I am new to paper patching and so far I haven't found success. I only took it up because I am getting leading with grease groove bullets. My bore is tapered so I am confused as to what dia. bullet I should use. I am shooting a double bbl. rifle and am concerned about a bullet backing out so I am using a tight taper crimp. I found a patch downrange that appeared to be separated at the case mouth position so I think the taper crimp is to blame. I am loading ( for a .450 3-1/4" BPE) fed 215 primer, 120 grs. swiss 1-1/2fg, bee foundation wax, 1/4"+- spg grease cookie, a fiber disc, a wax paper disc and a .451" dia cup base bullet with two wraps of 0.002" vellum, lubed with case sizing lub. Seated just off the lands. Any suggestions?