trharder
Have you installed the percussion hammer in your gun before? When you go to install your #11 hammer and nipple there is somewhat of a science to doing that. In most A&H's unless you get everything installed just right shooting #11's can be a problem. The problem being getting consistent ignition from the cap.
Which A&H do you have, one of the ones made in Missouri or the newer models made in Utah? The reason I ask is there were two different hammer springs made for the the guns a very stiff spring and a lighter spring. Both of my A&H'sare the older models from Missouri, other than a little heavyand a little long they were very good ML's.