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Deburring the flash hole.

bruddah

Sergeant
Full Member
Minuteman
Jun 9, 2010
607
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Oregon
How important is it really?

At what range might you see it make a difference?
 
How important is it really?

At what range might you see it make a difference?

I do it and sleep better at night. It's a quick, one time deal for my target brass.

Not all flash holes have a burr. Some burrs are pretty damn long, but it's tough to do an A/B comparision, since you can't go back to the original state and measure things.

Chris
 
A) Don't know,

B) Can't say.

For simplicity's sake, I determined long ago that reaming flash holes appeared logically useful, and that the process was simple enough to just go ahead and do it anyway.

I use Lapua (6mmBR) brass for my .30BR and I think it's everything people say it is. My other chamberings use Rem, Win, and PPU brass, and I ream the flash holes.

I have even resized and reprimed TulAmmo Steel Boxer primed .223 cases, even using them completely successfully for match loads; but I'm not going to put my flash hole reamer at risk in those cases. However, the lack of reaming does not appear to have impacted those 'steel' cases' accuracy capacity noticeably.

Greg
 
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I don't believe Winchester cases have burs like the Federal cases.
Why does Federal Gold Medal Match Ammo shoot awesome with the bur?
Why do people feel the need to remove it if Federal seems to be fine with it?
Don't waste your time.
 
I don't believe Winchester cases have burs like the Federal cases.
Yes they do.
Why does Federal Gold Medal Match Ammo shoot awesome with the bur?
Does it? I use FC cases for my 308 and they shoot better with it removed.
Why do people feel the need to remove it if Federal seems to be fine with it?
Are they? For me it's not 'fine' with the bur or more correctly it's better without.
Don't waste your time.
I really hate when this is included. By that I mean I would eradicate it from forums. It is an emotional substitute for "listen to me and do what I say". My reaction is like a red flag to a bull.

For posters who say it does nothing. Your accuracy sensitivity may not be the same as the original poster. The most appropriate contribution would be "I don't and it works for me" or "I do and it works for me".
 
I don't believe Winchester cases have burs like the Federal cases.
Why does Federal Gold Medal Match Ammo shoot awesome with the bur?
Why do people feel the need to remove it if Federal seems to be fine with it?
Don't waste your time.

Obviously, FGMM doesn't shoot all that great when compared to hand loaded ammo, does it?

All brands of cases have burrs IME and that includes Lapua and Norma cases, which I've deburred.

Well...maybe not Nosler, which hand finishes its brass, IIRC.

Some are worse then others, though, no doubt.

And no, Lapua doesn't drill the FHs, they form them around a mandrel and one can still get some schmutz around the inside.

Deburring FHs would be the first task I give up, but it's so fast and easy to do on my RCBS TrimMate, that I feel guilty not doing it.

You obviously, think differently.

Chris
 
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I used to do it then started testing brass that was done and ones that weren't and saw no differences in accuracy, velocity, spreads etc. I shoot alot of factory ammo that isn't done and that's what got me thinking and testing. You can do it if it makes you feel better but I don't bother anymore as my time is more important.
 
I used to do it then started testing brass that was done and ones that weren't and saw no differences in accuracy, velocity, spreads etc. I shoot alot of factory ammo that isn't done and that's what got me thinking and testing. You can do it if it makes you feel better but I don't bother anymore as my time is more important.

same here , man o man does it save time prepping cases

I use lapua brass mostly and haven't seen the need , I did have a lot of federal and win brass that I would fully prep, but like Rob says factory match ammo shoots fine w/o it being done, I did just pick up a box of 50 nosler brass, and it comes deburred already
 
Whatever you do, don't get the RCBS tool, my winchester brass dulled it right away, so I don't debur anymore because my tool was a pos.
 
Deburring the flash hole also uniforms the flash hole diameter so its two operations in one. The Possum Hollow type Flash Hole Deburring Tool has a positive stop on the shank of the tool and you will not over remove brass in the flash hole with varying web thicknesses of cases.

Possum Hollow Deluxe Flash Hole Deburring Tool

BUT deburring the flash hole is just one step in uniforming your cases.

See step 6 below and the flash hole and primer pocket uniforming tool used.

Complete Precision Case Prep within AccurateShooter.com

On my AR15 reloads I do nothing to the cases other than resize and trim, on my .223 bolt action with a 26 inch bull barrel the cases get the full prep treatment as above.
 
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Some brass manufacturers (such as Lapua) drill their flash holes. Most, however, press the flash hole into the brass, which creates burrs or flaps on the inside of the flash hole. If not removed, these burrs and flaps can shield a portion of the powder from the fire, which leads to inconsistent combustion from one case to the next. I use Lapua brass, so it isn't necessary. When I do use other brass, however, I deburr the flash hole (if for no other reason than peace of mind).
 
I'll simply say that I typically load in increments of 50 cases, and early on, like 15 years ago, I shot a group of 50 cases at 300 yards, just looking for overall group sizes. I shot the same group of 50 cases with all the same load specs, after deburring all 50 cases, and they grouped tighter after the deburring. Also just FYI, Lapua drills all their flash holes, so no need to debur Lapua stuff. Norma punches their flash holes in Non-Magnum case, drills Magnums. Win and Fed both punch so definitely burrs on those mfgs. I convinced myself that the quick one time and it's done for the life of the case was simple and quick enough, and made a difference that it's worth doing a long time ago.
 
