If you're a gambler, give this a go - TRYBE Defense AR Ambidextrous Enhanced Mil-Spec Charging Handle

I have had two of these. First was returned for being out of spec, didn't work at all. The second one I received was also out of spec, but technically still worked albeit poorly. The issue is simple, poor QC/machining. It's a cheap, good looking ambi charging handle, if that is enough for you to try this out against better judgment, on your head be it. Just remember when you find yourself mortaring your AR to get this unstuck or when you charge your AR and it sounds like nails down a chalk board, you were warned!