Put in an order for an A3 from McMillan and noticed them trending toward 4" rails on the bottom. I'm just going to use my rail for attaching an Atlas. Seems like a lot of rail for just a bipod. Can anybody explain the trend towards longer rails? Advantages/disadvantages... my imagination is coming up with being able to handle more stress from the bipod and a longer surface to sit flatter on a bag when the bipod isn't mounted, but we know what imagination can do to a guy.