I had a PWS mk216 in 308, and running an omega in stock trim just wasn't happening.
it had a carbine length reciever extension so I ordered the slash xh buffer/spring combo. It helped, but it made the recoil impulse really punchy and I didn't care for it. It was still pretty hard on cases also.
After a lot of reading here and other places, I switched to the a5 length extension and an h3 buffer. Tried the stock spring, and the heavy spring from slash and I still really wasn't happy with it.
Ended up making a honking huge buffer myself, that weighed like 11oz iirc, and its was better, but still not great.
Enter the tubbs flatwire. Picked one up and it ran the best it ever had. Softer recoil impulse. Kicking brass out about 3 o'clock. Brass was relatively clean for running suppressed. Then I tossed the h3 back in just for kicks to see what would happen, and that was the setup I settled on until I sold that rifle.
I've used three of them so far. Two large frames, and and one ar15. I need to pick another one up for this LMT that replaced the PWS. Currently its running a sprinco red, brt 50/50 tube, and the stock buffer.