FN 545

The FN 545 Tactical is FN America’s .45 ACP full-size pistol—a professional-grade platform that brings FN’s military and law enforcement manufacturing standards to the .45 ACP cartridge. Built with an 18-round double-stack magazine that holds more .45 ACP than most competitors, a 4.7” threaded barrel ready for suppressor use, a fully ambidextrous control layout, and the FN Low-Profile MRD optics system for direct red dot mounting, the FN 545 is one of the most capable .45 ACP pistols ever produced by a major manufacturer. For buyers who specifically want .45 ACP with no compromise on features or capacity, the FN 545 is the benchmark.

Read our full FN 545 Buying Guide ↓

18+1 Capacity in .45 ACP: How FN Did It

Most double-stack .45 ACP pistols max out at 13–15 rounds because the .45 ACP case diameter makes high-capacity double-stack magazines wide and difficult to hold. FN engineered the 545’s grip with a carefully optimized geometry that accommodates the 18-round magazine while keeping the grip width manageable. The result is a .45 ACP pistol with capacity that approaches 9mm competitors—18+1 vs. the 17+1 of a Glock 17. For buyers who chose .45 ACP specifically for terminal performance but always felt constrained by single-digit capacity, the FN 545 removes that tradeoff entirely.

FN 545 vs. FN 509: Choosing Your FN

The FN 509 and FN 545 share FN’s overall design philosophy and manufacturing quality but are built for different cartridges and use cases. The 509 is a 9mm platform optimized for the modern law enforcement and military market where 9mm dominates. The 545 is for buyers who specifically want .45 ACP—whether for terminal performance preference, suppressor use with subsonic .45, or the history and tradition of the cartridge. The 509’s aftermarket is larger; the 545’s .45 ACP capability is unique in the FN lineup. Both are built to the same military contract standards.

Threaded Barrel and Suppressed Use

The FN 545 Tactical ships with a 4.7” threaded barrel in the standard .578x28 thread pitch used for .45 ACP suppressors. Subsonic .45 ACP—which is any standard-pressure load at or below 1,000 fps—is already subsonic without special ammunition selection, making the 545 an exceptionally capable suppressor host. The combination of a heavy .45 caliber bullet, naturally subsonic velocity, and a quality suppressor produces some of the quietest centerfire pistol report available. For suppressor-focused buyers who prefer .45 ACP, the FN 545 is one of the most purpose-suited hosts on the market.

Ambidextrous Controls and the MRD Optics System

The FN 545 features fully ambidextrous slide releases and magazine releases—functional from either side, not just cosmetically mirrored. The FN Low-Profile MRD system provides a direct slide cut for mounting red dots in a proprietary low-profile configuration that keeps the optic closer to the bore than most adapter-based solutions. Trijicon RMR, Leupold DeltaPoint Pro, and similar optics mount directly. The combination of ambidextrous controls and low-mounted optics makes the 545 appropriate for left-handed shooters and anyone who runs a red dot as their primary aiming system.

See the 9mm companion on the FN 509 page, explore the .40 S&W option on the FN 510 page, or browse the complete FN America lineup.