I see the often repeated allegation that the L-frames were made to replace the K-frames because of some "weakness" in the K-frames when shooting magnum rounds.
I've just never seen it in real life. I have a 66-2 with over 25,000 rounds through it. 4000 of those were the dreaded 125 grain 357. Its as tight as a tick.
I did have a 686-3 go out of time and it only shot 38's during its time with me. After the repair I dumped it.
Funny how the K-frame magnums continued to be made right alongside the L-frames for twenty five years.
Some "weak" gun, huh.