Weaver Vs Picatinney

Any advantage of one over the other? Will a picatinney red dot tube sight fit a weaver rail? or the other way around? I tried the open reflex sight and was not satisfied with all the reflections in and on the hood. I currently have a weaver rail on my .22.

Every ring that fits a weaver rail will fit on a Picatinney rail. Most rings designed for a Picatinney rail (square or beefy cross bolt) will not fit on a weaver rail. The Ultradot Micro will not fit on a weaver rail.