My New Vaquero in .45 LC shot two inches to the left and about the same amount low at 25 yds when new. I corrected this by widening the rear notch to the right, then filing down the front sight and then daubed the filed metal with cold blue. This corrected the problem but did widen the notch, resulting in a 'looser' sight picture.
Ruger can adjust impact points for you by screwing the barrel farther in or out of the frame, thereby moving the front sight blade left or right. It's a job I'd not tackle myself and would trust only to a superb gunsmith or the Ruger factory...
Here's a pic of the widened rear notch on my N. Vaquero. As you can see, it doesn't take much to move the impact point....but be advised, you should shoot the gun a lot with your primary load to determine just how much to file...same with the front sight...(filing it down raises the impact point)...
In practice, it was file a stroke or two, then shoot a cpl groups, then file another stroke or two etc. I'm lucky to have a 25 yd range right out my back door here on the farm, but the job could have been done on a regular range with a small portable vice...one suggestion...mask everything that's blued on the gun with electricians tape...'cause I'll almost guarantee you'll slip at least once with the file...
I regulated this one for my standard load in .45 Colt (8.0 gr of Unique and a 250 gr LSWC)...Regards, Rod