12 grns sounds very light in anything bigger than a .36 but what works for one may not work for all.
A small issue with ROA is that when the hammer is lowered from full cock to half cock, it is possible for the bolt to be engaged in the cylinder,the trigger drops into the half cock on the hammer and the hand drops into the next detent. locked up proper.
A remedy is to remove the base pin and jiggle the cylinder untill the bolt is free.
Seen the jam a blade in there and hope it doesn't do to much damage,also heard of strip the action.
My suggestion doesn't cause damage or end the session early.
Good luck and patience.