Uniforming the flash hole, Necessary?


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hsiddall
February 28, 2008, 09:26 PM
Im loading for .308 accuracy, Im using 168Gr Mk's anf once fired federal gold medal brass. Yes the cases are trimmed and chamferred but Is it really necessary to uniform(de bur) the flash hole...(Lyman Hand tool) Will I see any difference???

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Grumulkin
February 28, 2008, 09:48 PM
Premium brass like Nosler brass already has the flash holes uniformed so if you're using that or similar brass, you don't need to do anything more to it.

Even if you're using brass that hasn't already had the flash holes deburred, I doubt you'll notice any accuracy difference after uniforming the flash holes but by all means try it and see. I think having the flash holes perfectly centered is more important and some case brands have a lot of cases with off center flash holes which I discard.

GearHead_1
February 28, 2008, 10:25 PM
I tend to error on the side of overkill. Though most premium brass has no need for it when new, once fired, brass gets the burned powder crusties in the flash hole. Most of the .50 BMG reloaders (they tend to be quite anal) I know would tell you it's an important step. It's not terribly labor intensive and it certainly won't hurt your finished product. I do it on all calibers.

electronrider
February 29, 2008, 12:55 AM
10 bucks for a hand tool, and what, 30 seconds to do the job? I don't see why you wouldn't, unless time is that critical of a factor.

moooose102
February 29, 2008, 09:22 AM
is it necessary? probably not, i do it because it is one more thing i can do to try to make "perfect" ammo, if there is such a thing. it is only a small step, if it was way labor or cost intensive, i would re-think it. at this point, i do it with a drill bit! i chuck it up in my drill, and hand turn the case 2 or 3 turns. it works for me.

Walkalong
February 29, 2008, 10:19 AM
6 PPC for competition is the only thing I have ever uniformed flash holes on. I would do the same for High Power if I did that. Other than that I don't believe it will make a difference that will show up on paper. You would need a seriously accurate rifle to know the difference, and even then, it's more in our minds.

dagger dog
February 29, 2008, 11:46 AM
probably not, probably not , but while your at it go ahead and buy the primer pocket uniformer so you can do another step that you probably won't see any noticeable change in accuracy!

heck why not, i think it's a confidence thing knowing that you have taken all the steps possible to create the most accurate ammo!

rcmodel
February 29, 2008, 12:40 PM
If you believe it will help, it will help.

A lot to do with accuracy is all in the mind.

With that said, I don't even own a flash-hole deburring tool, and have never de-burred a flash hole in my life.

Because in my mind, I don't believe it will help.

rcmodel

ny32182
February 29, 2008, 01:44 PM
How much effect to off center holes have on accuracy? Someone mentioned those before, and I've noticed that some of my brass seems to have the hole off center.

ranger335v
February 29, 2008, 03:08 PM
"Is it really necessary to uniform(de bur) the flash hole..."

Necessary? It may help a little but it's certainly not necessary, the round went off the first time didn't it? In fact, uniforming primer flash holes and pockets are probably the least important factors in accuracy for factory rifles and chambers, right after turning the necks for already sloppy factory chambers.

I do it all anyway. :)

But, I live north of you, between Brevard and Hendersonville, so what do I know?

FM12
February 29, 2008, 07:04 PM
I do it. Cant hurt, and you only have to do it once.

As badly as I shoot, I need all the help I can get.

30Cal
February 29, 2008, 07:07 PM
I haven't been able to measure any difference.

brickeyee
February 29, 2008, 07:27 PM
If you have a gun delivering BR type accuracy it might make a difference.

If you have anything else there are just to many other things that will matter more.

A uniform flash holes and primer pockets, along with turned necks for both of my varmint rifles, .22-250 AI & 6 mm Rem AI

Added 3/1, 10:54A:

Both barrels ARE tight neck. A factory round will not fit (on purpose).

Both hold 0.25 inch 5 shot groups at 100 yards, and the 6mm AI maintains similar MOA out to 400 yards.

My .30-06 Rem 700 BDL holds about 1.5 inches at 100 yards and the deer are very dead.

rodregier
February 29, 2008, 09:07 PM
BR accuracy or distances beyond say 300 yds might show a difference. Norma and Lapua rifle brass already have drilled, not punched flash holes (so they don't need uniforming).

Short of those accuracy requirements, the varibility due to primers and case weight will overwhelm non-uniform flash hole effects.

dagger dog
March 1, 2008, 11:41 AM
Hey,

I forgot neck turning inside and out side.Know it doesn't serve any purpose on non target chambers but man those little gadgets are sure fun to play with!

Ol` Joe
March 1, 2008, 12:04 PM
Hey,

I forgot neck turning inside and out side.Know it doesn't serve any purpose on non target chambers but man those little gadgets are sure fun to play with!

You have to be careful when turning necks, too much off and your sizer may not reduce the neck enough to keep proper tension on the bullet. Most shooters I know that turn necks use Redding sizers with the interchangable "button inserts" of various diameter. These allow the necks to be sized to snuggly fit the rifle chamber and keep enough tension on the bullet. A little bit of turning, just to remove a high spot "may" help with run out but I haven`t seen any gain here either with my brass.

