I've not used a .300 mag, but I shot a ton of 125 gr Sierras through my first .30-06. My Dad used to buy bullets direct from Sierra by the pound on his way home from work when they were in Santa Fe Springs - as a truck driver with 3 teenage sons reloading and shooting, it was a neccessity! We found better accuracy and long-range trajectory with the 125s over the 110s available at that time. This was pre- Ballistic Tip/V-Max. A lot of jackrabbits fell (or flew) to those 125 gr Sierras.
