Tiny flash holes...

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Not 9x19, but igman 223 has flash holes smaller than my depriming pin, and frequently off center. Lost too many priming pins (Lee universal deprimer) in those things, so any that show up in my range brass now go straight to recycle bin.

Igman headstamp is "IK" or, in this last batch, "IK 21"
 
Otto said:
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'.
Click to expand...
Data! Hurray! Where does it come from and is it for 9mm or everything?
Now, does this source say why?
 
GeoDudeFlorida said:
Where is the data contesting it? Any of it. Show me.
Click to expand...
Excellent point, but I asked first (well second actually) way back with comment 10 or so. Comment 8 by @Rule3 was the first.

I simply want some data to support that flash hole size has anything to do with performance in 9mm. Would make things more consistent was the original thesis.

‘cause I’m telling you, I don’t mind spending more time getting to know my cases by first name (as I think you artfully put it) if there is some return.
 
jmorris said:
I have come across brands that are so small they will grab onto the OD of the decapping pin. Will pull the pin out of some dies, that would get old really quick.

There are also some out there with giant flash holes, different even within the same manufacturer sometimes….

View attachment 1026700
Click to expand...
So there is some data…could interfere with decapping. I’ve never had it happen with my Lee nor Redding due to small hole size, but several others here apparently have. But still no performance relationship that we know of.
 
CQB45ACP said:
But still no performance relationship that we know of.
Click to expand...

Performance wise, I doubt there would be a lot of difference but I have never tested any side by side.

It’s been almost 20 years ago now but when I tested the large/small flash hole 45 ACP brass, the larger flash hole gave slightly lower ES/SD but I only tested with one powder/charge weight and the sample size wasn’t very large. Close enough to the same that I felt there was no need to sort them from one another.

Same goes for SP pocket 45 ACP, no need to change the load but do need to be separated due to the mechanical issues of trying to put a large primer into a small pocket.
 
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jmorris said:
Performance wise, I doubt there would be a lot of difference but I have never tested any side by side.

It’s been almost 20 years ago now but when I tested the large/small flash hole 45 ACP brass, the larger flash hole gave slightly lower ES/SD but I only tested with one powder/charge weight and the sample size wasn’t very large. Close enough to the same that I felt there was no need to sort them from one another.

Same goes for SP pocket 45 ACP, no need to change the load but to need to be separated due to the mechanical issues of trying to put a large primer into a small pocket.
Click to expand...
Hey thanks.
 
CQB45ACP said:
So there is no data ... I simply want some data to support that flash hole size has anything to do with performance in 9mm. Would make things more consistent was the original thesis
Click to expand...
I can do a myth busting thread on this if you like.

Just had my first cataract surgery done on my left eye yesterday with Vivity multifocal IOL with 100% light transmission and things are looking good (literally). Surgery on my right eye is in 3 weeks so I may get a chance before or after but I have following myth busting/testing threads planned:
 
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LiveLife said:
I can do a myth busting thread on this.

Just had my first cataract surgery done on my left eye yesterday with Vivity multifocal IOL with 100% light transmission and things are looking good (literally). Surgery on my right eye is in 3 weeks so I may get a chance before or after but I have following myth busting/testing threads planned:
Click to expand...
Good grief man, that’s painful. All I was asking about were performance issues related to OPs 9mm question.
 
CQB45ACP said:
Good grief man, that’s painful.
Click to expand...
Actually no pain. But I am definitely "seeing the light". :D

CQB45ACP said:
All I was asking about were performance issues related to OPs 9mm question.
Click to expand...
No issues. I like doing myth busting threads for retirement. Besides, what else am I going to do in retirement other than build wife chicken houses and pick up cute puppies (Puppy #4 this year) while buying more gun stuff?

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CQB45ACP said:
Excellent point, but I asked first (well second actually) way back with comment 10 or so. Comment 8 by @Rule3 was the first.

I simply want some data to support that flash hole size has anything to do with performance in 9mm. Would make things more consistent was the original thesis.

‘cause I’m telling you, I don’t mind spending more time getting to know my cases by first name (as I think you artfully put it) if there is some return.
Click to expand...
Let us know how your testing turns out. And don’t forget to document your data. :thumbup:
 
tightgroup tiger said:
I just fix them with this. I bought it from Midway USA I believe, a long time ago.
View attachment 1026668
Click to expand...

