257 Roberts Seating depth

[MooseHunter]

Building 257 Roberts on Browning Safari Sako. Wondering if I can seat bullets out farther that 2.800 inches. I will modify mag box if it will work. Thinking copper bullets. Hammers etc

 

[SeabeeKen]

I depends on how your barrel is throated. You'll have to measure to find out. I have loaded to 2.9" in my 257AI Mauser action with 90 gr Hammers

 

[LCazador]

Building 257 Roberts on Browning Safari Sako. Wondering if I can seat bullets out farther that 2.800 inches. I will modify mag box if it will work. Thinking copper bullets. Hammers etc

Seat a bullet so the boattail is about even with the neck/shoulder junction then see how it fits magazine and how much you will have to alter mag. Keep in mind monolith bullets can be much longer so rifle barrel twist must be able to stabilize that longer length.

 

[MooseHunter]

I am working with Sako basically a 579. The 90 gr Hammer was on my list. Barrel I am using is 9 twist. According to hammer 10T will work. Wondering how much I should mess with mag box. The gunsmith will figure this out as he will have the reamer and the box in hand. I may send him some dummies seated long and he can adjust COAl/box to reamer.
Does anyone run 62,000 PSI in .257 Roberts these days? Dont see how it would be a problem in modern action but figgered I would ask.