I have the Williams "Ace in the Hole" Sight/rail combo on both my 336s and on my 1894 as well as on my CVA muzzleloader. I have found that its a great combo for some added flexibility. It basically adds a low-pro pic rail on the top for a optics option while having the Williams peep built into the rear of the rail. They are great when you can find them. As you can tell, I am a fan.

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