Conversion barrel,
the OD is bigger on the 40 so a 9 would just rattle around in the hole, $99 at Midway
https://www.midwayusa.com/product/5...o-9mm-luger-1-in-16-twist-402-stainless-steel
the OD is bigger on the 40 so a 9 would just rattle around in the hole, $99 at Midway
https://www.midwayusa.com/product/5...o-9mm-luger-1-in-16-twist-402-stainless-steel