Do any of you sage folks know the year when Ruger changed the twist rate from 1-9.5" to
1-8" in the No. 1 7x57. No luck on a google search. I just see references to new and old, no dates. Mine was made in 1987 and I am hoping to shoot some 175 grainers. I got a good deal on some old Hornady round nosers. Thanks.

If Ruger won't tell you, call Rody's Gun Shop in Newport (Guild), NH. There is very little related to Ruger long guns that the guys at Rody's don't know. Their telephone # is 603-863-3356 and I think that they are open in the evening on weekdays and all day Saturday.

Jeff

If you want to know whether or not your rifle has the faster twist, why not just measure it?

Well he obviously doesn't know how.
I'd put a firm patch on a jag and rod and push it thru to near the muzzle.
Somewhere where I can get a point in/on the action I'd make a mark showing on the rod that shows "up".

Pull the rod out until the same mark shows back to "up" again. Make another mark and measure between the two. If it measures 8" that's it.
If it's 9.5" Bob's ya Uncle.