I have semi-inherited a BAR chambered for the .300 Win Mag. I only shoot handloads and have been handloading for years. But this will be the first semi-auto that I have ever loaded for. What I am wondering about is the info listed in the various loading manuals. When working up my loads I am wondering if the top loads listed are good for a BAR (I know to start at the low listing and work up from there). With our sue happy society I was thinking things would be fairly conservative. But for function and safety should I stick to a midrange load for my top load? Also for a BAR should I full length resize every time?

The BAR has a very strong action, it utilizes a rotating locking lug much like a bolt action. I have 2 of them, one .338 Win Mag, one .270 Weatherby Mag and have fired hundreds of about every maximum load you can find listed with no problems at all. I wouldn't hesitate to do this, after working up to maximum as you do, of course.

The cartridges will have to be full length re-sized. I use standard RCBS dies, not small base dies, and they have always worked perfectly.

About the only issue I find with the BAR is keeping your port pressures within the parameters of factory-loaded ammunition. Using a powder that is on the slow side for a caliber can result in higher velocities but also creates higher sustained pressures and therefore higher pressures at the gas bleed port. This can result in overstressing the action with excessive gas/pressure in the piston. With a .300 Winchester, I would recommend nothing slower than H4831, but 4350 might be better.