I touched upon this in another thread, but based upon the responses I got, I felt I was not communicating effectively. So here it goes in its own thread. Please weigh in on this if you want.
I assume most if not all of you have non-AR style rifles and have taken off the recoil pad at some point. The stock butt on non-AR style rifles typically have a flat area with a cutout for access to the bolt and nut that hold the stock snugly to the receiver. They do not rely upon the tension on the recoil pad retaining screws to hold the stock snugly to the receiver. In an AR, its just the opposite. The stock is for the most part a hollow shell with little flat area to support the pad and the top screw that goes into the buffer tube is totally responsible for how securely the stock is held to the receiver. Without it, the stock slides freely back and forth on the buffer tube.
Most recoil pads are designed with the non AR butt in mind. With the exception of the Morgan pads, they have a plastic plate for their base. That plate is designed to hold the recoil pad securely to a mostly flat butt surface and that's all it is designed to do.
Enter the Sims Limbsaver Model 10401 recoil pad. It is an excellently designed and manufactured product. Much to our good fortune, it provides a reasonable fit to an AR butt profile without modification, despite not being originally designed for that purpose. Though its retaining screw holes align reasonably with those for an AR, they are not designed to bear the stresses associated with being the sole provider of force needed to immobilize the A2 stock. Especially without any flat area to support them. They do allow for installing them over top of the standard A2 trapdoor plate by simply using longer screws. That provides for better support of the Limbsaver, but the screw that provides stock retention force still applies a significant squashing effect upon that thin plastic plate and over time it may displace the plastic and fail.
With the advent of the Thumper class of AR style rifles, stresses far beyond Eugene Stoner's original design are being inflicted on the A2 stock. The use of extra weight fixed to the inside of the A2 stock compounds those stresses in a way he did not foresee also. Now, not only is there compression of the stock during the rearward recoil impulse, there is extension stresses when the rifle rebounds forward. The heavier the stock, the greater the moment of impact upon that poor buffer tube screw and the underlying plate it rests upon. Add to that, one or more of those spring-weight recoil reduction systems and now you have the dead-blow hammer effect to boot. If you weight you stock, either passively or actively, I recommend avoiding using the Limbsaver alone. You will be better off installing it over top of the standard trapdoor plate with longer screws. The slight loss of aesthetics is a small price to pay for durability.
Hoot