A3 Industries 1913 Picatinny Adapter for B&T APC

The B&T APC9 does not present a 1913 Picatinny rear interface from the factory; it uses B&T's own proprietary rear mount, which limits you to B&T's own (expensive) folding stocks and telescopic brace adapters. The A3 Industries 1913 Picatinny Adapter solves that. It replaces the factory end plate with a 6061-T6 aluminum block that presents a standard 1913 rail, which opens the entire universal 1913 brace and stock catalog to the APC9.

Once installed, any 1913 stock or brace bolts on: the Strike Industries FSA folders, the Magpul UCS, the SIG 1913 folding knuckle, and the rest. The adapter retains the original B&T hydraulic buffer (buffer not included) so the platform's signature soft recoil impulse is preserved, and it adds an integral QD sling socket at the base.

This is the single most enabling APC9 upgrade for owners who do not want to pay B&T factory prices for a stock. A3 lists it for B&T APC pistol calibers only; confirm fit against your specific variant before ordering. At $99.95 it costs a fraction of the $625 to $650 factory folding stock and telescopic brace adapters and unlocks far cheaper aftermarket options.