Read on another site where a person had finished deburring flash holes on just acquired brass. Got to thinking is deburring flash holes really necessary. I used to do it but the past few years the only thing I do to new brass is chamfer the case neck. I can't tell any difference in accuracy or velocity.

What say you?


Deans

Waste of time and brain cells.

Depends on the brass and your intended purposes

I do it for peace of mind. Do all you can for CONSISTANCY. It does not take long to do, and you can feel some that are really bad. Does it make any difference? I like to think so. Good shooting.

I do it with one cartridge, my 6mm PPC benchrest rifle--but have never actually tested whether it made any difference. After all, a primer's flame is a LOT longer than the flash-hole, even one with a considerable "ridge" around it.

But quit doing it with all other rifle cartridges years ago, due to finding too many grouped extremely well without it, including light big game rifles that would put 5 shots into half an inch or even less at 100 yards, not just 3 shots. Would deburring the flash holes reduce those groups significantly? I doubt it.

Try it with sub par brass and past 500 yards thats the true test, the farther you shoot the more things matter

For my purposes haven't noticed a difference

It probably doesn't help any, but then again, it doesn't hurt anything either.

I use to deburr brass but I found it was an exercise in futility with no appreciable benefit for my hunting ammo.

It all depends on what brass you are talking about and what condition the flash hole is from the factory. If its real rough and not a nice clean flash hole, I'll "debur" it. If it doesn't have burrs, don't waste your time. I've seen some schidt factory flash holes that had to be deburred and also hit from the inside with a tool as well. New Winchester brass comes to mind. One of the reason I don't buy the chidt anymore. Lapua: no you don't have to mess with the flash hole.

You are probably using pretty good brass too, to start with. That makes a huge difference.

BOOM!!^^^

What can it hurt? You only have to do it once.

Necessary no . Does it hurt anything No , will you notice it with most rifles probably not. Very accurate interest type possibly every little bit helps in that game.

The various tools are inexpensive and the small amount of time spent is minimal……it can’t hurt! memtb

I've always thought it was just one of those incremental things that can help with accuracy along with all the other steps we take. I've deburred a lot of flash holes inside and took off quite a bit of brass from the burr. Others there is almost no brass removed. Draw your own conclusions but I've always though anything you can do to create a uniform ignition flash that is unobstructed by debris can't hurt accuracy. Like said above, you only have to do it once.

I suggest that you at least inspect the inside of the cases especially if it is a first use. I have found string burrs (.5 - 1 inch long) in Lapua brass, heavy burrs in Winchester... this is just with my limited experience as a handloader.

I always do the flash holes. I was taught by a benchrest shooter.

I like to do it only because I had a piece of brass once without a flash hole punched in it at all. It was easily noticed while reaming the flash hole.

I just bring em to my armchair and clean em up while watching the TV.

Been reloading for 30 years. Never deburred a flash hole in my life. Never had a problem finding sub MOA loads on every rifle I’ve owned…many of them sub-1/2 MOA.

Just my experience.

Leftybolt

We all load "sub 1/2 moa" loads. Shouldn't even be brought up as a criteria. Just the funny thing is you all say it, but no one can prove it.. ha ha.. However, at least checking the flash hole should be a something a good handloader does.

Never had a critter stand there and laugh, "HaHa, you didn't deburr your flash hole!".

Why would anybody use "sub par brass" if they intend shooting big game past 500 yards?

