The Remington brass for the 300 Weatherby is just fine. It is good brass and lasts quite a long time.

However, it is thicker than Norma made brass and the pressures are higher with the same loads. I find I have to reduce my loads 1 to 1.5 grains with the Remington headstamped brass compared to Norma.

So, do not hesitate to use Remington brass, just do not mix it with the Norma (Weatherby) cases.