Re: BIG Ruger Issue
Unless you'd like to dry prefoul, as part of your cleaning, you need to stop cleaning between cold bore test shots. Any oil based cleaner can take 5-8 shots to burn out of a bore. This before a bore can be considered stable in fouling.
I dry prefoul and my 1st cold shot is as good as any of the day -with some guns(not all).
But I can't think of any reason to clean continually. Why did you do this?
If it was to cool the barrel quicker, that's not the same as actual cold bore shooting(where the entire system is allowed to cool).
With cold bore testing, there is a point where the barrel shifts around most while transiting in temps. With probably a dozen guns now that I've cold bore load developed with, ~10min shot rate has produced the very worst in performance. 5min or less has been ok for a few shots. 1/2hr(for small cartridges) to 3hrs(for large cartridges) has been fine for many shots.
So my goal is 1/2moa accuracy at 300yds at a 10min shot rate, given that other shot rates are better.
Any grouping capability is irrelevant to cold bore accuracy.
I've had guns that hot barrel grouped very well, and yet found no potential in them for cold bore use. Well that was not in their design.
As well I've had guns that were very accurate in cold bore, but couldn't produce a hot bore group I'd want anyone to see. That's ok too,, I don't group shoot on game.