i agree with what Mule Deer does , my bench rifles i always check new lapua brass , i do also check my long range hunting new brass i use on big game, not all of this brass is Lapua because Lapua does not always make what cartridge brass i need like 257 Weatherby brass so then i have to check and deal with each piece of brass and it can be very tedious and boring as heck. but doing this type of inspection and working with each brass case you decided to keep you can have some very good brass to use to hunt with confidence for that one shot. here is a short story about a buck antelope i shot ,i knew the distances of this big alfalfa field in Wyoming i crawled up this small hill and when i got to the top of this grassy hill , i could see at least 75 -100 antelope and one very nice antelope buck with big cutters standing at 625 - 650 yards so with my rifle laying down with my short Harris bi-pod i got ready for the shot with my rework silver plated Federal brass that was weighed and neck turned too. this rifle had a custom Lilja barrel with machining done by Jerry Siminson including the 257 Weatherby mag chambering , i did all the stock bedding work and trigger set at 1 1/2 lb. with a 6 1/2- 20 x50 leupold this Remington 700 shot very fine . i knew i only would get one decent shot , i had been practicing out to 700 yards . so i took the shot with this rifle this bullet was a 100 gr. Nosler Partition velocity was 4,000 + check with my conograph too. buck went down so fast and all the rest ran away very fast. this buck had 7 inch cutters and was 14 1/4 long best i ever have taken . so its possible to inspect regular brand brass and end up with some good brass but Lapua brass is still the very best made.

Vital if you just so happen to be OCD and A-R...

I have read that it is more important to deburr & uniform flash holes if you are using ball powder... So i now do it if ball powder will be used... Dunno if it makes a difference or not... But i at least check all flash holes for problems...

Yep! But I am OCD and A-R enough to have compared the results with the same big game loads, with and without deburring the flash holes, and never could find any difference, even in super-accurate rifles, whether factory or custom. The reason for that? I handload more than most hunters, and am very happy to save bench-time by NOT doing stuff that doesn't make any difference....

Agree on Lapua - also Nosler and Peterson

RP and Win definitely get deburred.

20 cases can be done in 10 minutes and it only needs to be done one time.

There ya go MD spouting logic and common sense. Out of the hundreds of millions factory big game ammo that’s produced and sold have the flash holes deburred? I am sure that Hornadys American Whitetail ammo which all laud as superbly accurate have to have each and every flash hole hand inspected and deburred.

🤣

Complete waste of time.

I do them for the hell of it, probably makes no difference at all.

When theres nothing else available thats why.
I started shooting 6.5x300wsm over 15 years ago and had to prep the crap out of Win. 300wsm brass to get rid of unexpected flyers.
Now that I shoot ADG 300wsm in it not a problem.
This is why my original statement was depending on brass and intended purpose.

Total waste of time. Rio7

It is a thing that bench rest shooters do and I believe it serves a purpose for that game. For anything else , no . If it were really needed it would be done at the factory. I do it on all of my bottle neck cartridges with the exception of Lapua, Sako, and Norma which are manufactured with no burr . I don't really need to do it but I have the tool and it is no big deal time or labor wise .

Peace of mind is why I do it too. I usually load 100 cartridges at a time, so it doesn't take long to debur those case and once done, it doesn't ever need to be done again. I don't know that doing this improves accuracy, but it doesn't seem to hurt accuracy, and it is part of my process, like trimming all cases to the same length. Being retired for almost 1/3 of my life has provided the time to over-do some things that a person with less free time might choose not to do.

When I get a new batch if brass, whether brand new or once fired I generally trim to the "trim to" length, chamfer the necks, ream the flash holes and uniform the primer pockets.The last two are a one time type of task so why not? Does it do any good? Damned if I know. I like to think it does, so I do it. It does eliminate some of the variables.
Paul B.

Yep, Johnny's right on again. I DID experiment with several uber-accurate varmint rifles and deburred flash holes made no difference at all ... at least, within statistical bounds.

Sometimes we work ourselves silly trying to achieve better results. Often it works, but almost as often, it doesn't.

Blessings to all,

Steve

PS. To those who care, I'm still fighting the bad stuff and apparently not winning. COVID-19 vaccine killed my auto-immune system and it's been the fourteen months from Hell. Honestly not sure I'm going to make it. S.

You said uber accurate varment rifles, ive got dozen or so varment rifles also that I dont deburr flasholes either.
But when you start in with LR hunting and BR rifles little things matter so there is a difference in rifles and intended purpose.

I do them, as I usually do them when the wife is watching something on tv I don’t like. Honestly as BSA mentioned good brass doesn’t need it.

