I know in most of the gun stores around me 357 sig ammo is close to non-existent, and when found is more expensive than 40. What I would do is get the .40 and then somewhere down the road buy a 357 barrel. I did this with my Sig226, my barrel was $160 and was suggested to be done that way because if I bought a 357 it would be really hard to find a .40 barrel (more demand) Then its like having 2 guns