The Ackley shoulder keeps the brass from stretching and gives a longer service life from it... plus about 100 to 150fps more MV...

As far as a fast twist barrel on a 22.250, I put a 24 inch PAC-NOR stainless steel barrel with a one in 7 twist on a Ruger Short Action.... it will shoot any bullet ya want from 35 to 90 grains...

the previous barrel was a 243, so the action does not have the spacer like they put on their 22.250s... so I can put rounds in the magazine that are seated fairly far out there... along with having the barrel throated to accommodate a round magazine length...

it runs 75 and 80 grain bullets right at 3350 fps....

The bullets look pretty "wicked" or "cool", depending on how ya want to call them...

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