Looking for 35/300 win mag load data. Will be using Nosler 225 grain bullets. Thanks!

Case capacity will be slightly greater than the 358 Norma but if this is chambered in a std length action the bullets would have to be seated quite deep and compromise some of that capacity. If built on a longer action like a Rem 70 that allows OAL to be close to 3.6 inches your useable case capacity will be be greater. I would start with a mid range 358 Norma mag load and work up.Either IMR or H 4350 would be good powders to try

Thank you! Is a Browning BAR concidered a longer action? That's my intended use.

I would suggest the BAR is a std length action. Long action calibres would include calibres such as 300 Wby or 300 H&H 375 H&H etc. Magazine overall length in your BAR will be limited to approx 3.4 inches. Loads for you rifle will be very close to 358 Norma loads