Like Picatinny mounts, the ring size on any complete Weaver mount will need to match the scope tube width, i.e. 1”, 30mm, 34mm, etc., and rings are secured around the tube and then secured to the rail at the base. It’s best to match Weaver-to-Weaver systems as the wider Picati...
The M4 flattop upper is essentially the same as the A4 upper. It has a Picatinny rail that supports pretty much every optic and accessory on the market. This makes it the most popular choice for most factory and custom AR-15s. Complete vs Stripped Upper Receivers Complete upper assemblies a...