I only do it for a couple of my most accurate rifles with small capacity cases such as a 22 Hornet and a 221 Fireball.

If you’re gonna do it you have to make sure you’ve got a good reference for the cutter. Mine is a Lyman and it has a cone shaped, length stop. With it, I do it right after trimming to uniform length. That way I have the cone bearing on a 90 degree edge on the inside of the case mouth as a reference.

I uniform one case to set the stop and then mount it the tool on my case prep machine along with in/out chamfer cutters and go to it. It only takes a couple of seconds and I’m not loading for a ground squirrel or PD shoot.

I don’t think that it makes enough difference but it makes me think I’ve eliminated all variables on the little ones

. Example of one…I did a test with one of my 308 40-XBs. I uniformed the flash holes of 5, uniformed the primer pocket of 5, uniformed both flash holes and primer pockets on 5 and five I loaded with no modification.

I marked each batch but for whatever reason, it was a while before I fired them so it was sorta like a “blind test”. The winning group (200 yds) was one with the “stock” brass. 😳 oh well….

If anybody here hasn't heard of the semi-famous (at least among benchrest shooters) "Houston Warehouse Experiments," the were conducted in a 325-yard long warehouse, where the were no variations in wind, light etc. PRECISION SHOOTING magazine published an article on them, and it can also be found on the Internet if somebody wants to read the entire thing:

https://precisionrifleblog.com/2013...house-lessons-in-extreme-rifle-accuracy/

But the major points Virgil King (the benchrester who owned the warehouse) found after considerable experimenting by him and other benchrest shooters, were:

Myths Busted:
Powder charges, as long as they were fairly consistent and bracketed within a couple of grains, were not important. He threw all of his charges with a Belding & Mull powder measure, and for one experiment he shot groups using three different powder measure settings (51, 52 & 53) … all three groups were identical.
Lot variation in powder didn’t seem to have any effect on accuracy, even on when using IMR 4198, which has a reputation for varying considerably from lot to lot. He would just buy powder as he needed instead of laying in a big supply, because he found no evidence to support that powder lot variance affected accuracy in the least.
He never saw an inaccurate primer, and was unable to detect any accuracy variances resulting from seating pressure.
Rumors have persisted for years that some rifles shoot proportionally better at 200 yards than 100 yards, or vice versa. Virgil files that one under “occultism.” His experience in the warehouse was, if a rifle was shooting a consistent .100″ at 100 yards, it shot a consistent .200″ at 200 yards.
He did NOT uniform primer pockets.

This may all seems radically different, but for decades some of the common benchrest stuff that made it into major gun magazines was also BS, at least in the long run. One big fad for a while was cleaning bores every X number of rounds, often around 20-25, but sometimes other numbers were given. In fact one loading manual published back then suggested cleaning intervals "for best accuracy" in various cartridges from 10-25 rounds. This may have been valid in their test barrels, at least at the time--when many "accuracy powders" were sphericals that left considerable power fouling. But that has changed enormously since, due in part to major improvements in powders.

As I noted in my earlier post, I do a lot more handloading than the average hunter, the reason I try to stick with what works, and don't do stuff that doesn't make any difference.

But have also noted a number of times that many handloaders prefer to spend more time than they need to on minutiae, because it's a hobby that takes them away from the everyday world. That's great--but that doesn't mean the minutiae actually makes a difference.

This needs to be a "Sticky" this type of question arises in one form or another fairly regularly and this does bust a few reloading myths. I like it because I didn't know it was true because of the experiment, I just found out that not doing all that stuff let me hit an amazing amount of critters, and let me load for volume and not for taking time to do all the small stuff, including hand priming...

Will add that King did uniform flash holes--but apparently never tested whether it made any difference, like a lot of shooters today. More interesting was his observation that the primers didn't make any noticeable difference, as long as it went bang....

We have those exploding rabbits down here too. 4ft elevation with a 308 and 20ft with a 375H&H.

