What's the details on the recoil system on this one? Is it all Armalite AR-10 Carbine recoil system parts? Get this buffer from Clint @ heavybuffers.com, if that's the case, and it'll solve what's going on right now. Guaranteed.
Scroll down on this page, and look for this one:
https://heavybuffers.com/ar10carbine.html
For .308 ARs with Extended Receiver Extensions:
XH Carbine Buffer (8.5 oz) w/.308R Buffer Spring - $140
XH Carbine Buffer + .308 Rifle Spring
Quantity:
If you have an extended (7-5/8" deep) receiver extension on your gun I recommend an XH carbine buffer and a .308 rifle buffer spring. This includes VLTOR A5 tubes and the Magpul UBR Gen2 stock. Many .308 rifles come from the factory in this configuration - LMT, S&W, LaRue, POF, etc.
My note - this is next up on my .358 Win AR, to control that heavy-kicking bastard. It'll happen before November, for sure, be test fired and solved, and be ready to go by Vet's Day weekend.