I use a similar tool of a different make
on brass I've not loaded. For those who
never used one, it goes inside and
cuts any burrs where the flash hole
was punched. One time deal
There's more slivers hanging from a
case than you might think
20210918_171831.jpg
 
CQB45ACP said:
I’ve outsourced it.

And in the interim I’ve drilled out, chamfered, and just generally deburred the flash holes of 100ish 45ACP. Seriously. (And soon my shooting will be much improved.)
Click to expand...
Sorry I responded to the wrong post. That was for @LiveLife re: his next myth busting episode. That’s what I get for trying to multitask.
 
Otto said:
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'.
Click to expand...
What’s the source of this data? Anyone? Buehler?
 
CQB45ACP said:
What’s the source of this data? Anyone? Buehler?
Click to expand...

Well that was a fun rabbit hole.

In the product Q&A Brownells gives the primer flash hole reamer diameter for small rifle primers as 0.0625" and large rifle primers as 0.081".
https://www.brownells.com/reloading...e=48&msclkid=a9b6b4c174481bd02981d591e0dca016

An article in accurate shooter cites the Norma & Lapua flash holes as "The standard dimension for Lapua 220 Russian and 6mmBR flash holes is 1.5mm or .0590″."
http://bulletin.accurateshooter.com/tag/flash-hole/

I'm surprised flash hole data seems to be the only measurement not provided in SAAMI/ANSI Z299.4 (centerfire pistol & revolver ammo) or 299.5 (centerfire rifle). But there is an Army Lab report on the effect of a smaller "spit-hole" (flash hole) on M80 7.62 NATO ammunition. Mil-spec flash hole diameter is given as 0.078". Good info on overall effect of smaller hole.
https://apps.dtic.mil/dtic/tr/fulltext/u2/a599210.pdf
 
Ray P said:
Well that was a fun rabbit hole.

In the product Q&A Brownells gives the primer flash hole reamer diameter for small rifle primers as 0.0625" and large rifle primers as 0.081".
https://www.brownells.com/reloading...e=48&msclkid=a9b6b4c174481bd02981d591e0dca016

An article in accurate shooter cites the Norma & Lapua flash holes as "The standard dimension for Lapua 220 Russian and 6mmBR flash holes is 1.5mm or .0590″."
http://bulletin.accurateshooter.com/tag/flash-hole/

I'm surprised flash hole data seems to be the only measurement not provided in SAAMI/ANSI Z299.4 (centerfire pistol & revolver ammo) or 299.5 (centerfire rifle). But there is an Army Lab report on the effect of a smaller "spit-hole" (flash hole) on M80 7.62 NATO ammunition. Mil-spec flash hole diameter is given as 0.078". Good info on overall effect of smaller hole.
https://apps.dtic.mil/dtic/tr/fulltext/u2/a599210.pdf
Click to expand...
Thanks

Since this thread was originally about 9mm (and maybe 45acp) cases, some of this isn’t germane WRT sizing but thanks much regardless.

I don’t know that I’ve ever seen a Norma 9mm pistol case so I’m not sure that’s germane either.

But you’re correct it is interesting regardless.
 
CQB45ACP said:
Thanks

Since this thread was originally about 9mm (and maybe 45acp) cases, some of this isn’t germane WRT sizing but thanks much regardless.

I don’t know that I’ve ever seen a Norma 9mm pistol case so I’m not sure that’s germane either.

But you’re correct it is interesting regardless.
Click to expand...

What I found interesting is that the SAAMI spec for centerfire pistol cartridges was absolutely silent on the subject. It's been a few years since I've had free (paid for by someone else) access to a mil-spec archive, so I can't check the mil spec flash hole diameter for 45 Auto or 9 NATO. But that is where I would go next.
 
Ray P said:
What I found interesting is that the SAAMI spec for centerfire pistol cartridges was absolutely silent on the subject. It's been a few years since I've had free (paid for by someone else) access to a mil-spec archive, so I can't check the mil spec flash hole diameter for 45 Auto or 9 NATO. But that is where I would go next.
Click to expand...
Yeah don’t know that’s in the cards…all I was after was some validation of the statements and assertions earlier in this thread that deburring flash holes and/or drilling out small ones to some random larger size would improve something, heck anything. I’m talking about actual validation. Proof. Seems there is no such proof.

But in the accurate shooter link you provided (thank you again) there is an article from the Army marksmanship team about flash holes.

Much interesting information on the subject (everyone here should read it) and one comment said it all…to paraphrase, if the shooter thinks it helps, it helps.

Now I want an RCBS case prep station.
 
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