I think that regardless of the sight that you use, the understudy rifle needs to be as close a clone of the primary as is possible and affordable.
I think that a platform like the S&W M&P15-22 would be a much better choice for an understudy of an AR platform rifle than anything else. Even a crappy Mossberg 715 would be a better platform than a mechanically superior Ruger 10/22, but this is just my opinion.
