[Hellgate]

Roshi,
Take some JB Weld and fill in that little safety notch in the hammer face. A lot of cap jams are due to the fired cap getting grabbed by the hammer notch and pulled off the nipple when the gun is cocked only to be tipped off into the "works" by the frame. With the notch filled in the hammer face is smooth and the cap (even if blown back by heavy loads) tends to get pushed back into the cylinder's nipple cutout to be rotated out of the way when the gun is cocked.

Be sure to thoroughly clean, degrease, and shape the filled notch area with a very slight concavity so the JB doesn't smack directly on the cap. I make a dam out of masking tape, leave the gun pointed up (cocked) held in a padded vise overnight while the JB sets. The next day I remove the excess JB with chisels and a Dremel wire brush. I rarely get cap jams anymore. I only load 5 in my Colts rather than use the safety pins and dislodge the JB Weld.