Having the older version of the Colt/Umarex M4, I have always had trouble negotiating the 180 degree safety. I think I have come up with a way (at least for me) to operate the safety WITHOUT moving my hand from the shooting position! I pulled out the safety lever and drilled a small hole (forgot what size, 1/8" I think) in the center of the pivot point. After heating and bending an allen wrench, and a little filing and grinding, I carefully tapped it into the hole. Have to make sure it's tight, so it won't turn. I put the little red piece of tubing on there just to see it better, but I may take it off. As you can see, you only have to move the lever 90 degrees at a time to reach one or the other with your thumb. It takes one extra stroke, but is FAR easier than reaching around to make the full 180! If you are left-handed, you won't believe how much easier it is! Works great both ways!