I guess as far as ultimate structural failing limits, the dual port receiver is weaker then the single port. In all honesty, the next one I order for one of my personal hunting rifles (there will most certainly be more!!!), will be a right port only receiver. I just wanted to try out the true BR design and see what I thought. I like it but for a big game rifle there really is no need.
Strength wise, there is so much steel under the ports and a very substantial top strap as well that I suspect you would never be able to tell any difference in strength between the two designs.
Also, if you look at that rail base its solid steel when you order them. Mine has been milled out in non critical areas on the underside to reduce weight which is a good thing as it would not have made weight otherwise.
But as they come from Lawton, those rail bases have alot of steel in them and only add to the rigidity of the system.
Them combine all that with the longer threaded section and the full length bedding of the receiver and this system is as stable and solid as any other receiver out there of the same diameter.
On the stock, I am not sure if the stock could be ordered with a wider forend or not. I know Tom is working on some new stock designs but I am not sure if that is one in the works. He would be the man to talk to. Go to www.mannersstocks.com
and you can e-mail him and see what he has to offer in a wider forend. I would like a slightly wider forend but so far have not found any fault with this one.
Basically this will be a torture test to see if I can make this barrel tear apart the 200 gr ULD RBBTs. I suspect I will not be able to do this even at very top end safe pressures in this rifle. For the time being I think Rock really hit this one on the head!!