[Alpo]

I picked up a 40 cal fs x change kit and it's very comfortable to shoot.

 

[pblanc]

I have a full-size P320 chambered in .45 ACP and it shoots very nicely. I shot a full-size P320 in .40 S&W and it was excellent as well. I have a P320 compact 9 mm but I have not shot the .40 or .45 in a compact.

 

[sunmoong]

If no budge concern, .45 ACP will be my choice

___________________
S&W M&P22
Sig P320F 9mm
Berreta CX4 Storm 9mm

 

[olbriar]

I've only shot the 320 in 9mm so I'm really not a source. I will say that the smaller the gun the more you will feel the larger round. How much of that effect will be felt in the 320 and if you will find it offensive.. I can't say.
I have a couple of Springfield XDs. One chambered in 9 and the other 45. I can shoot the 9 well but find the 45 I struggle after a few mags to keep tight groups. It isn't offensive to shoot the 45. Actually it's fun. But, I can't help but anticipating that 45 power. I believe it effects my aim a bit.
I carried that 45 for near a year always figuring that if I couldn't get er done with a couple of mags, it didn't really matter where I was aiming with the third.

 

[Lane73]

I love the sig p320 9mm lineup for range, but I personally carry a single stack subcompact .45 XDS and within 5 to 10 yds I can actually get a pretty decent group (6 shots) being drawn from aiwb holster.

While shooting for target accuracy at 25 yds is doable after a mag or 2 like ^ Mr. Olbriar says the "offensive nature" of the .45 acp out of the 3.3" bbl makes groups more like an abstract art pattern and just not as fun as the 9mm p320s, but it sure makes shooting my 1911 in 45 seem like popping off rounds of .22lr lol (of course my scorpion 1911 has always been a smooth shooter)

So, if you want to "try the other extreme" as you say, then find a lgs/shooting range that does rentals and try a subcompact. 45 acp and keep in mind it's not going to be a range gun that you slowly squeeze off rounds for target accuracy at 25 yds, it's intended use as a ccw deployed for close quarters self defense shooting (& hopefully will never needed) practice with that in mind, draw or start from a low ready position and squeeze off rounds in a hastened manner and see how it runs & see how you like it..

If Sig made a slim single stack .45 subcompact CCW I would own one Yesterday, but other brands to look at of course are the XDS (if I had a do over I would get the 4" bbl, instead of the 3.3"), Kahr P, PW, & CW45, & s&w shield .45 or even a glock 36..

Back on to the op topic, as for the concept of caliber exchange kits for your p320
- if you are looking for the most power for a range toy I would consider. 357 sig x-change kit.
(But ammo will Not be cheap!)
- or if you're just interested in changing calibers because of personal / home defense ballistics then you really just need to look at the data of why most police agencies have opted out on the .40 s&w and returned to the 9mm as their duty ammo.
[Advancements in ammo the past several years have really narrowed the margins of one shot stops between 9mm, 40 and 45 ammo based on statistics by police agencies.]

I keep several p320 mags loaded with personal/home defense 9mm ammo in my jic bag and my p320c with light/laser tlr-4 mounted has 17 +p jhp 124g friends in it for any unwelcome visitors and is my go to gun for home defense.

 

[JohnK1987]

Depending on how much you want to broaden your horizons... I would buy a .40 S&W compact caliber x-change kit... then all you need is the Sig OEM .357 SIG compact barrel (just a drop in) to eventually shoot .357 SIG ammo. The .40 S&W mags are the same as the .357 SIG mags (it's engraved on all of the mags as ".40 - .357").

Of course, shoot the calibers first if you can before making any decision!

.

 

[Gibbs]

I am pleased with both the 9mm and the .45 ACP in P320 Compact. The .45 weighs a bit more, and the slide is a bit wider, but not by much. Recoil, I really don't notice it. However, I'm 63 and started out shooting a Ruger Super Blackhawk in .44 Rem. Magnum when I was 18.

I've attached a picture of a target I shot with the .45 slide and fire control group in a full size-cut down to- Carry configuration so I could use the 10 round magazine. Works well, just move the FCU over to that frame and shoot. Most of the time I carry with the Compact grip module, in both the 9mm and the .45 ACP.

