If shooting a double gun, load the right more open barrel with 6s for close shots, and load 3/4 ounce of tungsten #9s in the left full barrel. Work up a load. Bound to kill out to 60 yards. There will be so short of a shot column in the left barrel that nothing can rub metal. You will be amazed at the number of pellets in this load, 272. Will probably go clean through the squirrel.

Winchester Magnum Dove Loads
 

Winchester is making a "Magnum" dove load (a true oxymoron) with 1-1/4 ounce of mixed shot at a blistering 1400 fps. I don't think I'll be shooting anything like this in my vintage guns. But, if you want it, it's out there.
X
X