Hello ,im going to do a long term 500 j build ,i have a excellent condition Columbian FN mauser military action 30-06 or buy a New Mark X action which has magazine and bolt face for 300 win mag .I planning on getting a 6mx mag from Duane Wiebe ,when i get to it .Which is a better choice of action ? i dont want to have to re heat treat the FN [if that was required]Thanks

either would work .. unless you are planning on building a classic, iron sighted only, I would suggest the mark x..

please check with Paz and ShortandFat here on AccRel as they have a 500 AR reamer down in Oz .. uses rigby cases as basics... link in my signature.