My custom build 7" M4 piston

[Zambowhite]

Warface, here is the website http://armsmounts.com/

It's the #71L-F and #71L-R around 90$ for the set I also tried the magpul BUIS but The ARMS sight has an extra feature: the rear sights have a notch above the aperture for close in targets, less than 25m. Hope this helps.

[Hispeedal2]

I don't think I would fault a well-made side charger. Aside from reloads, clearing malfunctions would happen with slightly less movement as well.

The SCAR is an excellent example.

Interesting build.