Just to add a little fuel to the fire I did some searching on the Hodgdon web sight for both the 22-250 and the 220 Swift.
I chose the 52Gr. bullet, IMR,Hodgdon,and Winchester powders, selected all powders.
Here is what I came up with.
22-250
Bullet 52Gr HDY. A-Max (Per Hodgdon DATA) Powder Hodgdon CFE Max charge 39.3, FPS 3,932 @63,100 CUP
220 Swift
Bullet 52 Gr. Sierra HPBT (per Hodgdon DATA)Powder IMR4007 42.0 Gr. Max, FPS 3,820 @52,600 CUP
They used 24" barrel for both with 1-14 Twist.
It does seem by this (Hodgdon DATA) that it is possible for the 22-250 to out preform the 220 Swift by a very few FPS in Hodgdon's test for the 52 Gr. bullet.
Went and looked at 4 different manuals for a 52 Gr. bullet and the 220 Swift out performed the 22-250 in all the manuals. Not by a whole lot but by approx 100 FPS / 200 FPS.(the Sierra manual is the only one with the 200 FPS spread)
Now I do have a 22-250 in an OLD Ruger Varminter. One of the better 22-250 I have had.
Never had a 220 Swift, but would love to.
Which one is the best? Well I would say which ever you own.
AS far as a barrel burner between the two it Stands to reason the 220 Swift should be the worst of the two (using the same powder). That is if both were shot the exact same rate of fire .
The swift burns more powder for a slightly longer duration of burn time.
The real variable comes with the shooter and the rate of fire.IMHO
To me having a 220 Swift would be like having a .264 Win. Mag. in a Pre. 64 Model 70 Winchester rifle.
I have a .264 Win. Mag. Pre 64 MOd. 70 Winchester, there are cartridges that out preform the .264Win. Mag. But Me thinks it is the cool factor that makes it for me.