When Eric first mentioned the "CAR-15/M4 360° HK STYLE FLIP-UP SIGHTS" sights to me, I'll admit I was less than ecstatic about another pair of HK style sights hitting the market. However, since I was going to be doing a few days worth of heavy caarbine training, I figured it would give me a chance to point out all the reasons I'm not found of this style of BUIS.

Once again, I find that things I've not been found of in the past have been improved upon. One of the largest sticking points with me is that I feel the sights should have a varying set of apertures instead of just the tiny ones calibrated for elevation. Indeed, this concept stayed with me throughout the testing, but instead of it being a major point, I found that for all my close in work I used the largest aperture ( .160") anyway, and that it made little difference. When working hanging bowling pins to simulate engagement of moving targets at distance, I found that the smaller aperture (.070") wasn't anywhere near as bad as I thought it would be. In fact, I found myself liking it quite a bit. The small size makes for solid precision work, and the larger size works well for closer in.

This left the 200 and 300 yard apertures. Since there was no difference in size, it left you with a pretty simple method of estimation, and dialing in your BUIS to your chosen distance. Again, this isn't my favorite method, but I found it worked well. For some reason I keep thinking that varying size apertures would work better, but the current layout worked well.

The BUIS is designed to work with the standard "F" front sight base, and is set for military M855 (62 grain) loads. As with any BUIS, you need to dial it in to your own particular loads and go from there. I found it worked nicely with the ammo that I fired, which was 55 grain FMJ.

The sight feels solid, and turning the dial/ knob wasn't hard, but wasn't soft enough to invoke concern of it being moved accidentally. I know that some people will wish it locked into the upright position, but it wasn't the end of the world for me. The BUIS was easy to fold into its upright position. I had no issues with the knob on the side, though I can see why Eric points it out. The knob allows for easy tightening, and I had never any issues with it coming loose. I through it on several different weapons through out the testing, and used a coin or knife blade to tighten and loosen each time. The large slot makes it an easy process.

For HK fans, this BUIS will be something they love. After all, it brings the convenience of a folding rear sight along with the HK style diopter that they love. For other shooters, while it might not be love at first sight, this unit is very functional, and I would have no problems using it on my carbines.