I have a ZKK 602 in 375 and a CZ 550 in 416 Rigby and both have barrels cut to 21" with Barrel band front swivel. Front sight is an ERA (NECG) Universal Screw-On Ramp with Red Fibre optic on both rifles. This ramp provides elevation adjustment and they both handle and shoot very well. I find the 21" length to be most comfortable for me.