I cast and loaded up some Lee 124g tumble lube round nose bullets, in cases unsorted by head stamp, with 4.1 grains of Bullseye, to OAL varying between 1.12 -1.145. All bullets lubed with Lee Liquid Alox. The loads function fine, but give horrible accuracy, tumbling into target at 10 yards, and cause very bad leading. The BHN of the alloy is about 8. I am thinking I have done several things wrong. Too much powder is causing soft bullet to strip right over the rifling. Too soft of a bullet is causing bad leading. Varying OAL is not good, but should not cause bullet tumbling. Groups ran about 14 " at 10 yards. Factory FMJ loads shoot fine from the gun, a CZ 75BD. Any advice is appreciated.