H414 has been my go to powder in the .220 Swift for over 20 years. IMR4064 works very well also but in my experience is slower velocity wise. I ran across a thread here this past summer about a forum member using 4007SSC in his Swift with great velocity and amazing accuracy. Certain lots of 4007 SSC have been recalled but I scored 4 pounds at a local gun shop not affected by the recall and tried some and am very impressed. Velocity is 3993 fps using a 55 Sierra BK jammed .005 and 42.0 grains of 4007 SSC. No pressure signs as well. My rifle sports a 28 inch cryo treated Brux HV barrel and I love it. I do have a load with H414 in this gun and 42.7 grains gets me 4009 fps with very good accuracy. I have had it up to 43.0 and 4046 fps. Start around 42.0 of H414 and work up!
Frank
My favorites have always been 4320 meters better then 4064 ,H380 or 414.do you have any issues with coppering at that speed and barrel length?