Buffer Tubes & Springs
494 products · page 1 of 17
The buffer system absorbs the bolt carrier's recoil and pushes it back into battery. It has three parts that have to match: the buffer tube (receiver extension), the buffer and the action spring. Carbine buffer tubes take collapsible stocks, rifle tubes are longer for fixed stocks, and pistol tubes have no stock notches. Heavier buffers (H, H2, H3) tame overgassed rifles, short barrels and suppressors.
Tubes come in mil-spec and commercial diameters, which decides which stocks fit, and a buffer tube kit bundles the whole system in one box. Compare tubes, buffers and springs below and add them to your build so MyGunLab can check that the system matches.
Read our guide: How to Build an AR-15: Parts List, Tools & Steps
Buffer Tubes & Springs: common questions
Which buffer weight should I use?
A standard carbine buffer (about 3 oz) suits most 16-inch builds. Try an H (about 3.8 oz) or H2 (about 4.6 oz) if the rifle is overgassed, shoots suppressed, or throws brass far forward.
Carbine, A5 or rifle buffer system?
Carbine is the most common, with collapsible stocks. A5 uses a slightly longer tube and spring for a smoother cycle with A5-compatible stocks, and rifle length goes with fixed rifle stocks.
What's the difference between mil-spec and commercial buffer tubes?
Mil-spec tubes are slightly thinner and usually made from stronger 7075 aluminum; commercial tubes are slightly wider with a sloped back. Your stock has to match the tube.
What's in a buffer tube kit?
Usually the buffer tube (receiver extension), buffer, action spring, castle nut, end plate, and the buffer retainer and its spring. Some kits include a stock, so check the listing.