Home Forums Reloading Big Game Rifles Deburring flash hole --- Necessary?

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