined ES/SD values in this little cartridge. The small diameter holes in 220 Russian / BR / 6.5X47L are really consistent though IME.
Some American makes though ........ Deburr? Hell, yes. I find it astonishing that people say they've never seen a burr - a small intense flashlight beam at an angle though the flash-hole from the primer pocket end usually shows some burrs, and often some very large spikes left - they will angle the jet of flame and hot particles from the primer to one side of the powder column.
Primers are explosives and won't be affected by a burr or two as claimed in post #13. You think this pair here getting on for 1/8th inch length and both partially covering the flash-hole would have had no effect?
Some American makes though ........ Deburr? Hell, yes. I find it astonishing that people say they've never seen a burr - a small intense flashlight beam at an angle though the flash-hole from the primer pocket end usually shows some burrs, and often some very large spikes left - they will angle the jet of flame and hot particles from the primer to one side of the powder column.
Primers are explosives and won't be affected by a burr or two as claimed in post #13. You think this pair here getting on for 1/8th inch length and both partially covering the flash-hole would have had no effect?
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Shynloco
You can lead a horse to water, but ........
+1. I too use Lapua, Norma and occasionally some Lake City Match, I check the flash-hole exactly once, when it's new. I think where this notion of having to over check the flash-hole comes from a misunderstanding of the teaching of some of the best shooters around when it comes to the topic of "UNIFORMITY." Though we strive for "UNIFORMITY" and limiting variables, overkill in an area like flashholes isn't going to improve your target score.
Alex
Yes, we all tend to like to talk in generalities like all reloading components are the same and so should be treated the same - I think this is the reason there is so much debate on topics like this and annealing.
I've never seen a burr in a Lapua but have seen some pretty big and nasty burrs in LC cases so be very mindful of someone's recommendations because it could depend a lot on what they use. Here is a photo from Zediker's book on "Handloading for Competition" You can see the crown like burr inside and yes he does recommend deburring.
Do you really need to remove that much metal to get rid of the burr? Compare the size of the burr on the left to the chamfered hole. I would think a few light twist of the tool would remove the burr.
The most I do on new brass (regardless of make) is let the tool virtually hang in the flash hole by its own weight and turn it to see if there is a burr to snag on. If so the lightest touch cuts the burr out. I'm a big believer in NOT altering the flash hole by cutting an internal bevel. I have no proof or clue if cutting it as in some above pics is harmful....but I just don't do it.
It’s like any reloading tool which is adjustable you can decide and fix the amount of the flash hole you remove. Comes with a cone on the handle that acts as a stop on the case neck enterance that you adjust to consistently remove what you don’t want.
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