Hi Homer - I used a 6.5 Rem Mag Carbine (20") for Eastern Ground Hogs (Woodchucks) back in Ontario when I was a kid.
I was driving 100gr. Speer HP's out at about 3,200fps - worked a peach to about 400 yards.

I loaded some 140gr. Sierra Spitzer Boat-tails out at about 2,800fps or a bit more for black bear. I didn't see any and back South in the gophers fields, they opened up the chucks just like the 100gr. HP's. The rifle's 9" twist might have been the reason the bullets were breaking up.

H380 worked well with the lighter, 87gr. bullets too - 57.0gr., if I remember correctly for around 3,450fps and something around 54.0gr. for the 100's.

I had a model 660 Rem., with a 20" bl.