Personally, the ONI/FBI 4-inch round butt was the best of the K Frame Magnums. It's only drawback was the thin section of barrel shank at the 6 o'clock position which could be damaged with Magnum rounds that had short bullets that did not seal up the B/C gap that extra fraction of a second, often resulting in a crack at that weak 6 o'clock position. Although it was/is much less likely to be a problem with 145 grains and up, the 110 and 125 Magnums were all the rage back in the 70s when the problem seemed to become widespread after the Newhall and other incidents which caused LE to begin to do all training with Magnum carry ammo rather than training with 38s, and reserving Magnums for qualification and carry.

Fortunately, we now have the newest 66/19s with the 2-piece barrel, which are stronger and which have thick steel all the way around the barrel shank. And, the weapons have round butts, making concealment that much easier.

We really do have access to the best guns available these days!