Okay, who can fill me in on this one or point me in the right direction?
A friend showed up with his grandfather's bench gun from the 50's, didn't know what he had inherited, and thought the markings meant the brand of dies to use, which he had, marked ".243 RCBS". A quick look found a note on the cartridge in Ackley's book, but I can't remember where else I've seen and have info stashed over the past 35 years. Since we have the dies and Ackey had a few loads, it's mainly a case of reforming the brass and trimming?~Arctic~

Fred Huntington of RCBS developed that line of rounds and he made the dies. I'm sure other gunsmiths chambered for that round also. I had heard this name but not sure if it's the same but was a 243 Rockchucker or 243 Super Rockchucker. You could call Hungington's (RCBS) may get some information.

He also had his own imp. 243Win. with a *30 shoulder.

the rockchucker was built on a 7x57 case and the super rockchucker on a 3006 case Big difference in chamber length - easy to findout

[QUOTE]Originally posted by butchloc:
the rockchucker was built on a 7x57 case and the super rockchucker on a 3006 case Big difference in chamber length - easy to findout[/QUOTE
Your right I should of looked them up the 243 Rockchucker it's on the 257 case at least in my wildcat book haven't found a listing for the super but shows case OAL at 2.240 on the 243rockchucker the 243RCBS case OAL 2.060. The OAL on the 7x57 case is 2.235 so don't think you can blow that case out. The 243 case OAL is 2.045 and when you AI it the case lenght is 2.025.