Tiny flash holes...

LiveLife said:

You don't have to but if you want greater "consistency", I would.

Same for checking finished OAL and chambered OAL for bullets setback. Many don't check it and wonder why their group sizes are not consistent.

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I guess you’re saying using all the same size flash holes in 9mm will produce greater consistency among two or more cartridges? I get your point (but have still seen no data) and don’t know that it’s helpful in the real world to do so unless we’re into some precision bench rest stuff.

But that doesn’t at all equate to one should drill out small 9mm flash holes.

The answer to OP’s original question—have we seen different sizes of flash holes in 9mm is—yes, ammo manufacturer’s use various sizes. We know at least two sizes, but beyond that who knows? In 45ACP it’s more than two.

Why? We do not know. Is it a problem? Not as far as any of us know. Do we need to drill out or throw out the small ones? Not as far as any of us know.

Howa 9700 said:

I'm still trying to wrap my head around who carries reloading equipment with them on a bike and stops on the side of the road to use it.

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He never wrote that??

"and back home".

The Glockodile said:

It's all just about physics.

And an understanding of internal ballistics.

I have a degree in Engineering and was a salesman for high - end Thermocouples...

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And your point is??

Where is the data?? We are talking about a couple of 9mm brass cases left out in some shooting range,

What do people do if the flash hole is a little larger? What is a normal hole?

CQB45ACP said:

Okay, but again, why?

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So they can be deprimed with fat decapping stems/pins...

What does NORMA know anyway?. Only been doing this for over 100 years!
At about 3:45 (yes it is rifle brass)

mdi said:

So they can be deprimed with fat decapping stems/pins...

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AKA, wag the dog

Perhaps just a decapping issue. Without specific information from ammo manufacturers regarding the size of that ignition port in 9mm brass it may be just the variance in case manufacture. Off center may be a bigger issue. I haven't come across any data in any of the research I've done for size or the issue of off center. Ignition of the primer is instantaneous so I don't think it matters much for plinking and practice.

tightgroup tiger said:

I certainly don't loose any sleep wondering if I missed any.

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I wont loose any sleep over it either.

LiveLife said:

Or simply drill out small flash holes to match other "normal" flash holes.

One more thing to check when sorting 9mm brass:

• Steel/aluminum cases
• Brass plated steel cases
• Cases with internal step sleeve
• A-Merc and other headstamp with known QC issues (Inconsistent case wall thickness and/or thicker case wall brass)
• S&B, RWS and other headstamp with tighter primer pockets
• Norma brass to drill out flash holes

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Another is Win NT cases. I haven't bothered checking, but I think those use an entirely different sized primer.

gunzby said:

Another is Win NT cases. I haven't bothered checking, but I think those use an entirely different sized primer.

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These deserve something more powerful. More like det cord...

CQB45ACP said:

AKA, wag the dog

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I had a friend shooting some Norma brass on Sunday. When trying to deprime the brass with my Lee 9mm sizing die the pin was too large and would just get pushed up and not touch the primer. If I wanted to reload with these I'd have make the hole bigger. I have piles of 9mm brass so I'm not going to worry about it, but if I was just starting out with minimal brass I'd find a drill bit that worked and do it.

I have seen 'small' (smaller?) flash holes most on European made brass. S&B comes to mind, but the factory loadings work fine.
Yes, I have had decapping pins stuck in flash holes to the point they detach from the decapping and neck sizer rod. I was surprised as that same bit of equipment worked quite well for other cases and didn't get stuck.
My solution is to use a flash hole uniformer and de-burring tool. No, it will not oversize the flash hole.

However, part of the problem is one usually doesn't notice this UNTIL the case has been initially fired and the decapper stuck. One can simply retire the suspect cases. Unless it's something exotic like a .373 Umpah-Whoopee Express case. Perhaps a 'special' decapper pin for those 'special' cases.

In this time of 'shortage', one must decide which to keep and which to pitch. There is a (relatively) simple way of overcoming.

gunzby said:

Another is Win NT cases. I haven't bothered checking, but I think those use an entirely different sized primer.

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Winchester NT and other non-toxic cases use "Non-Toxic" primers without heavy metals and cleaner burning but SIZED THE SAME as regular primers.

They do have LARGER flash holes.

Rule3 said:

What is a normal hole?

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I don't think there is a NORMAL flash hole size. Manufactures make them what ever size fits there needs. I have found brass with huge holes & ones that my depriming pin won't go through. The best we can do is make them all the same if we want a round to be a consistent shooter.

AK Hunter said:

I don't think there is a NORMAL flash hole size. Manufactures make them what ever size fits there needs. I have found brass with huge holes & ones that my depriming pin won't go through.

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Yes.

While SAAMI does not publish "standard" for flash hole size/diameter (See page 26 for primer pocket/primer standards), difference in flash hole and depriming pin diameters we see may be minute variation in Metric vs English/Standard sizing like how some Metric sized European/Italian/Russian primers are skosh larger than US made primers. (They are good for extending life of older brass with enlarged primer pockets though)

And larger flash holes we are seeing are either non-toxic cases or flash holes enlarged by reloaders.

