I have 500 Remington 300 saum new never fired. Come to think of it I also have a NIB Model 7 300 SAUM in stainless synthetic with vias muzzle brake
(included barrrel nut if take off brake) and leupold rings and trigger job. Also RCBS dies and a Forstner Micro seater. You can turn the brass into 7 saum and you just as well buy gun and turn it into a 7 saum. Then you could sell the 300 saum dies to someone else who wants them or just keep them and shoot the 300 barrel out first.