I've used IMR4831 and IMR4350 in the 300 for years with good results but I tried the IMR4064 and got much better accuracy with less recoil. But this is a mute point now as this rifle is sitting on the used gun rack at my local gun shop. Among other rifle chamberings, I have a .30-06 and a 325 WSM so I didn't need the 300 anymore. If any of you want these 50 cases of W-W once fired brass, send me a pm and I'll send them to you for $5 plus actual shipping.