Withdrawn, I missed part of the discussion.

Wouldn't a flash hole burr cause turbulence and provide better mixing of the flame into the powder and enhance consistency?

Deans: Been doing so on all my new brass for all my Rifles for MANY decades now.
It needs be done only once and takes just a moment - you would be amazed at some of the shards of brass I remove!
And I, also, have never tested un-deburred vs. deburred so have no first hand knowledge of its accuracy merits.
I have also been known to use another of my Whitetail Designs tools to "uniform" my primer pockets, on several different cartridges for my more accurate rigs.
Again only needs to be done once.
I tend to think like "Mauserand9mm" - some of the shards I have removed lead me to believe some type of interference would have happened?
Hold into the wind
VarmintGuy
P.S.: Which brass producer used to advertise (brag?) that their flash holes were drilled and not "punched" thus precluding the need to deburr their flash holes?

Doggone it Steve, I hope you can find something that gets you back on your feet soon...

I have read the Houston Warehouse article a few times. I would not dispute Mr. King's findings, but things that make no difference at 325 yards, like a 2 grain powder variance, could certainly make a difference at 800 - 1,000 yards.

I deburr mine just because. At worst, it does not hurt anything. At best it may help

Remington bulk from Midway 6-7 years old



04-05 Winchester



Norma




Now if any of you out there have a teslong, snap a pic of the flash hole before and after. Those were all just grabbed out of bag or box and right now I can’t see anything that would impede the burn especially since the powder is going to sit right in that large hole and the bowl around it.

Better things to do with my time than deburr flash holes.

It has been my impression that most people who do any volume of reloading eventually find a process that works for them and once in that groove usually don't stray far. Keep the burr or remove the burr, the "right" answer is whatever is "right" for you.

Yep. It takes me about 5-10 seconds for the average case, and only has to be done once. I don't see a whole lot of down side.

If you believe primers doesn't make a difference in load development then you just keep believing all those magazines you read.
I shoot alot and I know for a FACT primers make a huge difference

I dont do that crap, i also dont mind if someone wants to eat a package of saltine crackers in my pickup either ; ]

I'm no benchrest competitor, and don't pretend to be one or speak for them, but everything I've read seems to indicate that current benchrest shooters still clean bores religiously, and would probably disagree that it is BS for their particular sport. Of course, for the average shooter with the average sporting rifle, I'm guessing there probably wouldn't be a discernible difference if one cleaned every 100 rounds or every 20.

"Cough...shy look around the room...thats me, lol"

If the rifle is itself put together well, accurate, I have seen 3 shot groups tighten up, "with my components in handloads". IOW, if the rifle is very accurate and the handload is very accurate to start with. The only exception I have seen ( at least since I first learned about Uniforming Primer Pockets/Deburring Flasholes, sorting brass by weight and BR Primers, in 1988) was a Sporterized 1917 Enfield my Uncle gave me when I was 16. I kid you not, 3 shots for sure, five shots "very often" with 150 to 200gr (Pro Hunters) Sierras and IMR 4350. Cut my groups in half.

Don't think that is what he is saying at all, stating what another perosn observed.

Also pretty sure he isn't reading much of his own writing as well.

When I used a Dillon B for 45 ACP, I never cleaned a primer pocket or deburred anything! Back then I would load 500 at a time for some Courses/Training my and a friend were taking, shot 250-300 a day for 2-3 days.
If I load on my RockChucker Press, say the 45 Colt, I'm back to scrutinizing, messing and gumming with it , lol. "The Puddle knows what I speak of"! ha

Not disagreeing w anything you posted but sometimes a particular rifle will shoot whatever load is shot in it no matter the combination as long as that combination was suitable for that cartridge.

Some won't.


I had a 22-250 that I shot 40, 45, 50 and 55 grain bullets in, various manufacturers/styles as well as IMR-4064 and 4895.

I could load 5 different weights/styles of bullets in front of both powders and that rifle would still keep all bullets in a 1" or better group. Even when sighted in with 1 combination and shooting 1/2" groups it would normally put a group of a different combination within 1/2" of sight in load, some loads never required resighting.

