Hope that got your attention.
I did read the FAQ on the twist rates of the handi barrels.(thank you)
What was missing is the twist rate of the .22-250.
Another twist to ponder is my .30-30 which was purchased new in 92, and it has (I repeat Has) a 1-12 twist, which I believe is better in the .308 bore.
As far as bottoming out your screw, I'm referring to the lug screw.
Purchase a too-long lug screw and grind it down so that it snugs the fore-end to the O-Ring when the screw is bottomed out. It should be the same pressure every time unless you change O-ring sizes. This eliminates the need for precise torque setting on the lug screw for the real anal Handi-shooters; However An aging O-ring or cold one might change the affects of the pressure on the lug over time. It is a good practice to change the O-ring with the same size one periodically.
In memory of Mountain Man, "That's my 2 cents"