U buy a 9mm barrel for a 40 so you can shoot either ammo, IE the 9 mm for much less per box and you shoot a 40 because you can and want to.. U buy the 40 first so you can have either firearm for much less the cost & why would anyone in their right mind want to sell the 40 at such a loss when it is a great short range self defense firearm.. U change these barrels out in a matter of a couple minutes or less and U are defending yourself statistically within 5 yards or much less. I will get the 357 sig barrel for the 40 if S&W eventually makes one as I also have that ammo and I shoot it also in a Glock 40 conversion.

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Painted my Mag release red