Vltor BCM Gunfighter Charging Handle Assembly AR-15 Aluminum Black

Anyone used, successfully, the VLTOR BCM Gunfighter medium size aftermarket aluminim charging handle? Got mine today from Midwayusa and cannot get it to work. It is so tight, slidding in, that even with the bolt removed it will not slide into the receiver. If successful, did you have to grind on the handle to make it work? Does it need graphite or some other lubricant? Instructions on the package don't really say. It does say 5.56mm on the handle, but online says it fits all AR15's. Nice piece of equipment, hope to make it work. I purchased it to extend the handle, out some, beyond the Luepold scope I've mounted. Any help for a newbie will be appreciated. Thanks guys.

Neil