What is so special about the hex receiver on the 91's that makes it worth an extra $10 to $20 bucks? Just a more rare variation, or does it perform a certain task, like offering a more durable receiver?!?
Well, generally, the hex receivers are older, and there are claims that they are stronger. IMHO, the 91-30 M/N is built about like a railroad spike, but some folks like the idea of a "stronger" receiver. You pays your money, and you takes your pick.