Use Large Rifle primers with any 45-70 load. I use Federal 215 Mag primers with every load for my Sharps Rifle. I shoot mostly Black Powder but have shot some AA 5744 and cast 405's with great results. AA 5744 is a good powder for reduced loads. It does not matter where the powder lays in the case it still lights great and has no change in velocity. It burns a little dirty but it is accurate. If you were using large rifle primers in your loads and the primers did not go off when hit it most likely was a light hit on the primer caused by the action not locking up tight. Sometimes you need to take a look at the lock up of the locking bolts by taking a marking pin and painting them and open and close the action a few times to see if you are getting even contact. Some times when everything is not perfectly fitting and you don't snap the action shut, you only close it, the locking bolts don't go fully where they should be and it will cause the internal hammer block not to drop completely out of the way. When the hammer drops when you pull the trigger it bumps the hammer block just a little and retards the hammer fall just a little and this causes the hammer not to have enough momentum to hit the firing pin hard enough to pop the primer. Your primer will have a dent in it but it was not enough to set it off.
