This particular kit comes with a Stainless Steel Buffer weighing about 0.5 lb (8 oz). Kaw Valley Precision also offers this completion kit with other buffer weight options, including 4.3oz, 5.4oz, 7.5oz, and 10oz buffers.
No. This Kaw Valley Precision Pistol Stock Completion Kit will not fit 6-position buttstocks as this is a pistol buffer that does not feature a channel to allow 6-position stocks to fit. It is designed to work with braces like the Tailhook Mod 1 Brace.