I have a XD 40 sub-compact with the 3" barrel. Have anyone heard or know if a .357 sig barrel is available for this gun? If not, would be it be possible to purchase a 4" barrel and have it machined down to 3"? I read that in some pistols when using a conversion barrel for 40 to 357 sig you need a stiffer spring. Any info on this with the Springfield pistols? Thanks, Mark
