[Scholly]

I have a real brain bender here. I have a Ruger #1 RSI in 3006 that wont shoot right (grin).

I get very stable horizontal accuracy - less then 1” variation @ 100 yards. The Vertical variation is the problem … I get roughly 4 inches of change in a 5 shot group. It is NOT a steady walk up the paper you would expect from a heat problem. A typical grouping goes one shot an inch high from dead center, the next 2 inches below bulls eye, the next 2 inches above bulls eye and the next dead center bulls eye and the final shot will generally place right on top of one of the first four. Initially, I assumed I had a heat / pressure problem so:

The first “fix” I tried was free floating the barrel – same result
The 2nd “fix” was to glass bed the entire forearm – same result
The third “fix” was to ensure the scope mount’s base did not touch the receiver – same result

I had read the Ruger #1 is sensitive to barrel harmonics so I moved to ammunition; I have tried 150, 165, & 180 grain loads from Remington – same results.
I do a lot of reloading and have achieved good accuracy with other fire arms. So I started with bullet variations ranging from 130 through 200 grain (all 5% below max).

Each load sample size was 10 rounds.
I set up 8 sample loads
I set out 8 targets
I fired one shot from each load at the designated target
I repeated the test twice

Same results!

I have replaced the scope and rings (my wife has a 2nd RSI in 243) Same results - the 243 shoots sub MOA with either scope. I even alternated between the the 243 & 3006 to prove it was not a "biological" failure: 243 5 shot groups stayed at an Inch, 3006 stayed at 4 inches.

These same results occur in 70 degrees as well as 10 degrees (North Dakota shooter here). I have run roughly 300 rounds through this Ruger trying to tune it with no success. I have gone to some pretty extreme measures to correct this with No avail. What am I missing here?!?