The older Clark barrels, and for that matter the barrels of most of the others who made 38 Special 1911s have the ramp integral to the chamber leaving a portion of the case unsupported. No problem till you get a double charge then it blows out the bottome of the case, blows out the magazine and the grip panels. I have seen it happen. Fortunately the owner wasn't hurt, just got a scare and some blackened hands. Newer Clark barrels have a Nowlin/Clark ramp with a corresponding cut in the frame.
I have a 70's era Clark 38 Special Heavy Slide 1911 that had the older style barrel. A couple years ago I had a squib during last shot of the first string of rapid fire. The gun functioned normally except it stove piped that case. I didn't think anything of it and continued with the second string. I actually ended up with 10 on the paper, but two shots were not where I called them. I also ended up with a nice ring in my barrel and the accuracy went to He%#. I sent it back to Clark and they installed a new ramped barrel and charged $450. When they sent it back they had installed a 5# recoil spring. I reinstalled an 8# spring and that seems to work better for me.
I use 2.7 grains of 700X under a Remmington HBWC. I have also used 3.1 grains of 231 and 2.7 grains of Bullseye, all of which give about the same results. I have a frame mounted red dot. I'm a big believer in finding the load that gives the best accuracy in your gun, then tune the gun to work with that load by changing recoil springs. Having said that, I think it's a lot harder to do that with a slide mounted dot on a 38 Special than it is with a 45. The previous owner of my Clark had a slide mounted dot, and he never did get it to function with 100% reliability. He had Clark install their frame bridge.