| Posted: Tue Mar 21st, 2006 03:21 AM |
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1st Post |
caz223
Handloading Master
| Joined: | Sun May 29th, 2005 |
| Location: | Michigan USA |
| Posts: | 448 |
| Photo: | | | Are you a handloader?: | Yes | | Favorite type of cartridge to load?: | pistol | | My favorite chambering is:: | .41 magnum |
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I got to searching around the other day, I tried to improve on the 357SIG by removing some of it's weaknesses.
Bullets for it have too little bearing surface.
The neck on the brass is too short.
If doesn't offer any advantages ofer 9mm with heavy bullets, etc.
So, why not run 10mm brass through the 357SIG sizer, keep the long neck, and load the nice long, 147 grain bullets in them to a usable OAL of, say 1.275-1.285".
I found a few drawbacks, and limitations.
First of all, it would need to be in a gun with a long barrel, to make use of the extra horsepower. At least 5" long. 6" would be perfect.
Second, the magazine would have to reliably dispense the extra long bullets.
The barrel would have to be reamed out to accept the longer neck, and just headspace on the shoulder.
I don't currently have a 357SIG conversion barrel for a G20, which would be perfect.
If anybody has a 357SIG conversion barrel for their Glock 20, (Esp. a KKM 6" barrel.) could you please do me a favor? Could you run a piece of 10mm brass up your 357SIG sizer, and see if the barrel accepts the extra length, or if the barrel would need to be reamed out to have some more freebore.
If the 10mm brass sized to 357SIG flops in your G20 conversion barrel, and lines up flush with the barrel hood, then there's really nothing stopping me from trying it out (except for load data.).
It may require a little trimming, (The mag really can't accept 1.300", which is what I originally wanted in the first place.).
And the 147 grain winchester bullets look goofy loaded under 1.285 or so....
It would be great if there were already a wildcat that would be 10mm length brass, with the shoulder bumped out half way between 357SIG and 9x25.
Sort of a 9x25 with the shoulder bumped back .050-.070", and the case trimmed back just .015 or so... with a COL of 1.275 for reliability in the stock G20 15 round mags.
Shoot, all I'd need is a KKM 6" 357SIG barrel, a reamer or two, a bunch of 10mm starline, and some winchester 147 grain bullets.
Then bust out some powder, and see what's going on....
Last edited on Tue Mar 21st, 2006 03:48 AM by caz223
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| Posted: Tue Mar 21st, 2006 11:43 AM |
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2nd Post |
caz223
Handloading Master
| Joined: | Sun May 29th, 2005 |
| Location: | Michigan USA |
| Posts: | 448 |
| Photo: | | | Are you a handloader?: | Yes | | Favorite type of cartridge to load?: | pistol | | My favorite chambering is:: | .41 magnum |
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The problem is, of course, is that This has already been done, it's called the .357 magnum (Or 10mm, or 9x23, or...). I just wondered if anyone was going to pick up on that. 
I'm trying to do it like a multi-caliber, however.
Let's say (Scientifically, or course,) That I already am going to get the G20 longslide when it comes out. I already have the 10mm-45 conversion barrel and 6" slide.
Now, if I kept the shoulder in the same spot in my 357SIG ammo, and my barrel, and just reamed out the neck of the barrel to have lots of freebore, in the sig barrel, I could have the gun chambered for many uses.
10mm HOT for hunting, having fun at range.
.40 lame for gun games. The extra slide mass would really make it a puss to shoot.
.40 S&W screamers 135 grain noslers at 1500+, for making major at games, I could leave my bloody brass there, and not lose sleep over it.
9x25 just for the heck of it. Already have 357SIG dies, I suspect I can load 9x25 with 357SIG dies by just playing with the die adjustments.
357SIG. Again, the extra slide mass of the 6" G20 would make it a puss to shoot.
357SIG long. Kind of halfway between 9x25 and 357SIG, but it would shoot 147 grain bullets, NOT have any setback issues.
Hopefully the longer engagement with the brass would also make bullet seating a little more precise.
The long neck, the long bullet, and the freebore in the barrel would correct most deficiencies because of the enhanced length, and the bullet would engage the lands earlier than the normal 357SIG. It has enough angle and time in the barrel to align itself to the rifling.
Am I missing any downsides?
Brass life may be shorter. But think, the main downfall of the 9x25 is that the accuracy got compromised when the velocity went too high. This would have a shoulder, a long neck, lots of engagement, and early contact with rifling. Usually the recipe for accuracy in rifles.....
Also, the sig long would be shooting the more accurate 147 grain bullets at velocities considered more normal for the gun, say 1350-1400?
Pressure would need to be raised, but because it's 10mm parent brass, won't setback, is loaded long, and has good chamber support (Aftermarket barrel.), I think 40,000 psi would be fairly safe with the right powders......
OOH found a thread at glocktalk, they have done this before. I guess I gotta find a stock federal arms 357sig barrel, they are engineered to be able to do this.
They're also using longshot, and have found acceptable accuracy and power with 147 grain bullets.
Last edited on Tue Mar 21st, 2006 12:00 PM by caz223
____________________
I'm not just a gun, I'm YOUR gun. (Hold me!)
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