AK Hunter said:

The best we can do is make them all the same if we want a round to be a consistent shooter.

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Primer "flash" is not an instantaneous event rather "engulfing and growing" primer detonation flash that can vary in flash diameter and length. If you want utmost consistency in powder burn whether powder forward or not (Most semi autos that feed rounds from the magazine are "powder forward" when chambered and with an AIR GAP when not 100% case fill loads ), you may want to uniform the flash hole.

But of course, YMMV.

LiveLife said:

If you want utmost consistency in powder burn

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What percentage of consistency would be obtained by that extra effort? Are we talking 1% or perhaps 5% to 10% to justify adding that step?

RashQuestion said:

What percentage of consistency would be obtained by that extra effort? Are we talking 1% or perhaps 5% to 10% to justify adding that step?

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Good question! Run a few ladders and let us know.

LiveLife said:

Yes.

While SAAMI does not publish "standard" for flash hole size/diameter (See page 26 for primer pocket/primer standards), difference in flash hole and depriming pin diameters we see may be minute variation in Metric vs English/Standard sizing like how some Metric sized European/Italian/Russian primers are skosh larger than US made primers. (They are good for extending life of older brass with enlarged primer pockets though)

And larger flash holes we are seeing are either non-toxic cases or flash holes enlarged by reloaders.


Primer "flash" is not an instantaneous event rather "engulfing and growing" primer detonation flash that can vary in flash diameter and length. If you want utmost consistency in powder burn whether powder forward or not (Most semi autos that feed rounds from the magazine are "powder forward" when chambered and with an AIR GAP when not 100% case fill loads ), you may want to uniform the flash hole.

But of course, YMMV.

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Yup and Yup. One of the reasons I use standard small rifle primers on .357 Mag and Max loads with "rifle" (a.k.a. "magnum handgun"; a.k.a. mid-range) powders is they are designed to give a longer burn versus standard small pistol primers. I tried it once years ago (mid-90's) out of desperation because I ran out of small pistol primers and found they worked as good as if not a little better in heavier (170-200gr) cast bullet loads. It worked well enough to become habit. I also tried using large rifle primers in .44 magnum heavy cast and jacketed loads - and let's just say it wasn't such a success. Nothing wrong, per say, just not worth making a habit. I had to use a large rifle primer pocket uniformer to take about 0.010" out of the bottom of the pocket to keep them from standing proud and they weren't really any better than magnum large pistol primers. In all, I don't recommend large pistol primer pockets fit for large rifle primers but small rifle primers in long, straight cases like the .357Maximum, with slow powders in the H110/W296, 2400, IMR 4227 burn range are a winner.

RashQuestion said:

What percentage of consistency would be obtained by that extra effort? Are we talking 1% or perhaps 5% to 10% to justify adding that step?

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There is no data to support any of this. At all. If I’m wrong, show me.
That is to the extent we’re still talking about small primer holes, irregular primer holes, in 9mm.

AK Hunter said:

I don't think there is a NORMAL flash hole size.

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Sure there is....

Standard holes are .081"
Small holes are .0625"
Norma/Lapua are .059"
.50 Cal BMG is .140"

K+M Precision and Sinclair stock the reamers for the above..
Norma flash holes are smaller than a Redding decapping pin (.061"). But I believe they might sell a smaller pin.
Lapua and Norma have small flash holes for a more controlled ignition.
Their holes are also 'drilled' as opposed to being 'punched out'.

CQB45ACP said:

There is no data to support any of this. At all. If I’m wrong, show me.
That is to the extent we’re still talking about small primer holes, irregular primer holes, in 9mm.

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Where is the data contesting it? Any of it. Show me.

part of my "prep" for range pickup 9mm, 45acp and 380 auto brass is running a .080" dia. drill bit through every flash hole. sometimes i have to get out the vise-grips for more leverage to "drill" through the small flash holes. this is a "one and done" operation and done when i have a couple hundred cases to "prep". ocd? ... maybe

murf

RashQuestion said:

What percentage of consistency would be obtained by that extra effort? Are we talking 1% or perhaps 5% to 10% to justify adding that step?

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There are other reloading variables to factor along with shooting variables so isolating flash hole variance may be hard to tell.

LiveLife said:

There are other reloading variables to factor along with shooting variables so isolating flash hole variance may be hard to tell.

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I completely agree! Especially my shooting variables and for me seeming to practice on the most windy days anyone can find during any given time period.

LiveLife said:

Winchester NT and other non-toxic cases use "Non-Toxic" primers without heavy metals and cleaner burning but SIZED THE SAME as regular primers.

They do have LARGER flash holes.

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Huh

The ones I've tossed I couldn't seat a primer in. Granted I haven't gotten many and didn't bother measuring them