Discussion in 'Handloading and Reloading' started by 1976B.L.Johns., Sep 19, 2021.
Igman headstamp is "IK" or, in this last batch, "IK 21"
Perhaps because they had crimped primer pockets?
Data! Hurray! Where does it come from and is it for 9mm or everything?
Now, does this source say why?
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.
So there is no data.
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.
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.
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:
Stock 10/22 and T/CR22 vs match bull barrel group size at 50 yards
Myth busting "real world" 22LR 50 yard KYL challenge (already started) - https://www.thehighroad.org/index.php?threads/myth-busting-“real-world”-22lr-50-yard-challenge.895021/
No "cleaning" vs cleaned to bare metal 22LR barrel accuracy after 1000/3000 rounds - https://www.thehighroad.org/index.php?threads/you-never-clean-a-22-rifle.894731/page-2#post-12052173
Burris FF 6.5-20x50mm focusing at 50 yards for rimfire shooting - https://www.thehighroad.org/index.php?threads/burris-fullfield-e1-6-5-20x-50mm-169-9-shipping.893341/#post-12061424
Rear bag vs rear mono pod
Caldwell Lead Sled vs bipod and rear bag
Advantage Arms 22LR conversion slide for Gen3 Glock22 new reliability feeding with various brand ammunition
Good grief man, that’s painful. All I was asking about were performance issues related to OPs 9mm question.
Actually no pain. But I am definitely "seeing the light".
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?
Thanks for all you contribute here!!!
You are a better man than I. I hope to be more like you when I grow up!!!
Let us know how your testing turns out. And don’t forget to document your data.
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.)
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
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.
What’s the source of this data? Anyone? Buehler?
They weren't crimped as I do remember that. Maybe I'll run across one this week when I load a batch. If I do, I'll measure it.
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".
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″."
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.
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.
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.
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.
Separate names with a comma.