Well Robert, I am sure some will take exception with me, but I have two 220 swifts. One is a custom job on a mauser action, Douglas semi bull barrrel with an old K-10 Weaver when Weaver was tops. I have had that gun 30 years. I never loaded it too hot. That is the reason it still shoots under an inch at a 100yds. My other Swift is a remington 700 classic. That little spit fire will shoot a 52gr. hollow point a mesured 4300ft/sec. It has also shot groups as small as .13 in./100yds That is too hot a load to shoot on a regular basis.
The gun I shoot ground hogs with now is a 6mm in a ruger #1. It shoot 1/4 inch groups with 65gr V-maxs.
With so many new short and supper short mags along with .17 cal, I don't know what caliber has the speed record. But I DO KNOW THAT 220 IS KING