Once you start doing this type of brass prep you need a tight chambered proprly assembled rifle to see any difference in accuracy. We are probably talking of 0.05" or so gain in accuracy with these various steps and they only seem to show up for the benchrest crowd whom can consistantly shoot well enough to see any changes that occure. A factory rifle will show no gain normally from primer pocket uniforming or neck turning.

donttellthewife
March 1, 2008, 01:17 PM
I only do it if I know for sure my wife will be the only one fireing the rounds.

I only reason I do it is so I can tell my buddies that "I have uniformed my wifes flash hole", this gets a good laugh, then the conversation goes down hill from there.:neener:

brickeyee
March 1, 2008, 01:20 PM
If you can find a longer round of the same case head you may be able to make cases with thick enough necks for a factory chamber to allow turning.

Sometimes it improves accuracy a detectable amount, sometimes not.

K3
March 1, 2008, 02:08 PM
I did a bit of neck turning on some rounds for a factory rifle. Each batch was turned 0.005 more than the previous. I found that the neck turning improved accuracy on the lightest setting. On the second setting, accuracy returned to non-turned levels. After that it got worse. This was using the RCBS hand held neck turner.

Conclusion: It works for this particular rifle with the particular load I am using.


As far as the flashhole goes, I have seen an improvement on a couple of deer loads I use. Not much, but a little. I use the Lyman handheld tool, but I screw it into my TrimMate. Now THAT is a handy gadget for only a C note.

My varmint rounds actually suffered a tiny bit.

:banghead: :D

I love this hobby. I am a curious tinkering type, and it suits me.

Walkalong
March 1, 2008, 06:14 PM
Neck reaming and or outside neck turning is only needed with tight necked chambered rifles and sometimes brass necked down from a larger caliber.

scrat
March 1, 2008, 06:25 PM
Ok back to the topic.

Uniforming the flash holes and cleaning the primer pockets is a must for me. Its kinda like running a car with bad spark plugs. Thats pretty much what the primer is. So to keep firing at top performance people use quality spark plugs and change them when your supposed to. Kinda like in racing. I really doubt anyone uses the same spark plugs from last season. So when your at the range trying to set up some prime groups and trying to be or get the best accuracy you can. you need to be on top of your game.

30Cal
March 1, 2008, 07:04 PM
Uniforming the flash holes and cleaning the primer pockets is a must for me. Its kinda like running a car with bad spark plugs. Thats pretty much what the primer is. So to keep firing at top performance people use quality spark plugs and change them when your supposed to. Kinda like in racing. I really doubt anyone uses the same spark plugs from last season. So when your at the range trying to set up some prime groups and trying to be or get the best accuracy you can. you need to be on top of your game.

You can easily measure the effect of bad spark plugs, even on a junker running bad gasoline. I would compare the uniforming of flashholes to the uniforming of lugnuts.

paperpuncher49
March 1, 2008, 08:38 PM
Necessary, No. Does consistency help accuaracy? Yes (for the most accurate bench rest shooters where 1/1000 on an inch matters. For the better than average shooter, probably not.

swiss7.5
March 2, 2008, 10:16 AM
Ok back to the topic.

Uniforming the flash holes and cleaning the primer pockets is a must for me.
Its kinda like running a car with bad spark plugs. Thats pretty much what the
primer is. So to keep firing at top performance people use quality spark plugs
and change them when your supposed to. Kinda like in racing. I really doubt
anyone uses the same spark plugs from last season. So when your at the
range trying to set up some prime groups and trying to be or get the best
accuracy you can. you need to be on top of your game.

Scrat, i got a giggle out of your analogy. that is not like saying you change your spark plugs it is more like saying you rethread the spark plug hole in the cylinder head and if you do that everytime you change your plugs more power to ya.:o

PS. i do at least clean primer pockets after every fire:neener:

oldgold
March 2, 2008, 11:50 AM
In an article in Varmint Hunter Mag the author took 1000 new cases an divided them by weight , then by prep. Some were neck turned, some were flash hole deburred, some were fired then necked sized only.

The biggest change was flash hole burring.

Neck size only gave some small improvement.

Other than these two , his best groups were with an untouched control group.

I weigh cases and debure flash holes. I've also found that , at least for my loads, Lee factory crimp works wonders. I've always thought that crimping with the seating die was a bad idea. This crimp depends an the case length and thickness where as the Lee die presses in from the side.

I'm not great at bench rest shooting but I'm trying to be. This is a constant learning process. I do know that what works well for one gun won't necessarily work for another. Makes it fun.

moosehunt
March 2, 2008, 12:50 PM
My experience is that regarding brass with punched flash holes (not Lapua or Norma), you may get an improvement with the first firing by deburring the flash hole, but generally after the first firing, no advantage. I have observed that if there is a burr on the flash hole, it almost always trims itself with the first firing, the second for sure. No doubt, there could be exceptions. All in and all done, I debur the flash hole on new brass. It is a one time deal. Probably overkill, because new brass is never used for important loads by me anyway. I want it fired once, then I neck size for anything of significance, i.e. hunting.

Lance Boyle
March 2, 2008, 01:19 PM
Not for nothing, the brass from FGMM shot pretty good the first time didn't it?

Like others have said, it doesn't take much to just go ahead and do it. I do it on some heavy barrel rifle ammo but I don't bother on garand and M14 ammo anymore.

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