I loaded up 20 rounds on Saturday and did a rapid fire test in my Marlin 1895 circa 1978. It has a 22" micro-groove barrel. The loads were: 63gr of FFg Goex (measure by weight), orange juice carton wad, 400gr DD/PRS boolit pan lubed with 50% Beef fat (hamburger grease) 50% Misc Wax, R-P cases, Rem 9 1/2 Magnum primers, moderate crimp. I loaded one round in the chamber and 4 in the magazine tube. Shot the gun empty. Reload as fast as possible (1 in chamber, 4 in mag tube). Repeated until 20 rounds were shot. I squeezed the trigger as soon as the sights were lined up with the target. The target was set at 50 yards. Below is the picture of the target.
Slim