Originally Posted by fj40mojo
That's great if you follow the rules and don't exceed maximum published data-EVER. But if you want to ring all the performance out of your rifle you aren't going to follow all the rules all the time, the Swede has a lot more potential than the reloading manuals would lead you to believe. I shouldn't be pushing 140grn pills at 2850fps, but I am and with out pressure signs. I can go faster yet but this is where I hit the accuracy node and don't have enough case capacity to reach the next node. Ackleyizing the Swede will get you there by reducing bolt thrust and increasing case capacity, I would think that 3100fps would be doable with 140grn bullets.
The 'rules', as you call them, are there so folks don't hurt themselves. I realize published data is what it is out of respect for the '94/'96 Swedish Mausers. If you read the intro in the loading manuels, it says in an action more modern then the Swedish Mausers, more velocity w/stouter loads is possible. Modern made actions and brass make it possible. By Ackley-izing the 6.5 x 55 you may gain 150fps or so. If you need more, you might look at a different cartridge case. Your desired 3100fps. is a max load for the .264 Win. Mag., which a much larger volume. There have been 100s of thousands of Mauser '98s converted to feed and fire the Winchester Magnums, I happen to have a few of my own. Some, like your FN, came from the factory for the Win. Mags. So,to me, there's no question as to their strength. I have
seen more than one, over the years (the last 35 or so) that have set back the locking lug abutments, turning an otherwise fine action to junk. To reach that 3100fps velocity in a case smaller than that the size of a Win.Mag. will drastically increase pressures and I don't think the straight walls of an Ackley case will be enough help in the Mauser. But, before I did it to a 6.5x55, I'd step up to a case with more capacity to try to keep pressures under control. And, by the way, that 2800 to 2850fps. seems to be the velocity range the guys shooting .260's, 6.5x47's and 6.5-284's in competition are at for their best accuracy. You might send it like Captain Kirks' 'phaser' but does it go there accurately? All of this has been tried 20, 30, 40 years ago. If you look around some of the gunsmithing books and on the web I'm sure you can find some pics of catastrophic failures. Floor plates blown out/off & mag boxes swelled, stocks splintered, bolts unremovable from the action because of set back. A well made '98 is a fine action, but not the one I'd want to try to 'hot rod' beyond its capabilities or past the strength of modern made brass cartridge cases.