One of my go-to buffers - Dark Storm Industries DS-15 H2 Carbine Length Buffer 4.5 oz

I have several of these running with the JP Enterprises Enhanced buffer spring. As we all know, many AR-15's come over-gassed from the factory to ensure they run with whatever people will put through them. I, for one, run only high-powered ammo so when I get one of these guns, I see my casings ejecting at 1-2:00. I have at least 3 carbines and rifles running this buffer to calm down the action and am completely satisfied with their application. I even have one in reserve.

Yes, I know, the true optimization is in the gas block and gas tube. I've done that too on my highest priority guns. Adjustable gas blocks and restricted gas tubes. But on my "let's just have fun" guns, I find the JP springs and this buffer most satisfactory.