The BCM MK2 Buffer Mod 1 is a bare intermediate-length buffer for AR-15 and M4 rifles, sold on its own for shooters who already run the BCM MK2 receiver extension.
This is the buffer only — no receiver extension, no spring, no castle nut, no end plate. It is the replacement or re-weighting part for an MK2 system you already own.
Read that first line twice before ordering, because the two BCM part numbers look alike and are not alike. This listing is the bare BFMK2 buffer. If you do not already have a BCM MK2 receiver extension and a Mil-Spec M16 rifle action spring in the rifle, this part will not fit anything you own — you want the complete MK2 Recoil Mitigation System Mod 1, which contains this same buffer along with the tube, the rifle spring, the castle nut and the QD end plate.
What you get is the mechanism itself. The MK2 buffer is machined from 7075-T6 aluminium and hard-coat anodised, and it runs a longer internal counterweight travel than a carbine buffer with an internal spring to quieten the counterweight as it shifts. Longer travel means less bolt bounce and a more consistent carrier velocity, which BCM covers under US Patent 10415907.
Buffer weight is the tuning lever. T2 is 5.6 oz (160 g) and T4 is 7.4 oz (210 g), and the heavier the buffer the more mass has to be moved and returned on every stroke. On a UK straight-pull AR-15 that stroke is worked by hand, so buffer weight and spring rate directly set how the action feels under the palm and how positively the carrier returns to battery — the shooter is the cycling mechanism, and they feel this component every single time.
Why shooters choose the MK2 Buffer Mod 1
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Bare buffer, sold alone — the correct part when you already run an MK2 system and want a different weight
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Increased counterweight travel — reduces bolt bounce and steadies carrier velocity
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Internal spring — quietens the counterweight as it shifts
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7075-T6, hard-coat anodised — the same construction standard as BCM's complete system
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Two weights — T2 at 5.6 oz (160 g) and T4 at 7.4 oz (210 g) to tune the stroke
What the MK2 Buffer Mod 1 fits
This buffer fits the BCM MK2 receiver extension only, and must be run with a Mil-Spec M16 rifle action spring. It is not a carbine buffer and will not work in a standard carbine receiver extension, and a carbine spring must not be substituted — BCM is explicit that incompatible components can damage the rifle and injure the operator. If you are starting from a standard carbine buffer system, buy the complete MK2 Recoil Mitigation System Mod 1 instead; it includes this buffer plus everything else the conversion needs. One further note on the MK2 tube itself: because it is roughly ¾" longer than a carbine extension, some Mil-Spec stocks will not collapse all the way back to the castle nut.
Specifications
| Platform |
AR-15 / M4 |
| Fits |
BCM MK2 receiver extension with a Mil-Spec M16 rifle action spring — nothing else |
| Type |
Buffer only — intermediate length, bare component, no tube or spring included |
| Material |
7075-T6 aluminium |
| Finish |
Hard-coat anodised |
| Weight |
T2 5.6 oz (160 g) · T4 7.4 oz (210 g) |
| Brand |
Bravo Company USA |
| MPN |
BCM-BFMK2-M1-T2 · BCM-BFMK2-M1-T4 |
Only buy this if the MK2 tube is already in the rifle. Order the MK2 Buffer Mod 1 today — in stock at Xtreme Tactical Gun Parts with free tracked UK delivery in 7–10 days.
Explore more: AR-15 Parts & Accessories, Rifle & Shotgun Stocks or browse all Bravo Company USA.
