Roll Your Own .44



SDMF

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IMO the yaw isn't a speed/twist issue, it's a COG issue. To be taken serious in the accuracy realm, the .40S&W cases would need to be turned down to get rid of the high spots and make the middle the middle (Center of Gravity). More twist and more speed don't really aid a bullet that's spinning off axis and/or isn't balanced. Think tire that's thrown a wheel weight @ highway speed.

Redhawk ROT is 1:20", reported speed is 1050FPS. The bullet is spinning almost 40K RPM, Imbalance in the projectile will reveal itself.

Of course, turning the 40S&W brass down to make it concentric also reduces it's diameter and therefore reduces land-engagement. One would need to see how deeply the brass "jacket" is obturated. Might be damned if you do, damned if you don't. Make them "round" and there's not enough diameter to engage the lands and induce stability. Leave them imbalanced and rotating off-axis and you have the projectile equivalent of a 1050FPS metal weeble-wobble.

#Catch-22
 
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NDSportsman

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Don't by that guys gun when he's done with it. The rifling can't be in great shape after running brass thru it.
 

SDMF

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Don't by that guys gun when he's done with it. The rifling can't be in great shape after running brass thru it.

You think that's worse than all the folks who clean rifles with bronze and/or SS brushes sans a cleaning rod guide?
 

Mr. Stevenson

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Wonder if a resized case would mike less than .429 or if it would improve upon your observations? Thinking on this today: I would skip the bevel and Dremel to 240grn flatnose in the spirit of Garrett's bullets. The stabilization DID improve after the first couple shots.
 


SDMF

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BR shooters take the high spots off of case necks just to even out neck-tension and they don’t even spin. A case that’s been loaded, shot (expanded and sprung back), then hits the ground post-ejection CAN’T be “round” enough to reliably stabilize. IMO the Bullets that did stabilize were luck, not precision. I don’t think sizing would fix any imbalances, it’d take turning the whole case.
 

Mr. Stevenson

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Understood: In context; these are a SHTF solution for a 100yd, eight inch circle pistol/carbine.
 
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Mr. Stevenson

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IMO a .40 and above doesn't need to expand. That's a big hole.
 

Allen

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IMO the yaw isn't a speed/twist issue, it's a COG issue. To be taken serious in the accuracy realm, the .40S&W cases would need to be turned down to get rid of the high spots and make the middle the middle (Center of Gravity). More twist and more speed don't really aid a bullet that's spinning off axis and/or isn't balanced. Think tire that's thrown a wheel weight @ highway speed.

Redhawk ROT is 1:20", reported speed is 1050FPS. The bullet is spinning almost 40K RPM, Imbalance in the projectile will reveal itself.

Of course, turning the 40S&W brass down to make it concentric also reduces it's diameter and therefore reduces land-engagement. One would need to see how deeply the brass "jacket" is obturated. Might be damned if you do, damned if you don't. Make them "round" and there's not enough diameter to engage the lands and induce stability. Leave them imbalanced and rotating off-axis and you have the projectile equivalent of a 1050FPS metal weeble-wobble.

#Catch-22

You know, I consider myself a fairly smart guy, with an interest in shit that goes bang. But DAMNIT, I'm not even sure I'm qualified to read the shit you put on here at times. It's a whole 'nother language...
 

SDMF

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You know, I consider myself a fairly smart guy, with an interest in shit that goes bang. But DAMNIT, I'm not even sure I'm qualified to read the shit you put on here at times. It's a whole 'nother language...

It's just mechanics and vocabulary with some experience sprinkled in.

Hornady used to include a ~15min DVD with their loading manual. IT looked to have been actually made in the late 60's or very early 70's. In that DVD old-man Hornady talked about their processes and how keeping the COG in the actual center of the bullet was of paramount importance. It would then flash to some of-the-era technical animation that showed a bullet spinning on and off axis.

Most short range (100-200yd) Benchrest matches limit the shooters to either .308 cal or .338 cal projectile diameter. They do this because the larger the diameter of the projectile, the easier it is to make it "round". If they let them neck 308's up to .375 they'd need high-speed cameras and some sort of light/laser grid for the bullet to pass through in order to be able to determine the winner as all the groups would be "one-hole". Ever hear someone talk about how well their 375 H&H or some other larger bore diameter rifle shoots? Projectiles with a COG that matches the true centerline axis are easier to make the larger diameter they are.

If the COG of the projectile matches the centerline axis AND the centerline axis of the projectile aligns to travel the actual centerline axis of the rifled bore (rifle or handgun) assuming enough twist and velocity to stabilize the projectile, it'll be reasonably accurate. That has to be "Job 1". Get those 3 things right, you can then run down the rabbit hole chasing 3, decimal place neck tension and all the rest of the tunnels down that deep rabbit hole. Fail to line up the COG/Centerline of the projectile properly, and/or don't get the projectile placed headed down the centerline of the bore there's no need to hop to the rabbit hole, you're just gonna waste a bunch of components and bbl life.
 


Mr. Stevenson

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Musing again: COG might be improved by using cases from one pistol and filling the primer (epoxy/superglue). Which is more important to rifling; length or weight? (Going back to the Dremel/sander concept for perfect 240grn slugs).

- - - Updated - - -

^^^^That's obvious "dumbass". Just curious about any minutia.
 

Allen

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Once again, I just grab my dictionary and try to keep up.

This is why this site, and maybe a couple others, are worth my time. Every...damn...day.



Fugging love it.
 

SDMF

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Musing again: COG might be improved by using cases from one pistol and filling the primer (epoxy/superglue). Which is more important to rifling; length or weight? (Going back to the Dremel/sander concept for perfect 240grn slugs).

- - - Updated - - -

^^^^That's obvious "dumbass". Just curious about any minutia.

https://www.brownells.com/reloading/measuring-tools/concentricity-gauges/index.htm

No need to fill the primer pocket, according to the video the dude left the spent primer in place.
 


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