What can anyone tell me about this cartridge . I've heard two names for it , .243 Super Rock Chucker and 6mm-06 Improved . Are they one and the same ? I have a Model 700 barrel in this cal. with dies .

Well not sure about 243 Super Rock Chucker there was the 243 Rockucker from Fred Huntington (RCBS) off the 257 Roberts case (case length 2.24")
and they did the 243RCBS off the 243 case. You could call Huntington there still in business but not building rifles and they may have some information on the Super Rock Chucker. I did a search and they made a 243 Super Rock Chucker it's not in any of my wildcat books but dies are made of it. Did you get dies for it?

__________________
Semper Fi
Vietnam Vet
VFW

There is a cartridge called the 240 Super "Varminter" (not RockChucker) that is a 30-'06 necked down. I'm about 90% sure that's what you're referring to. The load data for 240 Gibbs or the 240 Weatherby Magnum would be good sources for this wildcat, as their case capacities and working pressures are quite similar. Expect slow-burning powders like 4831SC and RL-22 to give best performance...but don't expect long barrel life!

Send me a PM if you'd like some starting loads

__________________
Ask me about QDMA.