B&T GHM9 & SPC9 Accessories & Upgrades: Triggers & Mags

Buy magazines and control fixes before triggers and suppressors. A matched magazine and a selector that your thumb can work under load change how the gun runs today; the forced-reset trigger and the can are higher-cost changes that carry real fitment and legal homework. Optics and a light sit in the middle, since both top rails take standard Picatinny hardware.

Key insight: the GHM9 Gen 2 and SPC9 are not one platform with two names. The magazine well and upper shelf height on the actual gun decide which trigger, magazine, and charging handle fit. Identify the lower and upper before spending on the high-dollar parts. For the wider platform context, our B&T SHOT Show 2026 coverage tracks the current GHM9 family, including the GHM9 Retro.

The $525 Rare Breed FRT-SG3 is the trigger to buy on a GHM9 or SPC9, because it is a purpose-built drop-in pack for the SPC9, GHM9, and GHM45 rather than an AR trigger forced into a B&T lower. It ships with a B&T-style ambidextrous three-position selector plus the hammer and trigger axle pins, breaks at 4 to 4.5 pounds as a two-stage in semi, and runs a 5 to 5.5 pound single-stage in forced-reset mode. As of July 2026 it is also factory-integrated: Rare Breed and B&T USA assemble and test it in SPC9 and GHM9 models, covered in our Rare Breed x B&T USA factory FRT-SG3 report. It does not fit the APC family despite the resemblance, and a Lingle lower needs AR-style three-position selector parts that are not in the box.

The $515 Triggered Company assisted-reset pack is the alternative when you want a lighter pull and your lower fitment is confirmed. Its listed 3.75 to 4.1 pound pull is lighter than the FRT-SG3's forced-reset mode, and it uses 17-4 stainless and 4140 chromoly wear surfaces with a three-position control. The catch is upper shelf height: the current warning excludes GHM Gen 1 high-shelf uppers, and some guns sold as Gen 2 shipped with a Gen 1 upper, so confirm the actual shelf before ordering. It also does not fit B&T special-edition aluminum lowers, and it is sold in Low Shelf and Lingle Lower configurations. For how the assisted-reset mechanism behaves in hand, see our Triggered Company assisted-reset review.

The best broad control upgrade is the $72 HB Industries modular selector kit, because it replaces the full selector with a 7075-aluminum shaft and lets you configure a long lever, short lever, or a delete cap on either side. That solves the factory right-side lever rubbing your trigger finger on the compact frame without giving up ambidextrous control. HBI lists it across the APC, GHM, and SPC families, but does not guarantee operation with aftermarket AR-pattern triggers and notes fit can vary with aftermarket aluminum lowers.

If the only complaint is a stiff selector, the $8 HBI reduced-weight springs are the cheapest fix on this page. Both replacement springs cut selector resistance by HBI's stated roughly 30 percent; mixing one HBI spring with one factory spring gives a milder roughly 15 percent reduction. They fit the APC, GHM, and SPC families without touching the selector shaft, and they change selector effort only, not trigger pull weight.

The $100 B&T BT-450076 folding charging handle is a GHM9 and GHM45 part only, installs on the left side, and is explicitly incompatible with the APC9 and APC45. B&T does not list it for the SPC9, so this is the clearest example of a part that does not cross between the two hosts in this guide. It folds against the receiver to reduce the protruding control during transport and sling use, with no receiver modification required on a compatible GHM.

The lower decides. A B&T-pattern lower takes the $50.99 factory BT-30183-N 30-round magazine, which B&T lists for the MP9, TP9, APC9, GHM9, and SPC9 and whose semi-transparent body shows the remaining round count. That magazine is where the shared parts stop: the machine-pistol hosts take the same magazine but none of the rear assemblies or controls, which our B&T TP9 and MP9 accessories guide works through part by part. A Glock-compatible lower takes standard Glock-pattern 9mm magazines instead. B&T sells GHM9 Gen 2 and SPC9 variants with different lower options, so identify the magazine well on the actual gun rather than assuming fit from the model name alone.

How many: a range or training gun wants six to eight magazines to cut reloading interruptions and let you rotate springs; a defensive setup runs three or more. The factory B&T magazine costs more than a common Glock-pattern 9mm magazine, which is one practical reason many owners prefer a Glock-lower configuration. Thirty-round capacity is unavailable where state or local limits apply.

The $299.99 Holosun AEMS Core X2 is the best enclosed red dot for either gun's top Picatinny rail, mounting directly with an included 1.63-inch lower-third mount. Its enclosed 2 MOA emitter shrugs off the debris a compact blowback action can throw, Shake Awake and a CR2032 give up to 50,000 hours, and the 7075-T6 housing is rated IP67 and to 1000G of vibration resistance. The single-dot Core model drops the Pro's multi-reticle and solar backup, and the 1.63-inch mount rides taller than some shooters want on a compact PCC cheek weld.

For light, the $140.24 Streamlight ProTac Rail Mount HL-X Pro System is the complete kit: 1,000 lumens and 50,000 candela reaching 447 meters, with a remote switch, a Jack-Cap tail switch, retaining hardware, and an M-LOK mount in the box. The integrated clamp attaches directly to Picatinny while the included adapter covers the SPC9's M-LOK forend. The remote-switch configuration is IP54 rather than the tail-switch configuration's IP67, and at 6.6 to 7.2 ounces it is not the smallest option for a compact carbine.

The $636.65 SilencerCo Omega 9K is the compact 9mm can to pair with either host, at just 4.54 inches and 7.3 ounces so neither carbine goes front-heavy. It is full-auto rated, positioned by SilencerCo for PCC and subgun use, and supports Alpha, ASR, piston, and three-lug accessories. The mounting detail is what trips people up: the box includes a three-lug tool, not the required 9mm three-lug mount, and the included direct-thread mount is 5/8x24, so it is not a direct match for every GHM9 or SPC9 muzzle. For a factory three-lug GHM9, add SilencerCo's separate AC2447 9mm Alpha 3-Lug Mount, and confirm the exact host muzzle on an SPC9 before ordering any mount. For the wider field of compact 9mm cans and mounting systems, see our best 9mm suppressor guide.

Federally, the 2025 DOJ and Rare Breed settlement treats one-round-per-trigger-function FRTs for rifles and grip-forward pistols as non-machine guns, with no NFA tax stamp required. State law can be broader: 16 jurisdictions restrict FRTs or rapid-fire activators, counting Florida's legally ambiguous status, while Washington restricts binary triggers but does not ban FRTs. A vendor no-ship list is a shipping policy, not the statute, so confirm your own state and local law before buying rather than reading fit from a retailer's exclusions.

None of this changes the mechanical fitment work above. A trigger that is legal where you live still has to match your lower and upper shelf height, and the selector, magazine, and charging-handle choices are governed by the hardware on the gun, not by trigger law.