Cap jam is a pretty thoroughly discussed problem for which there are multiple answers. The simplest things most anyone can do that will stop 90% of them are:
#1 Don't lighten the hammer spring excessively
#2 Swap out the nipples for ones with smaller flash holes (to prevent blowback of the hammer) using Slix-shot, Butler Creek, or Treso nipples
#3 Shoot lighter rather than max loads
#4 Slightly take the sharp edges off the safety notch on the hammer face to dull the edges so they are not so "grabby".
#5 Completely fill in that little safety notch that grabs spent caps. I actually had someone refer to it as the "Hellgate modification". The Pietta Colts have excessively wide safety notches compared to ASM guns. I use JB Weld but actually welding it flush would be best. I have never been able to get solder to stick to the case hardening on the hammer slot. Maybe some one can educated me on that. I occasionally have to replace the JB Weld because it can get knocked out from shooting.
For the more gunsmithy types I have seen how to install a cap guard shield onto the recoil shield with a narrow slot to allow a narrorwed/reshaped hammer to fit through or to cut a slot into the hammer face and install a peg in the hammer cutout in the frame in front of the nipple. Both modifications prevent the spent cap from moving rearward but require modification of the hammer face. I once had a pistol that had the cap shield on it but caps would drag against it and make for harder cylinder rotation. I've never installed the peg system but I believe it works the best. All I have ever done is described in the first paragraph. I'm sure I have left something out.
Here's a prior discussion from CAS City with more stuff:
https://www.cascity.com/forumhall/index.php?topic=54411.0