My main match guns are 51 Navies since 2002. I don't use cap guides but I use nipples for No. 11 caps. I have adjusted my powder size from full chamber to 18 gr. This had two results, the caps didn't jam the action and my guns stopped shooting a 6" pattern and closed up to 2"-3" at 25 yards. At one time and only once I put 5 rounds in a three hole clover leaf with the reduced load. Unless you are shooting for money just go shoot them and enjoy the smoke if one jams take the hits and fix it with a grin on your face.
I only use AMPCO nipples that I shortened till a .001 filler gage fits between the hammer face and nipple. I used:
Tuning the Pietta Part 1 & 2 by Larsen E. Pettifogger SASS # 32933L.http://www.hutier.com/Tuning%20the%20Pietta%20Pt1.PDF http://www.hutier.com/Tuning%20the%20Pietta%20Pt2.PDFhttps://gungiveaways.com/tuning-the-...r-competition/
Making a Colt Cap & Ball Work by Utah, SASS #11601https://docplayer.net/53598632-Makin...ass-11601.htmlhttps://gungiveaways.com/making-a-co...revolver-work/
Tuning the Uberti Open Top Revolvers Part 1 - 4 by Larsen E. Pettifogger, SASS #32933Lhttp://capandballrevolvers.com/pdf/G...s_Complete.pdfhttps://gungiveaways.com/tuning-the-...top-revolvers/https://forums.sassnet.com/index.php...omment-3804805