I thought the RCBS summit was an accurate press no?
I don't have first hand experience with the Summit, however have extensive experience with the Rockchucker. For me I look at the construction of the press. The Summit looks rugged, however the die (die plate) is not supported on both sides as the Rockchucker is. With that said there's no support on both sides of the die ("C" press) thus the propensity for the die plate to spring is present especially with the longer sided cases like the 300 WinMag and longer cases. There's a lot of resistance sizing in the sides of the case and then pushing the shoulder back when full-length resizing. I'm not saying it won't work, I just feel that the Rockchucker is a better choice because the die plate is not going to spring because the die plate is supported on both sides. If the die can spring the concentricity is compromised due to misalignment. We're all trying to maintain concentricity where case necks are measured, pushed back to remove runout or turned to maintain concentricity. For me the press is the most important piece of equipment in reloading. Others will express that the Forster COAX is a better and more accurate press than the Rockchucker, then you are getting into the Ford vs Chevy argument. Here's a link that might help:
http://bulletin.accurateshooter.com...s-comparison-rock-chucker-vs-co-ax-vs-summit/