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OhioGlockMan 11-12-2012 09:47

357 Sig barrel in Glock 20 question
I'm looking at getting a 357 sig aftermarket barrel for my Glock 20- the main reason is cheap plinking with bulk 9mm 115 gr bullets driven real fast. The thing is I'm researching reloading the 357 sig and it's my understanding that you can't just use regular 9mm bullets, you need to use a 9mm diameter bullet specifically designed for the short neck of the 357 Sig. Is there truth to this because the 124 gr flatnose bullets for 357 sig profile are too expensive to do what I want. I want to get cheap bulk 115 gr 9mm bullets and shoot them in high volumes driven fast.

_The_Shadow 11-12-2012 10:21

Sad but mostly true...the bullets that have the radius olgive don't get a good enough neck tension to avoid bullet movement or set back. The bullets wit straighter side walls work much better. I will say I started with the LEE die set for the 357SIG and had two issues, first was CCI and Speer casings heve vey small primer flash holes, even the smaller pin had got stuck in the flash hole, broke off. LEE sent a replacement de-primer but new cases I now hand de-prime with homemade pin, then drill out the flash holes to the normal size of other brands. PITA but only needed once.

Second issue was worst, I had run the casings thru the 10mm carbide pass thru die before sizing in the LEE 357SIG set. The LEE dies are steel dies and even with lube the sizer die started galling and mark the cases. Just like the 9x25Dillon, I moved to the Dillon dies because of the 2 carbide sections for sizing. Yes, they are expensive but they work the best for my experience. I was lucky to find my Dillon dies on the used market for a savings over the factory price.

Sizing is critical to fit you chamber properly, no less than -0.002" below the barrel hood as primer strikes can get too light. Too much shoulder set back will lead to shorter case life or seperations. The neck expander and truing is critical to bullet being straight and holding tight. The Dillon die set doesn't come with an expander but I use the LEE expander or my RCBS 9mm expander for this operation. The Dillon set does have a seater die with double ended seater for TC & Round Nose profiles as does the seperate crimp die.

Good luck with your adventure!

_The_Shadow 11-12-2012 10:24

BTW, I do load the ZERO brand of 38Super bullets they are 0.356" - 121 grain JHP's they work well and also various cast bullets in the 120 - 130 grain range.

OhioGlockMan 11-12-2012 11:13

Thanks Shadow, well just what I suspected and I'm dissapointed. You can get the 115 gr 9mm so cheap and they couldda been driven to 1500 fps for light recoil plinking in the Glock 20 platform. Just too bad.

OhioGlockMan 11-12-2012 11:14

and also it seems like way too much hassle to load 357 sig with the extra steps and precautions u need to take, just a shame

_The_Shadow 11-12-2012 11:50

OhioGlockMan, Don't give up on them, you can do it. The Hornady, Montana Gold bullets are also good as are most of the TC shaped FMJ or JHP. I started loading them for 3 reasons, first I had collected an accumulation of 357Sig brass, then not knowing what to expect form the short falls of supplies and I was already commited to the 9x25Dillon which uses the same bullets with both of these rounds, therefore I decided to load the 357SIG.
I liked the challenge of working with the bottle neck cartridges it has actually made me a better handloader overall. Once you work out the details and know what you are looking to do it pays rewards.
Besides it was cool to use 4 different cartridges from the same pistol.
I'm still waiting on my 357SIG barrels to be made for my S&W10xx guns...that will add a unique setup and flexability from those models.

GLOCKG21 12-26-2012 17:50

i'm casting 125 gr. rn tl to try. i should have my barrel tomorrow and my dies on friday.cant wait to try it out!

_The_Shadow 12-26-2012 18:49

Fit and good lube quality will help to keep the leading from building up in the barrel.

TDC20 12-26-2012 21:40


Originally Posted by OhioGlockMan (Post 19623081)
and also it seems like way too much hassle to load 357 sig with the extra steps and precautions u need to take, just a shame

Yeah, sounds like a lot of extra work and hassle to me. I'm sticking with my 40 S&W barrel. I can get 175gr cast lead SWC locally for about $40/500, and there's never any shortage or premium for 40 S&W range brass. And I can load using my standard 40/10mm dies. I'm surprised more people don't go this route for plinking loads. My G20 cycles these just fine, even with the 22lb recoil spring. Run at 1000-1050fps with a standard primer and Bullseye, they smoke a little bit, but they are pretty good out to 25yds for training drills. Plus, I don't really care if I lose a few pieces of short and weak brass at the range.

