The D4RGC is a very good sight and a good value. I did however have one real problem with sighting it in. I was mounting it on a Remington 1187 12 gauge shotgun with rifled barrel and cantilever scope mount. The problem was that unlike most rails that are purchased to mount on a gun, the cantelevered mount is solid across the top without the hollow center. Thereofre the center post that the reticle adjustment is mounted on, contacted the top of the rail when fastened down makeing it impossible to adjust the reticle to the left or right. I ended up having to grind a groove in the center of my rail so that the reticle adjustment post could move. Once I did that I was able to adjust the sight and it seems to be working fine. I'm just not sure if I damaged it trying to adjust it before I figured out the problem, as I kept turning the adjustment and seeing no movement either way of the reticle. I haven't had the oppertunith to get out and shoot for the last couple months as none of the shooting ranges around here allow shotgun slugs to be shot. This is Austin,Texas and they don't know what shotgun slugs are down here.
This review was written in the old system and had content requirements that are different than reviews written today.