Josiah, if you read this - the fix for your Carbine recoil system is... - make the dimensions match Armalite AR-10 components. I don't know about copyright info on that, and what you'll have to do, or if it's even a problem. VLTOR makes a receiver extension for their A5 (AR15) buffer system that is identical in internal depth to the AR-10 Carbine receiver extension - so I don't know what they're doing, in the copyright world. I can tell you this much - I can run the VLTOR A5 receiver extension on my AR-10 recoil system, and there will never be an issue. I can run a genuine Armalite AR-10 Carbine receiver extension with my VLTOR A5 buffer components (on an AR15), and there will never be a problem. The two receiver extensions are identical in internal depth.
Make your Large Frame carbine receiver extension meets the internal depth requirement that is necessary to run the AR15 H3 Carbine buffer, and use an appropriate spring. Not too long, internally - like the one I personally measured on my buddy's rifle... that thing had almost 8" internal depth. No more stacking quarters to take up the extra space.
You solve that issue, and it'll mean alot to customers. No more carriers slamming into lower receiver ears, etc. There are customers out there that don't even know that they are damaging their rifles, every time they fire them. They just don't know.
Doing this would go a long way in improving the 308 platform function...