Since most of the good loads are lead for the 45-70. If you do not clean the chamber, good scrubbing, the 457's may not chamber. Keep in mind also that the closer the bullet is to the rifling the more accurate the load will be. The extending of the 457 chamber may make shooting 45-70 disappointing. And finally, the Marlin, no matter how you color it, is still a 40000 CUP rifle. The 45-70 Government loaded to "level three" has harvest game all over the world. The increases in performance are minimal at best. Why try to enhance something that already works great.
Robert
