View Full Version : Flash hole deburring ?

11-22-2015, 08:22 PM
Anyone de burr their flash holes in their brass ? what ,if any differences do you see in group size , etc. ?

11-22-2015, 09:10 PM
Differences??......It's more like removing the variables in the case..

I process more brass in a month than most do in 10yrs. The burrs go from mild to wild real quick to the point that at times I block the flash hole when I remove the crimp using a Dillon swager.

11-22-2015, 09:15 PM
I de burr all of the brass even the pistol brass.
It is a one time thing to do, never checked if it improved on the accuracy.
Started many years ago while shooting Hidh Power matches with a 308 bolt gun, too old for that game now.

11-22-2015, 09:34 PM
I do it once, when new or once fired from factory loads.

I have always been amazed at the amount of material that gets removed when I do this to new rifle brass.

11-22-2015, 11:12 PM
i de-burr my rifle brass (a one time deal) but i'll often get as much material there as what i do length trimming. soyeah if the brass is new to you i'd suggest de-burring, i think you will notice better powder ignition.

11-22-2015, 11:16 PM
I de burr all my brass. use a #1 center drill. it also opens up any flash holes that are under size. Bill

Lead Fred
11-22-2015, 11:41 PM
Have a nifty tool that rounds the whole, and puts a 45 degree canfer on the flash hole.

I do every piece of brass that goes though my shop.

11-23-2015, 12:45 AM
All brass gets it here as well.

I first noticed improvement in my varmint loads. ....... .22-250 and .243 etc.

One day, I was messing around with Red Dot ..... a notoriously dirty powder but a goodie ......... and the thought occurred to me ....... "Why not debur a few flash holes on the revolver brass?" Well, it cleaned up 'ole Red Dot pretty well and the rest is history ....... better burn ... better mileage!

Three 44s

11-23-2015, 08:00 AM
Ok sounds like it's worth a try . Can't hurt, but witch cutter to use . Not trying to mess up the thread , but more details please . Easley tested 20 rounds before and after.I am very interested because I have started using more military brass , getting harder and higher to just order New brass.

country gent
11-23-2015, 10:20 AM
You can buy the tool to deburr flash holes from several places. or you can make one yourself. A center drill Small uone 1/8" body or smaller. A piece of 3/16 dia cold roll round stock, a short piece of 1/2" cold roll round stock, and something for a comfortable handle. drill a hole in one end of the 3/16" round stock 3/4" deep or so .002-.005 smaller than center drill dia. face ends square. machine a taper with leaving straight section 1/4" long on 1/2" rd stock. drill 3/16 hole thru and drill and tap a 6-8 32 hole to lock in place on shaft. This can be made caliber specific but you need to make more then. 3/16" round stock needs to be long enough for longest case plus the tapered guide and 1 1/2-2" to go into handle. To assemble drill a pocket in scrap steel blocj to depth of center drills cutting area. open drill hole .005-.008 with a drill. Use this block to support center drill and press into hole in 3/16 rod. Install tapered guide. glue into handle.

11-23-2015, 10:49 AM
I deburr flashholes on most everything. I've run across burrs that almost block the flashhole. I am always surprised at how much brass is removed. Subjective observations give me about 1/4" to 1/2" group reductions at 200 yards with most rifles, more at longer ranges. The observation of very heavily burred flashholes got me started. In the military as an ammo officer I saw more than one cartridge without a flashhole and many misfires that included almost closed flashholes in both 5.56 and 7.62. Quality is better now that late 60's.

bullet maker 57
11-23-2015, 11:23 AM
I deburr all my rifle brass.

11-23-2015, 01:13 PM
I de-burr all my rifle brass, new and fired by others, for my shooting and loads for those few that I load for. I had a bench rest shooter put me onto this trick. It does make a difference in the flame from the primer firing start a more uniform burn in the powder. RCBS and Lyman offer tools to do this chore. With my RCBS case prep station machine it takes most of the work away from your fingers.Robert

11-23-2015, 05:28 PM
I appreciate the detailed information ( country gent ) but I am not very handy at making things. But I think I will give the rcbs or lyman a try . I have thought of it in the past , but put it off . Now I think is a good time to try it out . I am working on a couple rifels I may be able to see the difference with. I am using some Federal 300 mil brass, 762 L.C.lr necked down for a 243 ,and 223 from LC brass. Some of my rifles shoot tighter with a little thicker neck. DON'T worry gentlemen I am very careful with safety . Thank you.

11-23-2015, 07:34 PM
The tools made from a #2 center drill for this purpose tend to bounce up and down a lot when deburring Remington brass.

Remington brass has punched flash holes and they tend to have a large funnel or crown of burrs on the inside.

I deprime my brass by hand using a Lee hand punch and a 8 oz dead blow plastic hammer.
After knocking out the primer I give it another whack to smash the burrs down flat. When mashed flat they make a right angle at the edge of the flash hole after being bent over. Then they are very easy to cut with the flash hole deburring tools.

11-23-2015, 07:49 PM
If it is brass, has one hole, and is not plugged up, I reload it and shoot it. I rarely ever mess with flash holes as I have not seen any need unless gunk is definitely there.

11-23-2015, 08:34 PM
Lyman makes a great flash hole de-burr tool that also threads into their case prep center stand (8-32 threads). it'sthe tooli use tode-burr

country gent
11-23-2015, 09:16 PM
Like a drill bit or mill used in brass a little work with a very fine stone stops alot of the chattering. The tool would perferably have 3 or 5 flutes so the cutting edges arnt in line with each other. Most fight drilling brass and soft materials, these require diffrent relief angles than steels.

11-27-2015, 12:48 AM
deburr all my brass and you only have to do it once. you'd be suprised at the amount of chips from some of the burrs around the flash hole. Frank

Lead Fred
11-27-2015, 01:14 AM

A simple hand tool is all thats needed. I have a different companies, wooden handled, but works the same

11-27-2015, 08:30 AM
I use a dedicated tool made and purveyed by Sinclair exclusively for deburring flash holes. A second step I do is uniform the flash hole size -- I find the size variation from lot to lot, and brand to brand of same caliber brass amazing! Lastly, I use a tool called a "crocogater" which, with a few quick twists of the wrist, further uniforms pocket depth. 'Specially with gas guns, that the primer *IS* seated below rim is imperative! Like others posting, I too have not done a "no" versus primer-pocket-cleaned comparison vis accuracy results. But, I do feel better about my loads with the flash hole deburred, a uniform hole size, and pocket size to ensure below-rim seating.

11-30-2015, 12:01 PM
I have a deburring and uniforming tool but is seldom gets used unless I spot an unusual flash hole. I'll occasionally find one with a lot of burrs or an excessively small flash hole. Then the tool gets used.