View Full Version : springfield xd subcompact 357 conversion

03-10-2009, 1:29 PM
Hi Guys,

I am looking at converting a xd sc 40 to a 357 sig. Does anyone know if the barrel from a 4" xd will work in the 3" subcompact? If so, I can order a 4" 357 sig barrel and have it cut down.

Another feature besides the 357 is you can fit 10 357 rounds in the 9 round 40 mazagine. That means a 10+1 sub compact chambered in 357 sig.

Does anyone know if a spring change would be required? Thanks for the help on this.


03-10-2009, 11:35 PM
You say "another feature". What is the other feature of having .357 Sig? Other than the ammo being more expensive.

Instead of spending the $200+ on the barrel and having it cut down, and the extra cost of buying .357 Sig ammo, you could just shoot your .40S&W more, thereby becoming more proficient of a shooter, which makes the argument for that 1 extra round progressively less moot.

03-11-2009, 12:38 AM
How does 1 more round fit in the magazine? Isn't the diameter of the casing the same?

NOTE: that I am asking the question for real, not facetiously stating fact.

03-11-2009, 1:18 AM
How does 1 more round fit in the magazine? Isn't the diameter of the casing the same?

You are correct.

.40S&W and .357SIG magazine capacity is the same.

For example...
.40S&W Glock 22 (15 rounds) = .357SIG Glock 31 (15 rounds)
.40S&W Glock 23 (13 rounds) = .357SIG Glock 32 (13 rounds)
.40S&W Glock 27 (9 rounds) = .357SIG Glock 33 (9 rounds)
.40S&W H&K P2000 (12 rounds) = .357SIG H&K P2000 (12 rounds)
.40S&W H&K P2000SK (9 rounds) = .357SIG H&K P2000SK (9 rounds)
.40S&W SIG P226 (12 rounds) = .357SIG P226 (12 rounds)
.40S&W SIG P229 (12 rounds) = .357SIG P229 (12 rounds)
.40S&W SIG P239 (7 rounds) = .357SIG P239 (7 rounds)
.40S&W SIG P250 (14 rounds) = .357SIG P250 (14 rounds)
.40S&W SIG SP2022 (12 rounds) = .357SIG SP2022 (12 rounds)

03-11-2009, 8:35 AM
I think it has to do with the neck down part of the 357. Not sure exactly why but give it a try. 10 357s in a 9 round xd 40.

The reason I want to convert is I have another 357 sig and I want to standardize...

03-11-2009, 9:21 AM
yea, i'm a much bigger fan of the .357sig as well. I think it sounds like a cool project. I'd post it up on the XDtalk forum.

As for the .40Slow&Weak, I was never a big fan...

03-11-2009, 11:44 AM
Sounds like a cool idea, i wouldnt be surprised if the barrels are slightly different to make the lock up correctly though. Find someone with a 4" and see if it fits.

06-03-2009, 9:23 PM
Ok, I found a barrel solution. It should be here on Friday. Sounds like I might have to do some light fitting to make it work and then color match it to the gun.

357 sig 11 round in a subcompact is gonna be sweet. Now, I need to get the trigger work done via the springfield factory and I will have quite the pistol.

06-03-2009, 9:25 PM
I dont believe the barrel will work in a compact

06-03-2009, 10:50 PM
I still don't get how it would hold one more round. You have any documentation of other people doing that successfully?

I think some mags can be overloaded anyways, depending on the design, right? Are they just overloading them?

06-04-2009, 3:24 AM
this is the specially made barrel for the subcompact.

On the extra round, The 357 sig is just a tad bit smaller on the neck part. Over 9 rounds it adds up to enough room to get another round in.

Same thing on a usp compact 40.

They can hold the factory number in 40 but 1 extra in 357. I do have one 357 mag for the uspc and it can only hold 10 rounds. This is something the manufacturers know about then...

06-05-2009, 8:43 PM
all fitted and color matched. I will be test firing tomorrow. Hope everything holds together... I didn't get a heavier spring, I hope everything works ok.

06-06-2009, 12:15 PM
The gun shoots awesome, for some reason its alot more accurate. the stock barrel has some play while the new one (which I fitted is alot tighter). I am guessing this is why.

Also, the mag theory with one extra round worked perfect when shooting. I am very happy with the results.