A guy I know said he has a 243 Rockchucker.Who knows about this round? Can you fire it out of a 243 Winchester?Thanks in advance.

It is the 257 Roberts necked down with a 32 degree shoulder. the same performance as the 243WCF and the 6MM remington.
One of the best long range ctgs around is the 6.5x284. Many of the NRA 1000 yard shooters use it.

ballisticly, it's a 6 rem... it's a necked down 7x57, tight shoulder, great round.

Like the 6mm, it's a tad more than a 243.. but just a tad.

jeffe