What causes them to shoot high?

Hello, JBOGGS,
We would need some info about your loads for starters. Bullet type, weight, powder, charge, crimp or not. Not knowing anything else, I would guess that the load is light. Faster loads generally shoot lower. However, if the load is pretty stout, that would not be the cause.
Let us know.
 
Mike

Mike is right, without some standard to start with it's hard to say why it shoots as it does. I would try some factory loads that are of  known weight and velocity to get an idea where the gun is shooting compared to your loads, since you didn't specify what you were using. I do know that a lot of the Ruger shooters have stated that the front sight height on the short barreled guns are a little low and some of them have added height by various methods or had new front blades installed. If you get to that point I'm sure there is someone here who can advise you on corrective measures.  At the risk of losing you to another forum you may want to check out the Ruger forum   to see what you can see from those guys  http://www.rugerforum.com/phpBB/index.php?sid=511fa64c5d96f1d9788741a0f0e65a81      Chris

I was reluctant to list my sample loads for someone might take them and use them in something other than a Ruger.  But I have been shooting groups and trying to figure out what the gun likes.  I have been using a 240 x .429  LSWC, over 6 grns of W231, COL 1.479, with a light crimp.  Also been trying some 240 lswc over 6 grns of Unique, and of course I tried some Skeeter loads 7.5 grn of Unique.  I tried some Titegroup but didn't like it.  I have the sight bottomed out and most of the loads shoot about 1"-3" high at 25 yards off the bench.
 
I am new to Single Actions and thought it might have been something I had not thought of yet.
 
Thanks

It does make sense to review your loads, but in my experience the fastest way to change any kind of point of impact in a Single Action is to change your grip. Because of the nature of the "plowhandle", you can achieve all sorts of different hits.
Also, while you want to hold a SA firmly, you do not want to force your will on it-allowing the gun to rise in recoil is exactly how they are designed. Generally, if you want to bring your shots down, take a higher hold.