Good question G Smith-that's why I am using a Tikka 308 action and clip to build the rifle on-the 22-250 action is the same length but the clip of course is plugged to accommodate the shorter cartridge length.I compared one of my old 220 ackley cartridges to the clip for the 308 and it will work( lengthwise perfectly) I feel anyway.I chose the Tikka M55 because I have had such fantastic results with them over the years.THE NEW T3x actions are all the same size from 204 all the way to 338 mag-just block the clips accordingly-not a huge fan of the new T3 compared to the M55 or M65 Tikkas.

My 204 Tikka T3 for example the clip is plugged so you have zero room to play with bullet depth-I like seating closer to or right on the lands-no can do with this gun unless you shoot one at a time.M55 308 Clips will give me room to play with the 220 Ackley bullet depths and hopefully give me hassle free feeding-they are an inline clip.

I'm not familiar with tikka's, wish I could help.

Any coning of the barrel would help if possible and may have to tinker with the feed ramp but where there's a will, there's a way is how I tackle things! Lol

Big Swift fan myself. Have not AI any Swift but my next rebarrel will be a fast twist to shoot heavier bullets.

Love my .22-.243 Middlestead. The cartridge was designed for the longer heavier bullets (longer neck I believe than the standard 22 - 243)

Built mine for lighter bullets. Had a need for speed when I was younger. Now wish it had a faster twist. Would enjoy playing with the heavier 22 cal bullets they have now.

Still one of my baddest bang flops in the safe for coyotes. 50g bal tip at 4240. Nice just to point and pull. still holds my longest coyote kill from a hunting situation.
Coyote made one last pose jut before making the brush on the edge of a hay field. Never will understand why they take that last look. Just recall putting a little sky between the crosshair and his back. Carried the laser with me and shot the truck once I got there. 560 yards. Miss them days. Don't get out enough anymore.

I have a No 1 used to belong to my Dad. He completely shot out the 6mm barrel. Either going to re barrel in the same cartridge or maybe a Swift? still have dies and brass from one I owned years ago.

ML

Rem 700 trued and squared.
Hart barrel
Jewell trigger 16OZ
Mcmillan stock
Everything Robar coated including bolt and internals.

Built by Dan Dowling

MB ,I had a LH 595 Tikka in 223 it had the best trigger I have ever had on any rifle .I sold it recently as it was a TANK to carry, your Mod 55 prolly has the same receiver .I think I would have kept it if the stock fit me better ,it was a sweet shooter .Go ahead with your plans if you enjoy that in spite of what others might say .

Most all my guns people would say, "Why do you want that".