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6/18/2010 2:08:51 PM EDT
Ok question, what or how would one convert 9mm barrel to .357 sig. The bullets are the same size but would have to re-chamber it, I am new to doing this but wondering if at all possible. I already own a Glock 31, so if I wanted a AR that uses pistol ammo thats the way i'd go. I haven't seen any .357 sig set ups for AR.
6/18/2010 2:25:30 PM EDT
[#1]
9mm


357 Sig


bolt face will need to be opened up if you wanna use your 9mm blow back bolt
6/18/2010 3:23:25 PM EDT
[#2]
Didn't think of that just thinking of the chamber its self. Makes sense seeing how that it is a .40 cal casing necked down. Still how can I re-chamber it has anyone done this?
6/18/2010 5:21:21 PM EDT
[#3]
You can always purchase a 40 bolt from RRA if they will sell ya one, then all you
need is a chamber reamer for 357 sig.
You may need a heavy buffer and extra power spring as the sig has a little more
punch than a 9mm.
I went a diferent way with a new barrel I made as it will be DI and it will shoot .357 bullets
instead of .355 that way I can use heavier bullets for subsonic loads.
.

6/18/2010 6:10:28 PM EDT
[#4]
Dumb question but why a 357 sig?  The ammo is EXPENSIVE compared to 9mm or .40.   School me on ballistics....Is this a superior round to the ones mentioned?  

Jeeze I hope a hornets nest was not just opened.
6/18/2010 6:27:12 PM EDT
[#5]
The 357 sig ammo is only cheap if you handload, factory ammo is spendy.
6/18/2010 10:40:21 PM EDT
[#6]
357 sig is so tough to get running in a AR-15 setup that DI is a must.

Blowback 357 sig AR-15 make the case look like 40SW after ejection.

The key is running a 40SW BCG and DI.

Otherwise, you cannot reload those cases.

Would love a DI version.
6/19/2010 11:21:14 AM EDT
[#7]
Quoted:
You can always purchase a 40 bolt from RRA if they will sell ya one, then all you
need is a chamber reamer for 357 sig.
You may need a heavy buffer and extra power spring as the sig has a little more
punch than a 9mm.
I went a diferent way with a new barrel I made as it will be DI and it will shoot .357 bullets
instead of .355 that way I can use heavier bullets for subsonic loads.
.
http://i197.photobucket.com/albums/aa166/redtazdog/AR35calbarrelwshroud22w.jpg
http://i197.photobucket.com/albums/aa166/redtazdog/AR35calbarrelwshroud20w.jpg



............must resist another project............must resist another project..................I have the will power...............must resist...........
6/19/2010 11:25:42 AM EDT
[#8]
Funny but with RRA and their FBI 40SW carbine contract, I really doubt any of us will be able to score any related parts for several months.
6/19/2010 5:23:39 PM EDT
[#9]
Quoted:
You can always purchase a 40 bolt from RRA if they will sell ya one, then all you
need is a chamber reamer for 357 sig.
You may need a heavy buffer and extra power spring as the sig has a little more
punch than a 9mm.
I went a diferent way with a new barrel I made as it will be DI and it will shoot .357 bullets
instead of .355 that way I can use heavier bullets for subsonic loads.
.
http://i197.photobucket.com/albums/aa166/redtazdog/AR35calbarrelwshroud22w.jpg
http://i197.photobucket.com/albums/aa166/redtazdog/AR35calbarrelwshroud20w.jpg



I am doing the same thing, except I am going to try .357 bullets in a standard .355 bore.  7.5" 357 sig carbine, suppressed.  Just need a RR.  I will do a build thread soon.  Parts in the mail.

Damn, that reminds me, need to get the form 1 going.
6/20/2010 4:24:48 PM EDT
[#10]
Well redseacraft if you will read my post I have a Glock 31 wich is .357 sig, and I see 9mm, .40 cal, and all kinds of other pistol rounds for AR and seeing how I already have the ammo if I was going to make a pistol ammo AR i'd do it in .357 sig. I did a lot of research read reports of officers all over the nation and I liked every thing I read about the .357 sig round, and that is why I went with it, at the time the ammo for it and .40 cal were just a couple dollars different.
6/21/2010 4:26:45 AM EDT
[#11]
Quoted:
357 sig is so tough to get running in a AR-15 setup that DI is a must.

Blowback 357 sig AR-15 make the case look like 40SW after ejection.

The key is running a 40SW BCG and DI.

Otherwise, you cannot reload those cases.

Would love a DI version.



The factory sig is expensive. I paid $29 for a box of WWB. Reloading is the way to go here. You must find the right bullets for reloading if you want to stay at factory OAL & keep the bullet in place. Reloading will also benifit with higher velocitys over factory fodder.
6/21/2010 8:36:32 PM EDT
[#12]
I've got a 357 Sig in blow back in the Colt magazine pattern.  Had the bolt and 9mm barrel re chambered by Kurt years ago.  I played with it a few times, but had an issue with  sticking cases.  It's been sitting in storage since then.  Just haven't taken it out to give it a once through.  I don't recall if I was running a heavier buffer with it.

I have everything to reload the 357 Sig, but haven't sat down to reload any.
6/21/2010 9:50:43 PM EDT
[#13]
Reloading 357 sig is slower than 9mm as you have to use spray lube on the case necks.

But it's an awesome round to reload.  Nice slow power and wow do you get some great velocity and a tack driving round.  Very flat shooting.
6/22/2010 4:16:28 AM EDT
[#14]
Quoted:
I've got a 357 Sig in blow back in the Colt magazine pattern.  Had the bolt and 9mm barrel re chambered by Kurt years ago.  I played with it a few times, but had an issue with  sticking cases.  It's been sitting in storage since then.  Just haven't taken it out to give it a once through.  I don't recall if I was running a heavier buffer with it.
I have everything to reload the 357 Sig, but haven't sat down to reload any.


I run mine with the colt style block & CP mags. Function is 100% The ramp required lowering but that was a snap.

I would suspect the gun is opening too early causing the extractor to fail. The sig would require some serious buffer/spring to slow it down & even then the cases will need some serious resizing during reloading.
6/22/2010 4:28:06 AM EDT
[#15]
Quoted:
Reloading 357 sig is slower than 9mm as you have to use spray lube on the case necks.

But it's an awesome round to reload.  Nice slow power and wow do you get some great velocity and a tack driving round.  Very flat shooting.


Yes it is. I lube & size all the sig brass & clean. Then run it through the dillon/lee as usual.

Ran some #s through QL yesturday & found that a 95g FMJ bullet can be pushed to nearly 2400fps from a 16" tube. 1900fps with a 7.5" tube. I also found some 88g Rem 380 bullets. I fear they will shed there cores but you never know until you try
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