It came from the factory loaded Winchester 175g Silvertip.
Have you ever chronographed any of this or are you just repeating something you read on the internet?
Last time I ran some Silvertips through a G20 (4.6" bbl) the Oehler gave an average for 5 shots of 1167 fps. Most every factory 41 Mag load except the Remington 210g lead bullet one puts that to shame.
Dave