Squires & Bingham/Armscor M1600r grip

[ronsnighttrain]

I have a Squires& Bingham m1600r (ar15 style), has anyone changed the grip on it with a more ergonomic genuine m4/ar15/m16 grip? It looks the same, but I don't want to spend the money on one if it won't work

 

[ronsnighttrain]

I borrowed a m2 style grip, and it doesn't fit. The top part that slides over the lower receiver is smaller on the ar15 grip. All other dimensions are the same, unless you take a dremil and shave about a quarter of an inch off the inside.If I find a cheap one at the local gun show then it isn't worth it.