The Sig P320's modular fire control unit changed how handguns get sold in America. The serialized trigger group drops out of the grip module and into a different frame size, so one registered component works across full-size, compact, and subcompact configurations. No other striker-fired 9mm on the market offers that. The military validated the platform when the U.S. Army adopted the M17/M18 variants in 2017 after extensive endurance testing.

In full-size trim, the P320 carries 17+1 rounds in a 28.3 oz package measuring 8.0 inches overall. The stainless steel slide adds weight compared to the Walther PDP Full Size at 22.3 oz, but the mass helps manage recoil during rapid fire. The SIGLITE night sights ship standard, which saves the sight upgrade most competitors require out of the box. The optic-ready slide accepts common red dot footprints. The 6.5 lb striker trigger has a smooth take-up into a defined break, though it runs 1.5 lbs heavier than the Springfield XD-M Elite's 5.0 lb META trigger.

Run at least 200 rounds through a new P320 before trusting it for home defense. Most owners report flawless reliability from the start, but a break-in period with your chosen defensive ammunition confirms feeding and ejection patterns specific to your gun. The recoil spring settles in after the first few hundred rounds, and owners note the slide action smooths noticeably during that period.