# Caliber conversion



## mrmosin (Jan 2, 2007)

I have a USPc in 357 SIG. I know you can swap barrels, 40 S&W, but what about putting in a 9MM? If so, what else needs too be changed?


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## blackice (May 11, 2006)

You can swap between the 357 & the 40 only..... The 9mm barrel is smaller in diameter and will not fit a 40 or 357 barrel..... and the 40/357 slide diameter is to large for the 9mm barrel....

Hope this helps...


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## Knightrider (Dec 31, 2007)

i have the 45 compact, what one can i swap it with? i would rather swap it then buy a whole new one


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## Charlie (May 13, 2006)

By the time you buy a good barrel, change the springs, and maybe have to NOT rely on the extractor (if it's a different caliber), you can almost have another gun. I've put off buying a .22 conversion for my larger caliber 1911's only because with a little more money, I can have a .22 pistol! More guns is better. :smt023


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## Mike Barham (Mar 30, 2006)

Charlie said:


> I've put off buying a .22 conversion for my larger caliber 1911's only because with a little more money, I can have a .22 pistol! More guns is better. :smt023


I think there's something to be said for sub-caliber practice with a gun that totally replicates your defense gun's grip, trigger, and ideally, sights. If I had it to do over, I'd definitely get an Advantage Arms .22 conversion for my Glock rather than my Buckmark.


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## Spartan (Jan 1, 2007)

From HK's FAQ:

Can I convert my USP .357 compact to 40 and vice versa?
Caliber conversions are not authorized by HK.

Can I convert my USP 45 to 40/9 (Custom Sport)?
Caliber conversions are not authorized by HK.

Just because they're not authorized doesn't mean it's not possible, but I take that as they may know something you don't when trying to do this.


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## thomasward00 (Jan 3, 2008)

When converting from 357 Sig to a 40 is the only thing needed is a 40 barrel?


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## Mike Barham (Mar 30, 2006)

I can't imagine the .45 being convertible to a round with _much_ shorter overall length, like 9mm/.40. I don't see how the gun would function. The .45 has a much greater cycle length than the smaller rounds.

The .357SIG is nothing but a necked down .40S&W. Pop in a barrel. Maybe change recoil springs, but maybe not. Not sure if the same magazines will work.


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## TOF (Sep 7, 2006)

Mike Barham said:


> I think there's something to be said for sub-caliber practice with a gun that totally replicates your defense gun's grip, trigger, and ideally, sights. If I had it to do over, I'd definitely get an Advantage Arms .22 conversion for my Glock rather than my Buckmark.


Two of my shooting partners purchased the conversion for glocks and they have been jam-o-matics from the word go.
Practice with them teaches you bad habits, like bouncing the gun off a tree or rock every 5 minutes.:smt076

I prefer a factory built .22 if I am shooting .22 ammo.

:smt1099


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## Mike Barham (Mar 30, 2006)

TOF said:


> Two of my shooting partners purchased the conversion for glocks and they have been jam-o-matics from the word go.
> Practice with them teaches you bad habits, like bouncing the gun off a tree or rock every 5 minutes.:smt076


Interesting. I'd heard good things about the Advantage Arms conversions, and nothing but bad about the Cieners. Thanks for the info!

A conversion kit would theoretically work well for my personal situation, since my only use for pistols is defense, but the exercise in frustration you're describing makes me like my 9mms even more. :mrgreen:


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## Baldy (Jun 21, 2006)

TOF said:


> Two of my shooting partners purchased the conversion for glocks and they have been jam-o-matics from the word go.
> Practice with them teaches you bad habits, like bouncing the gun off a tree or rock every 5 minutes.:smt076
> 
> I prefer a factory built .22 if I am shooting .22 ammo.
> ...


:anim_lol:I know how your friends feel as I almost threw my .40ve in the river after a couple of rounds to the range.:smt1099
:anim_lol::anim_lol:


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