View Full Version : Converting 229 in .40S&W to 9mm?

Dale Sondgeroth
August 24, 2017, 23:18
About a year ago I bought a Sig 228 parts kit in 9mm, from Copes everything but the frame.

Just bought a Sig 229 in .40S&W. Tried the barrel and slide from the 228 on the 229, it seems the feed ramp on the 9mm barrel is just a little too long, to go all the way on the frame. Thinking about shortening the feed ramp.

Just wondering if anyone has done a similar conversion, and if it worked, or are there other issues to consider?


August 25, 2017, 10:50
The 229 is a sightly wider and beefier gun to handle pressure of 40 Smith cartridge. Otherwise supposed to be same design. The 228 could not hold up to repeated fire of 40 and 357 SIG so they beefed it up some and remonikered it the 229. 228's I believe are discontinued because the 229 can handle all the high pressure rounds and is available in 9mm. 228 has a stamped carbon frame and 229 has a machined stainless frame. I can't say if your idea can be achieved without modifying frame thus making it unsafe to reverse. If can just modify ramp on barrel and make it work then go for it. If have to modify frame would caution against that. Magazines are 100% interchangeable so your barrel fit and proper spring weight may be only issues. Just please don't mess it up, I prefer 40 to 9mm every day of the week and twice on Sunday. Have 9mm SIG's and 40's. Carry a 40 most days and the 9mm's live in vault but have one in briefcase with Osprey suppressor and 147 grain subsonic heavies.

August 25, 2017, 11:06
Sig or mecgar makes 2 types of magazines for the p229 platform, the 40sw / 357Sig mag and the 9mm mag.

The p229 frame chambered in 40sw or 357Sig will not accept the p229 9mm magazine as the p229 40sw / 357Sig magazine and frame narrows down in the last 1.5 - 2 inches (top) of the mag.

Dale Sondgeroth
August 25, 2017, 11:28
Good advice, I also would never mess with the frame.

I have three 9mm. 13 round, 228 magazines that fit the 229 frame, so it should work.


August 25, 2017, 21:19
If not in rush will keep my eyes out for a 228 and maybe work a trade if find as would like a 229 in 40.