Common rifle buffer for .308ARs, but the receiver extension depth is about an inch TOO deep. Internal depth for a rifle receiver extension should be 9 11/16". Please re-verify that number, and make sure it's internal depth, and not overall length... The earlier mention of the spring is correct - wrong one. Armalite EA1095 spring will be the one to use, and solve that issue quickly.
BCG weight... BCG weight is reciprocating mass, just like buffer weight is. It's weight, sitting there, that had to control the force of the .308 Win cartridge, and cycle a gas operated gun. Normal full-mass .308AR BCGs are around 18.87 ounces (Fulton Armory .308AR chromed BCG is that example). Though yout buffer weight is correct (close to 5.4oz), you have effectively taken 6 ounces out of that reciprocating mass, by using that lightweight 12-ish oz BCG. That's a cycling issue, right there.
Now, you can fix this quickly, and keep using the Ti BCG in your gun, but you're gonna need one of the 10oz rifle buffers from Slash (www.heavybuffers.com). That will get that weight back into the reciprocating mass, that you need to be there.
This isn't a Race Gun - Standard parts will work fine, at standard "specs" - for lack of a better term. Using "specs" in a sentence with ".308ARs" is an oxymoron... Fancy lightweight parts are just going to complicate the process of reliability, unless you're using this gun to make money on the professional 3-Gun circuit...