I have been reloading for Swifts for 35 years and have tried lots of different loads. Most of these have shot well enough to make them a favorite load for someone. But I have pretty much now settled on R-15 as my number one .220 Swift powder. 38 grains of the stuff with either a 50 grain Nosler Ballistic Tip or some sort of 52 grain HPBT match bullet just poke them all on one hole if (here it comes!) I do my part. I like IMR 4064 too, but it has been on the back burner as of late.
I also like 43 grains of H-414 with a 40 grain V-max for ground squirrels. Turns them into vapor with any kind of good hit.