09-26-2011, 03:15 PM
You will want a heavier buffer than the standard 2.9 oz. carbine buffer, but if you're using a Magpul PRS, you'll be fine with the standard 5.2 oz rifle-length buffer. The Grendel has a larger gas impulse & volume than a 5.56 gun, so you need heavier buffers and/or M16 bolt carriers to keep the bolt locked longer.
