Up until this spring I hadn't had any real great success shooting jacketed bullets with my 12" 357 Maximum barrel done by David White. So, I decided to take the plunge and shoot hardened cast leads with a gas check. "OH MY GOODNESS", is all I can say. The two bullets I have shot so far are the 200 RCBS w/gc & 220 LBT w/gc under Winchester 296 & XMP 5744.
As for accuracy at 50 yards, I am able to shoot 3 shots into a 3/4" group with the 205 RCBS and obtain an an average muzzle velocity of 1,880 fps using Win 296. Put this same load into a 20" rifle barrel and you have the ballistic equal to a factory 35 Remington. I know this because I own a Marlin levergun in 35 Remington.
As for the 220 LBT group size at 50 yards averages 1.5" with an average muzzle velocity of 1,750 fps. This same bullet under 16 grains of XMP 5744 will shoot a 1 inch, "ten shot" group at 50 yards with an average muzzle velocity of 1,350 ps. Lets just say I have found my load for knocking over silhouette buffalos at 100 & 200 yards.