If I were to order a MRC PH action to build a 500 A2 is the .604 bolt face the correct size or should I start with the .534 bolt face and have it opened? The way I understand it is the .604 is a Rigby bolt face but the A2 is a little smaller. I have searched this topic and found where guys have rebarreled 416 Ribys to 500 A2 in the past but if I am starting with a new action what is my best course of action?

Thanks.

you need the rigby boltface but also the extractor modified to a .500a2 cartridge. Otherwise big problems. Make sure MRC knows this upfront. Make sure they suply exactly what you need.-rob

.590 is the actual on the rigby case, slightly smaller on the weatherby case, due to rebate,,,

then what rob said... extractor must be right
jeffe

Would the same extractor work to the 500 Jeff? If I ended up going with a Rigby based cartridge could that extractor be modified to work or would it have to changed back to a Rigby extractor? My problem is I am wanting to order something and have the most options I can off one action. Maybe I am wanting something that can't be done.

Talk to MRC and tell them exactly the cartridge you plan to use. They were very helpful when I spoke with them a few weeks ago. FYI the Weatherby is a little smaller than the Rigby bolt face. I was in your boat and was going to punt and get the .534 boltface however, they wanted me to commit. So I sort of punted and went with the 416 Weatherby which give me any WB ie 416,460,500A2 or I could open it up further and go with 416rigby,450rigby or larger.

Brad