The only time my debur tool goes near my primer pockets is when I'm removing a crimp.


Just remember. A little goes a looong way. Too much and you'll cut your primer pocket life in half.

As it being a necessary step to most no. I've never done it again accept for crimp removal of mil 5.56 brass. Like those who trim every pass some sleep better at night doing so some don't care.

Up to you how important it is.
 
I debur just from the standpoint of consistency among brass. I won't for AR brass just because I go through a lot of it, but for precision rifles absolutely. Same reason for turning the case necks as well.
 
Some brass manufacturers (such as Lapua) drill their flash holes. Most, however, press the flash hole into the brass, which creates burrs or flaps on the inside of the flash hole. If not removed, these burrs and flaps can shield a portion of the powder from the fire, which leads to inconsistent combustion from one case to the next. I use Lapua brass, so it isn't necessary. When I do use other brass, however, I deburr the flash hole (if for no other reason than peace of mind).

Actually, according to a Hide member some years back, who toured the Lapua factory and watched the different stages of brass production, they don't drill the holes, they form them around a mandrel.

While not as prevalent, Lapua brass does indeed have 'some' burrs to it.

It takes me three seconds to deburr a flash hole on my TrimMate, so a box of one hundred takes me five minutes and then it's done for the life of the case. I don't do it to my plinking brass.

Chris
 
The only time my debur tool goes near my primer pockets is when I'm removing a crimp.

Yep. Pretty much the same here (occasionally I'll get a wild hair and do it for no other reason than that I can). It does helps achieve a more uniform swaging when removing the crimp from military brass.
 
Haven't tried deburring yet but plan on picking up the tool just to try. Want to see if I can tell a difference, probably won't but I'll see.
 
I fail to see a reason not to? It doesn't hurt a damned thing and attempting to prove a benefit is a fool's errand, in my opinion. For me, it's an attempt at uniformity. As somebody said, if for no other reason but peace of mind. I always go the extra mile, and in this case it's such a small effort among many details in processing my brass that I would not begrudge the effort. However, I also would not advocate it for anybody else. I can't prove a benefit and it becomes an article of faith...kinda makes sense though. BB

PS At the end of the day, for those people inclined to weigh and segregate their brass, that little pile of chips left in the drink coaster does weigh something and it does contribute to case capacity, however minutely.
 
If it makes you sleep better at night do it, if you shoot br then do it, other wise I don't see a noticeable difference. My dad does it but I haven't in a while so I guess one of us will find out sooner or later.
 
My guess is (and you can correct me if I'm wrong), that if de-burring the flash hole makes a difference, you will see it in velocity fluctuations. Correct?
 
The only time my debur tool goes near my primer pockets is when I'm removing a crimp.


Just remember. A little goes a looong way. Too much and you'll cut your primer pocket life in half.

As it being a necessary step to most no. I've never done it again accept for crimp removal of mil 5.56 brass. Like those who trim every pass some sleep better at night doing so some don't care.

Up to you how important it is.

I do believe we are referring to deburring the INSIDE of the flash hole, which has nothing to do with removing crimp.

When I load for all out accuracy, I uniform and de-burr the flash hole, along with a whole bunch of other things, makes me feel all warm and fuzzy.

Now, if I could just hit something...
 
Brass prep is something that i no longer do
I read several comparisons over the yrs and nothing ever imperically showed an advantage to doing it
Clean and stuff with powder,bullet etc
Less time massaging brass and more trigger time seems to show more gains
each to his own method of madness when it comes to reloading
 
Actually, according to a Hide member some years back, who toured the Lapua factory and watched the different stages of brass production, they don't drill the holes, they form them around a mandrel.

While not as prevalent, Lapua brass does indeed have 'some' burrs to it.

It takes me three seconds to deburr a flash hole on my TrimMate, so a box of one hundred takes me five minutes and then it's done for the life of the case. I don't do it to my plinking brass.

Chris
Interesting, Chris. Thanks for sharing.
Bob
 
my thought is this, if you sort cases according to weight, then you should perform all the uniforming steps you can to get the most consistent results from said weight sorting. That eliminates more variables as I see burrs in about 50-60% of the 1x cases I prep. I understand leaving the burr, but if you take the time to sort cases then I would say you should deburr as well as PP uniform ect beforehand. This opinion is based completely on anecdotal theoretical hypothesis so take for WIW.
 
The funny thing is is that even if Lapua brass is drilled, have you ever drilled through even soft metal and looked at the other side of the hole that you just drilled?

Burr city.

Chris

This can be true depending on the process.
 
The funny thing is is that even if Lapua brass is drilled, have you ever drilled through even soft metal and looked at the other side of the hole that you just drilled?

Burr city.

Chris

Speeds & feeds...
 
i say if you can just do it, it wont hurt any and if anything it will make it more consistant when shooting ....
 
Weight sorting brass really is the biggest waste of time
Weight does not correalate directly to case capacity, so other than the feel good warm n fuzzy your wasting your time.
Your time do with as ya see fit