Very unpicky rifle.

Don't you have an exploding crow somewhere?

Not required at all, but something for us to do if one wants extremely consistent ammo.

When I got the 1050 did an experiment. Took 300 once'd RP nickel .45 ACP cases and ran them out. 231, 230 gr .452" sized (you probably know why), WLP.

Never trimmed, never primer pocket cleaned. By the time I broke 100 reload cycles had just under 100 cases left. Primers seated just fine.

However.........am now using mixed brass find some WCC and other mil brass benefits from a primer pocket cleanup every 8-10 loadings. To get primers flush.

Then why even post some so called test.
I encourage everybody do your own testing and don't believe half what you read in magazines or internet and come to your own conclusions.
Besides I believe that test was 30 years ago, things have evolved by leaps and bounds today.

Necessary? How about essential?

John, didn't I say something about guys like this around 2015?

Because it would take years longer than I have to spare to do all the testing others like Mule Deer (John Barsness if you aren't aware) have done already for our benefit. There are a few people I trust to put out reliable information and Mule Deer is one of them. Reading the articles is one thing- knowing how to separate the wheat from the chafe is another thing altogether... over the years we have been blessed on this site with some very knowledgeable experts in every sense of the word to be able to gain their knowledge that was freely offered. Accepting that information is up to you.

Like I said test primers and come up with your own conclusions. Takes very little time, then you will know how to separate the wheat from the chaffe.

Its fine being " that" guy.

Some of you that think the Houston Warehouse "test" is the Bible of shooting and reloading go over to accurateshooter and read the thread that was started on it and see what some really good shooters over there think of it.

This is it.

I used to do it. Now only IF a flash hole isn't open enough.

That is it. Only once and it just simply eliminates one more variable. I am doing all of the other prep anyway so I just do it too. Just makes me feel better even if it does not make much of a difference. Part of why I handload is knowing EXACTLY what is being done to each round. YMMV

sherm 61,

Of course there's more to it when shooting in wind--especially ballistic coefficient and skill at "reading" wind. Don't see anywhere that was contradicted in the warehouse tests.

What they did was test all the OTHER factors in small groups. If you don't understand how that might work, then you don't understand systematic testing of ANY sort.

No what those guys are saying is indoor warehouse is not real world testing because matches are outside.Hunting is outside.
Just like Erik Cortina says a good rifle in tune will shoot better in the wind, you might as well test in it because your gonna be shooting in it.
Why don't you interview Erik Cortina, Speedy Gonzales, Jackie Schmidt or go down to Deep Creek in Missoula ask those guys about tuning.
Just like Jackie Schmidt said there's a big difference between 100-300 yards than 600.
I have the privilege of shooting with and talking to a world record holder whos at the top of his game week in week out at Deep Creek ive learned alot from him and I can guarantee you some things those guys said 30 years ago dont matter DO MATTER of course if you never shoot past 100 it doesnt.

Hell if they have the 2,000,yard shoot in Lewiston and you dont want to go to DP he will be there ill even ask him if he will do an interview with you then you can ask him if Primers and flasholes etc. matter. You can even ask him how he preps his brass tunes with powder, seating depth, anything you want. Of course he won't tell you everything but if you'll listen you will find out the sifting through the chaff so to speak

Good post JB. I actually liked that article. It was nicely done. They take some variables out of the equation, which is a good thing when testing accuracy/precision. That way you know exactly how precise your system is. Makes sense to me.

After reloading for over 30 years and by latest count 101 different cartridges, IMHO, no it is not necessary.

ya!

GWB

Sherm 61: IF.... you are saying that shooting for accuracy and accuracy testing, in "dead air", inside a building, has no value then YOU are WAY, WAY, WAY off base!
I don't care who you know or talk to.
Why on earth do you think accuracy minded shooters traveled the distances they did to get a turn shooting in that long warehouse?
Prove the equipment and the load components in dead air THEN learn the wind.
And I am NOT impressed by your contention that someone thinks "that a good Rifle" somehow knows to prefer to be shot in the wind because it attains better accuracy in the foibles of the wind than it would in dead air???
Sheesh.
Hold into the wind
VarmintGuy

You have a PM.

