[Rokman]

I was given a Ruger Blachawk .357 magnum with an extra 9mm cylinder that states on the box that it was hand-fitted from the factory for this revolver. They both have the stated required last three digits of the serial number printed on both cylinders. This was my dad's gun and he said that he never used the other cylinder that he received when it was new. Is this common and is it safe to shoot with 9mm?

[Tom C.]

It is perfectly safe to use with 9mm, but accuracy tends not to be too great due to undersized bullets going down the barrel. .357 mag is .357". 9mm is usually .355", so the bullets are typically a little undersized and may not slug up to groove diameter. Some ammo will shoot better than others, so you may need to try a few to find what works best.

[mikec]

It was a standard cataloged item from Ruger. I don't see Ruger selling anything that isn't safe.

[unspellable]

Rugers sells, or has sold, convertible Blackhawks with two cylinders in a number of caliber combinations. The .357 magnum / 9 mm combination is probably the most common center fire combo. Perfectly safe with any reasonable 9 mm load in the 9 mm cylinder, perhaps not the very best accuracy as there is a long bullet jump and the 9 mm bullet is a tad undersized in the 357 Magnum barrel.

Other Ruger caliber combos include 45 Colt / 45 ACP, 44-40 / 10 mm, and 22 LR / 22 Magnum, although the later is not a Blackhawk.