ODIN Works H-FRT9 Heavy Buffer (AR-9)

The ODIN Works H-FRT9 is the AR-9 configuration of the H-FRT heavy buffer, a machined 303 stainless body matched to a proprietary flat wire spring and tuned for blowback 9mm carbines running a forced reset trigger. Direct-blowback PCCs have no gas system to bleed pressure; the bolt is driven straight back by case pressure and strikes the buffer harder per shot than a gas-operated 5.56 carrier. On a forced reset trigger that impulse compounds across a magazine, which is why the H-FRT9 carries more mass and a stiffer spring than the AR-15 version and is not a drop-in for a 5.56 host.

AR-9 buffer tuning has historically meant a stacked tungsten weight buffer and a hand-picked stiff spring, calibrated for a specific upper, ammo weight, and trigger. The H-FRT9 is built to make that calibration step disappear by shipping the buffer and spring as a single tuned system. The one-piece 303 stainless body matters most here: stacked weights in a hollow sleeve can shift or rattle under repeated high-rate blowback impulses, and any internal play changes the effective buffer weight at impact. A single machined body has nothing to move, which keeps the buffer's contribution to the cycle consistent shot after shot.

Install the forced reset trigger first, confirm function with the factory buffer, then swap to the H-FRT9 and its flat wire spring as a unit. Do not pair the body with a stock spring or a flat wire from another vendor, and do not run the H-FRT9 in an AR-15 or the AR-15 H-FRT in a 9mm PCC; each is calibrated for one job.