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P320 - Project - Suppressed 357sig

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This would fall into the category of the George Mallory quote ... “Because it's there". If you don't know the story behind it, Google it.

My preferred round is the 357sig, but I'm not looking to debate the 'best' round.

I have a SilencerCo Hybrid and love the suppressor. It is insane how quite it is. There is almost zero recoil with a Speer 9mm 147gr round.

When I received my Sig 9mm compact threaded barrel I noticed its pretty much the same size as a full size 9mm barrel. This got me to thinking .... if compact 9mm threaded barrel is just a full size barrel with threading, why couldn't someone thread other full size barrels for use in a compact slide.

I didn't bother asking Sig customer service around this because they will go by the book and say its not supported.

I ordered a full size 357sig barrel from Sig. It came in about a week and a half.

The FS 357sig barrel is, visually, the same as my 9mm threaded barrel. I has already measured my various 9mm, 357sig and 40sw barrels. In those measurements, I found the only difference was the 9mm barrel was .5mm smaller in diameter. Also the 'tab' above the breech face is a hair narrower.

I contacted the dealer here in Denver I used to purchase the Hybrid and ran the plan past him. He partners with a local machinist specializing in gun parts. All of his threading is done via CNC. The threading package also includes a thread protector.

He confirmed the Hybrid could easily handle the pressure of a 357sig (which I already knew).

I dropped off the 357sig barrel, Sig 9mm threaded barrel and my 13x1LH piston. The 9mm barrel and piston are for reference and fitment.

The barrel should be done in a week or two.
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Nice! Hopefully it lowers the sound a reasonable amount; I know it really tests my earmuffs when I run some hot 357SIG loads lol. Probably would be very helpful for saving your ears in a HD situation should you ever end up in that predicament and had to use your handgun.

I have considered loading 158 or 180gr XTP .357 boolits in 357SIG with a bit reduced powder charge (to keep the pressure low with a slightly larger sized projectile) to try and make a nice, hefty subsonic round. I know they make 158 9mm loaded ammo that comes in at about 980fps, but with 357SIG you could get them closer to the 1100fps mark with lower pressures and a heavier boolit than loading a super full 9mm. Probably will order a box of them after the weekend and see how they fly :^)
 

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Are you using a .40/.357S slide? If not, does the fatter .357S case head fit in your 9mm extractor and slide cutout? I just tried to stuff a .40 in my X5 slide and no joy!! Too fat to fit.

Ahh, if it's your "Preffered Round" you probably have a complete .357S setup waiting.
 

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Discussion Starter · #6 ·
Is started with a 320 in 40sw. That allowed me add the drop-in 357sig and the 9mm threaded barrel. If you start with a 9mm you are stuck with 9mm unless you get an x-change kit.

The custom 357sig loafs are a sweet idea but I don't hand load :(

I'm really interested to see how the sound changes. I know that supersonic crack will still be there, but it will be interesting how much the Hybrid absorbs the gasses.
 

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Discussion Starter · #7 ·
Well as luck would have it I'm still waiting for my threaded barrel. The shop has a mechanical issue with one of their machines and is still catching up. I should have my threaded barrel by the end of this week .... or that is what I'm told. We shall see.

Pics and updates will be coming :)

BarSto is now offering threaded barrels, but I'm still glad I went the route I did. The factory barrels meet my needs and I'm still coming in a little cheaper than the BarSto option. BarSto is also not offering the annoying LH threading option. I would love to get a standard thread, but that means I would have to drop more money on a new piston.

I may get a FS 357sig barrel from BarSto, at some point. Having a 5.5in-ish barrel on my FS would so sweet.

https://www.barsto.com/category_main.cfm?ID=320&cco=134

Sig Sauer P320 Ported - Extended .700" and crosscut ported - $275.00

Sig Sauer P320 Threaded - extended .700" and threaded (includes thread protector) - $320.00
 

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Discussion Starter · #8 ·
I got my barrel back today and it looks great. The fit and function in the compact slide is perfect. It should be since its a Sig barrel. Threading is smooth on the piston and thread protector. Now I just have to make some time to get to the range and give it a go.
 

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Discussion Starter · #10 ·
I got to the range last weekend and WOW!!!!!!!!

The threaded 357sig barrel ran great with no suppressor on it. I really didn't notice any difference in recoil. I may have been a hair more accurate, but that could have just been that given day.

The Hybrid treaded on and had solid connection. I ran about 50ish rounds through it and WOW. There were no failures at all. Feed and ejecting was spot on. There was as little blow back of gases, but that is pretty standard for any suppressed pistol. Accuracy was not effected at all. The issue was I hasn't installed the suppressor hight SigLite sights. I was pretty much guessing at my aiming point.

The recoil was almost zero. The gun just popped a little bit. From a sound point, there was no bang from hot gases exiting the barrel. There as a zip from the supersonic round. I was in an indoor range so there no option to try it without ear protection, but everything seemed quite.

Overall I'm extremely happy with everything. I do need to stop being worried about my sight install and just put them on. Was it as quite as shooting subsonic 9mm ... NO, but I knew that going in. It's a super fun setup. Its amazing how much more enjoyable shooting is without the big bang.

The only down side is not I'm looking at the BarSto threaded barrel options including 40sw.
 

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The issue was I hasn't installed the suppressor hight SigLite sights. I was pretty much guessing at my aiming point.
Try shooting with both eyes open with solid sight alignment and sight focus. One eye will center and align your sights and the other eye will superimpose that sight picture on the distant target. Takes some practice and a little squinting to begin with (start at close targets) but once you figure it out, and your eyes to brain adjust, then it is really is quite accurate out to 20+ yards.

If you have a red dot gun you can cover the front of the lens completely so you just see the red dot from the rear (can't see through the sight) and you can shoot it the very same way.
 
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