031117-45ACP_Full-to-carry

 

[Gibbs]

And this is a target shot with 15 rounds at 21 feet, with the .45 in the Compact module. I placed it on one of my T shirts (that is black) to better illustrate where the 15 round landed "if" it were some criminal element. Of course, this is just theory since the dirt bag probably would not be in the same position after the first round, which, incidentally did go into the small circle I drew.

 

[SMT]

I have a 45 full size and love it. The recoil is more manageable than I thought it would be, which left me wishing I got a carry or compact. Recently got a 357 sig conversion kit in the carry size. Lots of fun lto shoot! Recoil is quite manageable, I think a little milder than a 40.

 

[Gibbs]

I have a 45 full size and love it. The recoil is more manageable than I thought it would be, which left me wishing I got a carry or compact. Recently got a 357 sig conversion kit in the carry size. Lots of fun lto shoot! Recoil is quite manageable, I think a little milder than a 40.

The Compact and Carry are great shooters. I made a "Carry" grip module with Small grip from a "Large" and just cut it off about right. Gives me 10 + 1 in the chamber that way. But, either way, the shooting is not obnoxious, just a bit more than the 9mm which, with it's weight, reminds me of the wife's Bersa Thunder .380. A bit larger bullet but the SIG handles the recoil very nicely.

 

[markbidwell]

Depending on how much you want to broaden your horizons... I would buy a .40 S&W compact caliber x-change kit... then all you need is the Sig OEM .357 SIG compact barrel (just a drop in) to eventually shoot .357 SIG ammo. The .40 S&W mags are the same as the .357 SIG mags (it's engraved on all of the mags as ".40 - .357").

Of course, shoot the calibers first if you can before making any decision!

.

Thanks to all for the great advice! Is it possible to buy the .357 SIG x-change kit and drop in the .40 S&W barrel, i.e. the reverse of what you mentioned?

 

[bumper]

For the price of an exchange kit, you would be well on you way to picking up a nice LEO trade in P229 DA/SA in 40. Arguably one of the best SIGs ever made. Prices range from about $400 to $600 for DA-SA

I'm biased, have 4 P229 40's, two with extra .357 barrels that I never use :c). Here's the most recent ($625 out the door, from a LGS), an '04 nickel - DA 8, SA 3 lbs:

 

[Gibbs]

Or, for 500, one could also get a SIG SP2022 as well, with hammer and decocker but with the rails for lights and such.

 

[markbidwell]

Well. aside from the Sig bug enticing me into the P320, I also got hooked on the P229 Legion (love that trigger) and picked one of those up in 9mm two months ago when it went on sale. I really enjoy that gun too. So, I'm certainly not opposed to the DA/SA hammer/decocker scheme!

 

[SMT]

Thanks to all for the great advice! Is it possible to buy the .357 SIG x-change kit and drop in the .40 S&W barrel, i.e. the reverse of what you mentioned?

Yes, with a 357 Sig, all you need is a barrel to convert it to a 40 (and the other way around).

 

[bumper]

Well. aside from the Sig bug enticing me into the P320, I also got hooked on the P229 Legion (love that trigger) and picked one of those up in 9mm two months ago when it went on sale. I really enjoy that gun too. So, I'm certainly not opposed to the DA/SA hammer/decocker scheme!

If you love the Legion's trigger, you love all of SIG's "Classic DA/SA triggers" as they are fundamentally the same. SIG's listed spec is 10 lbs DA and 4.4 lbs SA for Legions and non-Legions alike. The actual numbers will vary some from gun to gun, as all are production guns, Legions included, little parts are not hand fitted with pride and care by an old guy (like me) with spectacles on his nose. Legions do have a trigger with overtravel stop which enhances trigger feel (and can be easily added to non Legions - as it has been on that "Nickel" above).

I would guess a majority of shooters would be pleased with a stock SIG trigger - compared to many guns on the market today, they are generally good. Still, there will be some glaring exceptions like the little P938 I worked on that pegged my Lyman Digital trigger scale at over 12.5 lbs. (poor fit sear to hammer engagement). So my advice, if a smooth action and superb trigger is what you are after, but what you don't have - "break in" may help some (and you'll hear that advice often - but if what you have is a tur_, after a thousand dry-fires or rounds you'll probably only have given it a polish). Send it to a good gunsmith like Robert Burke.