35 Marlin,
I had great service from Ruger when I explained to them that Wadcutter bullets from my new GP100 hit sideways at 25 yards. They picked up the gun, put on a new barrel and several other parts, returned it, and now wadcutters make round holes at 25 yards. I am pleased.
But that was a "problem" that could be clearly defined and was not likely to be something the shooter was doing.
When I had a similar problem to yours with an SP101 (but in the other direction) I decided it could be simply the way I hold the gun so I didn't bother to call them about it.
I bought that 2" SP101 last fall. It looked, functioned, and measured the way a revolver should. I was delighted with it until I took it to the range and found that for me, it shot well to the right with every load I tried.
I could move the group up and down with bullet weight, but it always hit to the right. Specifically, at 25 yards, the center of the group was completely off the right edge of a standard paper plate.
When I looked very carefully at the barrel, it appeared to be screwed into the frame too much so that the front sight was past top-center (which would result in the group striking to the right (or anyway, that was my guess).
I sold the gun to someone that will use it for ccw and does not plan to use the sights anyway.
A couple of weeks ago I found a used SP101 that again looked, functioned, and measured OK --- but this time, since it was a used gun, I got my retailer to agree that I could bring it back for a refund if it did not hit close to POA.
Anyway, this SP101 hits so close to POA at 25 yards that I shot our local Bullseye Match with it last week and could hold "center" on the target.
I got lucky with the second SP101 and am most pleased!
I would suggest that you have some other experienced shooters try your SP101 and see where it hits for them.
If your SP101 hits 6" left for other shooters, call Ruger and explain the problem. Ruger has excellent customer service and may be willing to examine the gun and perhaps "adjust" your barrel or install another one. It costs nothing to ask.
JMHO