The 686 in either version will handle any .357 factory load without ANY strength issues. Further, I much prefer the 686 compared to the Model 27/627 because it will handle a wider range of bullet lengths (cylinder is longer than the 27/627). As a for instance, the original Keith 358429 must be crimped over the front band in the Model 27, whereas the 686 can use the crimp groove as the bullet was designed for.

I have a 4" 686 Model CS-1 and a 686-3 with 6" barrel. I have shot them thousands of times with both .38 Special wadcutters and full charge .357's without issue. I have never heard of a 686 having any strength issues. They are great field pieces.

FWIW
Dale53