This is true, you can buy barrels that shoot 9m, and sig 357, that fit it just fine. think 3 guns in one. but again I can not get past the smaller handle. I have my 27, but is no longer my carry. If I need to pull I am wanting a full handful. and I do not conceal carry any more cept as mentioned above.
and cept for the 9m the 40 and the sig 357 are compression rounds.