For normal loads (factory equivalent) my Ruger no. 3 likes IMR-4227 and the Speer 45 gr soft point. My Kimber Super America likes the 45 Speer and Olin 680 (discontinued, but I have a couple pounds of it).
For an accurate but slow load, the Ruger no 3 does real well with a 50 gr Speer or Sierra Blitz and 11.5 grs of IMR-4198. IIRC it gives about 2200-2250 fps.
A load that has worked well on squirrels is 9.5 grs of IMR-4227 and the old Speer 55 FMJ (with a somewhat rounded nose profile).