Another benefit of having the 40 S&W barrel is for ammo shortages. It could be the difference between having a useful, reliable pistol, or a paperweight if you can't get 10mm ammo. There's lots and lots of 40 S&W out there, and plenty of brass and bullets.

OhioGlockMan 12-29-2012 11:11

Ok I got thinking about this issue more and more, it's my understanding that round nose bullets made for the 9mm luger cartridge are designed with the bearing surface such that if you load them in 357 sig brass and the max SAAMI OAL of the 357 sig, the bearing surface will be lower then the neck and wont grip the bullet. OK- but were taking about using an aftermarket 357 barrel in a gun that has a design and magazines designed for the longer 10mm, what if we load the cheapey 115 grain round nose bullets to a longer max OAL then saami sets for 357 sig so the bearing contact will be on the neck of the 357 brass?????? I mean, its going to be shot in a gun thats designed for cartridges of a longer OAL, and magazines that are the same. As long as these tailored reloads are kept away from a dedicated 357 sig gun like the Glock 32, wouldnt this work??

I'm still hoping this will work because I get hte 115 grain FMJ's in bulk so cheap and it would be cool to be pushing them 1500 FPS

dm1906 12-29-2012 12:21

Too much ado about nothing, I think. I've used a bunch of bullets for .357 Sig and 9x25. From all the Barnes offerings in .355", 80 gr. to 125 gr. (125's are loooong at .722", and specified for .357 Sig), to 147 gr. Silvertip bullets. No problems at any time with either, loaded to SAAMI spec. OAL.

GLOCKG21 12-30-2012 10:48

ok.tried the 125gr lead rn. neck is to long to get a crimp on the bullet.what if you use 40 s&w case?it would have a shorter neck so you could get a crimp on the bullet.right?

dm1906 12-30-2012 12:26


Originally Posted by GLOCKG21 (Post 19797480)
ok.tried the 125gr lead rn. neck is to long to get a crimp on the bullet.what if you use 40 s&w case?it would have a shorter neck so you could get a crimp on the bullet.right?

It depends on the cast bullet. If it's a 125 LRN, dedicated to the 9mm Luger, the long ogive will prevent deeper seat and crimping. Try seating it the shortest you can and still engage the case mouth without over-crimping, and check it for magazine fit and chambering. I've done this, but using a G20 magazine and .357 conversion barrel.

Using a .40 case won't be any different. I make my .357S and 9x25 brass from their parent cases, almost exclusively. I have used very few actual factory necked cases. Shortening the neck would result in a worse condition, than a sloppy crimp. Unless the bullet has a cannelure, very little neck tension is a result of the crimp. Shortening the neck will result is less tension.

GLOCKG21 12-30-2012 13:27

thats what i have got.g20 with lone wolf conv. barrel. the max oal dont matter to much as long as it chambers and feeds?

dm1906 12-30-2012 13:50


Originally Posted by GLOCKG21 (Post 19798130)
thats what i have got.g20 with lone wolf conv. barrel. the max oal dont matter to much as long as it chambers and feeds?

Correct, essentially. If you are a lot longer, you may need to adjust the charge a bit. Maybe take advantage of the gained case capacity. How long you can go depends on the chamber throat and leade. Don't seat so long the bullet is against the taper or rifling.

I use some 9mm Luger bullets, 124 gr. SJSP, that have a cannelure that makes them fairly long. No problem with the wide point. They are .355", so I don't know how they'd work out if they were a .356"+ cast. The LRN's I use have a short ogive, unlike the Luger bullets, so they are flexible with the seating depth. I may give them a try, just to see how long they will go.

GLOCKG21 12-30-2012 13:54

made up some rounds with no powder or primmers with 125gr. cast lead rn. aol 1.2170.
fits in the mag good,cycled the rounds 5 times and dont seem to have any i guess i should be ok.i'll load up some rounds with a start load of 8.9grs of aa#7. hope i dont blow up.

GLOCKG21 12-30-2012 14:07

1 Attachment(s)
here is a pic of the dummy round

dm1906 12-30-2012 14:34

That's long! I didn't realize it was a shouldered bullet. It makes it longer, but also allows for a lot of length flexibility with your platform. It wouldn't work in a .357 magazine, though.

As far as the load recipe goes.....
I think I would start a little lower than 8.9 gr. While you are seating longer, the base will be similar to that of a FP or RN bullet of .357 compatible design, perhaps even deeper.

I would recommend no more than the stock RSA, or even lighter (15#). The G21 does well with the stock spring, but the slide is significantly lighter than the G20. If you have live-fire feed issues, try a G21 slide or a 15# spring.

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