SIGforum
Sig 239 in .40 S & W convert to 9mm

This topic can be found at:
https://sigforum.com/eve/forums/a/tpc/f/150601935/m/9390078854

July 13, 2019, 09:20 AM
chuck416
Sig 239 in .40 S & W convert to 9mm
I have a Sig 239 that was a police surplus in .40. It is lightly used, has been refinished in two tone brushed nickle and traditional blue crekote finish. I'd like to convert it to 9mm. Is that possible? Thanks.
July 13, 2019, 10:04 AM
Nipper
Yes. A number of us on the SF (including me) have successfully done it. GaryBF was one of the first.

1) Can use a Sig OEM 9mm barrel, unlike most other .40-9mm conversions. No conversion barrel needed, although you could use one.

2) My own P239 .40 to nine "conversion" functions fine with BOTH .40 mags and 9mm mags. Note that the mag well is narrower on the .40 compared to the nine. CORRECTION: Per GaryBF, should read " Note that the mag well is narrower on the nine compared to the .40."

3) Some have changed to 9mm RS, I didn't. Works fine with .40 RS.

4) All my P239 mags have the discontinued Sig "Plus 1" base plates. Function fine with the conversion.

The P239 is somewhat of an anomaly in this regard. If it works...it works.

If the pistol is intended for SD, thoroughly test with your carry loads. Regardless of whether you use a native 9mm barrel or a conversion barrel.

This message has been edited. Last edited by: Nipper,


______________________
An expert is one who knows more and more about less and less until he knows absolutely everything about nothing. --Nicholas Murray Butler
July 13, 2019, 01:04 PM
chuck416
Thank you so much for the input.
However, due to fat thumbs and poor proofreading, I asked the wrong question. Same question different gun.
Can I convert a Sig P229 in .40 S&W, into a 9mm?
Thank you.
July 13, 2019, 01:20 PM
GaryBF
quote:
Note that the mag well is narrower on the .40 compared to the nine.

Nipper, no, it is just the opposite. 9mm magazines are slightly loose in the 40 frame.
July 13, 2019, 01:26 PM
Nipper
Thanks Gary. Same problem as chuck416. Smile

OP, P229 requires a TRUE conversion barrel from Bar-Sto or EFK Fire Dragon. Sometimes the .40 mags will work with 9mm. Try them first. Seems the .40 RS works most of the time. Reliability seems to depend on the specific gun. Coin flip.

https://www.barsto.com/categor...in.cfm?ID=229&cco=68

https://efkfiredragon.com/sig-sauer2.html

Might want to correct the thread title too.


______________________
An expert is one who knows more and more about less and less until he knows absolutely everything about nothing. --Nicholas Murray Butler
July 13, 2019, 01:41 PM
GaryBF
quote:
Can I convert a Sig P229 in .40 S&W, into a 9mm?

Yes, but it is not as easy. Since the P229 uses different locking inserts for the 9mm and 357/40, you must buy a conversion barrel, or find a 9mm locking insert to use with the factory 9mm barrel. As with the P239, the frame are slightly different, so 9mm magazines are loose in the 40 frame, but they work. You can feed 9mm rounds from a 40 magazine or buy P229-1 9mm magazines, which are are slightly wider.
July 13, 2019, 08:03 PM
GP229
The barrel diameter is different on a .40 barrel than a 9mm barrel, so a barrel, slide, and locking insert are required to use OEM parts to convert from .40 to 9mm on a P229 or the barrel will be lose in the slide at the muzzle end.

.40 barrel OD .545"

9mm barrel OD .525"

The answer is to use a conversion barrel.
July 13, 2019, 11:47 PM
sns3guppy
It's not the right way to go, but I have shot 9mm with a stock 9mm barrel in the .40 P229 and P226, using .40 mags. It ran fine, but I wouldn't ever carry that or do any real shooting with it. It was a curiosity, and it worked. I imagine it would lead to increased wear.
August 08, 2019, 06:46 PM
4MUL8R
Inexpensive 40 S&W ammo is available, from police trade-ins. You may find it more advantageous to search for low cost ammo than to convert to 9.


-------
Trying to simplify my life...
November 07, 2019, 03:37 PM
markstempski
quote:
Originally posted by chuck416:
I have a Sig 239 that was a police surplus in .40. It is lightly used, has been refinished in two tone brushed nickle and traditional blue crekote finish. I'd like to convert it to 9mm. Is that possible? Thanks.


Do you reload? Get a stock 357 sig barrel. I have a barsto 9mm barrel for my 229 but seldom use it as have 226 in 9mm. One can reload 357 sig for slightly more than for 9mm once have enough 357 sig brass on hand. I like starline. You can use your 40 cal mags.