Chrony of Truth

The place to discuss ammunition, reloading, ballistics, loads, and chamberings.
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Netpackrat
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Re: Chrony of Truth

Post by Netpackrat »

More grist for the mill...

7.62x25 85gr WWB
CZ-52
1547 fps, average of 9 shots

12 GA 3" Remington "Slugger" 1oz.
Saiga 12, 19" barrel
1588 fps, average of 4 shots (fifth shot didn't register)

.380 Automatic, 90gr Federal Hydra-Shok
Sig P230
950fps, average of 10 shots

10mm Automatic, 180gr Federal American Eagle FMJ
Glock 29 (stock barrel)
979fps, average of 10 shots
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HTRN
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Re: Chrony of Truth

Post by HTRN »

CByrneIV wrote:Unless they state otherwise, factory handgun ammunition is testfired from a 5" test barrel fixture(they are sometimes bolt actions, sometimes falling or rolling block actions; but always strong rigid single shots)
They're called "Universal Receivers". HS Precision makes barrels for them.
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Denis
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Re: Chrony of Truth

Post by Denis »

HTRN wrote:They're called "Universal Receivers". HS Precision makes barrels for them.
Fascinating, but does Lon Horiuchi endorse them?
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Netpackrat
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Re: Chrony of Truth

Post by Netpackrat »

CByrneIV wrote:
Netpackrat wrote: 10mm Automatic, 180gr Federal American Eagle FMJ
Glock 29 (stock barrel)
979fps, average of 10 shots
Wow... that's fucking horrible.

Even from a 3.8" barrel, that's utter shite.

That means from a 5" conventionally rifled barrel it's MAYBE 1050fps (you get an extra 25-50fps from the polygonal rifling, then 35-75fps fpr the length difference), probably less.

That's .40s&w territory.
Yeah. When they call it 10mm Lite, they aren't kidding. Sad thing is, while I bought that ammo for around $15/50 prior to the Obamalypse, it's probably going for $35-$40 a box locally these days.

Among other interesting things I discovered today, I found that my 10mm XTP loads lost about 70fps when switching from Winchester to Starline brass. Same powder charge, seating depth, same bullet and everything. Just different brass, new unfired in each instance. And also, I'm going to back off on my .380 cast handloads a bit. Using data straight out of one of my books, I've got a 102 grain LRN averaging 1062 out of the Sig. I loaded them up prior to having a chrony, and prior to buying the Kel-Tec. I put one magazine of them through the P3AT last year, and said fuck that shit, went back to the factory loads. Wouldn't be so bad, but I've got another 500 or so of them loaded up.
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Netpackrat
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Re: Chrony of Truth

Post by Netpackrat »

CByrneIV wrote:
Netpackrat wrote: Among other interesting things I discovered today, I found that my 10mm XTP loads lost about 70fps when switching from Winchester to Starline brass. Same powder charge, seating depth, same bullet and everything. Just different brass, new unfired in each instance.
They both large primer, and are you using large pistol, or large pistol magnum? That's a bit more than I'd expect from a different casehead and wall thickness. I've seen 25fps between two different cases in a pistol, but never 70... that's really, kinda huge.

If the case wall thickness is more than a couple thou difference, it may be that your crimp is holding much tighter on the Winchester.
Same CCI large pistol primer, no magnums. 10.0 grains 800X driving a 180gr XTP. I got 1230 out of the Winchester cased loads when I tested them a while back. And now that you mention it, I'm not really happy with the crimp die in the Dillon die set I am using, and bought a Lee crimp die after I loaded this latest batch up. Still, I wouldn't expect to see a pressure loss like that. I readjusted the die before loading the Starline but the amount of crimp should have been about the same. Certainly not enough to explain that sort of difference, or so I would think. Requires more investigation.
And also, I'm going to back off on my .380 cast handloads a bit. Using data straight out of one of my books, I've got a 102 grain LRN averaging 1062 out of the Sig. I loaded them up prior to having a chrony, and prior to buying the Kel-Tec. I put one magazine of them through the P3AT last year, and said fuck that shit, went back to the factory loads. Wouldn't be so bad, but I've got another 500 or so of them loaded up.
Yeah... 1062 from cast lead 102gr? I'd imagine that's significantly overpressure and if you shot it in a lighter slide straight blowback gun you'd be in trouble. As it is, I don't think I'd reload those cases.
Guess it's time to start pulling them. %$(*$%*(&($%$%&*(%$(&*$%#&*( I'll have to go through my books and see where I got that data from.
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Combat Controller
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Re: Chrony of Truth

Post by Combat Controller »

That 10mm is really poking along isn't it? I use mostly Starline and I only load the really hot stuff in unfired cases. I do have a bit of Winchester though, from all the silvertips I've fired. Still, I get better than that.... :o
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Netpackrat
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Re: Chrony of Truth

Post by Netpackrat »

I guess the real question, is whether the loads in the Starline brass were weaker than I should have expected, or if there was something wrong with the loads I assembled in the Winchester brass? I bought the Starline because it was cheaper, but I'm trying to decide if I should relegate it to practice loads and buy a bunch more Winchester brass. After testing the first batch in the Win cases I loaded up a bunch more, so perhaps I should run a few more of them across the chrony first, since they were a different batch loaded at a different time. Dunno. Without having some means of actually measuring chamber pressure the Chrony doesn't necessarily tell the whole story.
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Combat Controller
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Re: Chrony of Truth

Post by Combat Controller »

Sometimes you just get the wrong combo of something. Try upping the recipe by a tenth and checking your crimp and seating depth.
Winner of the prestigious Автомат Калашникова образца 1947 года award for excellence in rural travel.
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blackeagle603
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Re: Chrony of Truth

Post by blackeagle603 »

Yeah, I would be inclined to keep working to find a recipe with Starline brass you like. That'd be a hard one (supplier) to take off my list.
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blackeagle603
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Re: Chrony of Truth

Post by blackeagle603 »

Tight primer pockets require more attention when seating in virgin Starline brass on the LNL-AP. Other than that -- tight primer pockets are a feature, not a bug.
"The Guncounter: More fun than a barrel of tattooed knife-fighting chain-smoking monkey butlers with drinking problems and excessive gambling debts!"

"The right of the citizens to keep and bear arms has justly been considered, as the palladium of the liberties of a republic;" Justice Story
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