I doubt Cortina really said that, unless he was 3 sheets to the wind....

Watch his you tube videos.
Some of you just don't wanna believe what was done 30 years ago has long surpassed.
No different than race cars one built and set up then won't even make the race today.
Go to some LR matches talk to some shooters there, most are pretty helpful what they do will translate right to better LR shooting rifles. All you gotta do is be willing to listen.

BSA did you look at the link I provided?
I see it won't open, so just go to accurateshooter read it for yourself. Its right in the Reloading forum.
Please report back!!!!

sherm61: "I" am NOT willing to listen to bullschit.
Sheesh.
You are way out of control - or stupid - or both.
Shakin my head.
Hold into the wind
VarmintGuy

I shoot p/dogs

they don't know the difference between 'deburred' or not deburred cases

Same as primer pockets.....dirty....stuff another Rem 7.5 in & kill another dog

Whats bullshit!! Out of control of what?
Listening and learning from guys who are at the top of there game today.
Doing the same [bleep] you did 30 years ago and not willing to learn from people who show you improvements is stupid and out of control.
I really don't care, but don't feed me BULLSHIT!!
All you wanna do is shoot 100 yards it will work fine for ya
I choose better challenge.

I doubt it matters what VG says. If you don’t mind doing the work then don’t give a thought to what others say. Just keep hammering and as long as you’re confident in your gear who gives a crap.

Sherm, I think there is a lot of validity in the warehouse shoot article. Even today, if guys want to read it. It is an old article, yet still very interesting and still has some very valid information. If I remember right, they were shooting groups in the .0's or less than .1". Something like .025". Now, those tests were not devised to test shooting in the wind. The reason they were inside a building. They didn't want to have to contend with the wind. That gets rid of a variable that can greatly affect precision. And that is what they were doing. Experimenting with lighter weight rifles to see how precise they could make them. I don't remember if they tested deburing the flash hole and its effects on precision. I'd have to read it again. But that is what this thread is about. Not shooting in the wind and how accurate you can be doing that. This thread is more about the effect it has on the precision of the load. Now, I shoot quite a bit in the wind and I don't even know why this was brought up in this thread??? Also, just because a rifle is the baddest azzed rifle in the world, it's not going to shoot better in the wind than it would in a dead calm situation. That's like my buddy that says he can shoot a coyote better on a dead run at 300 yards than he can a target at 100 yards. That would defy physics, so I don't care who told you that, they were literally blowing smoke up your azz and it sounds like you bought in to it. I've been going to longrange shoots for a while and I hear guys talking about how they handload. When I first started shooting with the new crew of about 22 shooters, they talked big. A lot of opinions about handloading. That doesn't mean they are always shooting top scores. Even though they have some pretty bad azzed equipment. Long heavy barrels (try 28-30" and suppressed) and exotic cartridges on custom blueprinted actions. These guys are great shooters with awesome equipment, but I learn more about shooting and precision by shooting different conditions vs. listening to their garble. Everyone has their own opinion on things. My take on flash holes is buy good brass that you don't have to worry about "deburring" the flash hole. I'm talking about a special deburring tool. I had to buy one, just for one lot of crap brass I bought last year. It was 308w brass and I learned my lesson about buying that chidt. Never will again. My suggestion: Buy good brass and you don't have to worry about it. I do, however, keep an eye on the cleanliness of the flash hole. Meaning if it becomes rough or jagged, I usually clean it out a bit with an appropriate sized torch tip cleaner. I use those because they are like a very small round file and take the rough edge out of a flash hole. I think by doing that, it helps the primer do a better job, as the flame will be more uniform and consistent with no burr getting in the way. I may be wrong, but I've been doing that for a long time and I know what works for me....