[Triggerjerk]

I looked on the Smith web site and the 642 is rated for +p ammo. s rosenthal, the .38 + p is more powerful than the .38 Special, but less powerful than a 9 mm or a .357 magnum. They go up the scale in that order.

I carry a Model 442, which is not +p rated, so I shoot .38 Specials in mine. The weakest load in .38 is the wadcutter, which is a target load. Then there are the standard .38 loads, then the +p's. Buy some of each and see how you both do. Of course, the +p's will hit hardest and have more stopping power.

I confess that I carry the wadcutters in my 442. The gun, like yours, is an airweight, so the lower recoil is fine by me. I am also a bit concerned about overpenetration. Fully jacketed bullets from a .38 can easily shoot through walls and people. So do not carry full metal jacket (or Ball as it is called) ammo.

My 442 is basically the same as your 642, and I love mine. If you find the recoil from +p objectionable, use regular .38's. If that is too stiff, use the wadcutter ammo. Do not carry reloaded ammo in the gun. The target stuff is underpowered, and the other reloads can cause you trouble in court if there is a shooting. Carry factory ammo.

By the way...if you Google Handgun Stopping Power there is a lot of information out there to study. You may also want to browse the magazine stands for gun magazines that have articles you may enjoy.