FN 545 MRD .45 ACP vs FN FNX-45 Tactical .45 ACP

Both hold 15+1 of .45 ACP and both are optic-ready, so the split is size, action and price. The FN FNX-45 Tactical .45 ACP is the bigger gun: a 5.3" barrel to the FN 545 MRD .45 ACP's 4.1", 8.6" overall against 7.7", 0.5" taller, 0.13" wider and 3.3 oz heavier (33.3 oz vs 30.0 oz). It is DA/SA with an ambidextrous manual safety and decocker, threaded from the factory, and wears suppressor-height night sights. The 545 is striker-fired with no manual safety and a loaded chamber indicator, on driftable co-witness steel sights. MSRP separates them by $464, $930 against $1,394.

Pick the FN 545 MRD if:

• You want the smaller, lighter package: 7.7" overall at 30.0 oz, 3.3 oz under the FNX-45 Tactical
• You prefer a striker-fired trigger with no manual safety to manage
• $930 against $1,394 matters — $464 less for the same 15+1 capacity

Pick the FN FNX-45 Tactical if:

• You want the 5.3" threaded barrel and suppressor-height night sights out of the box
• You want DA/SA with a decocker: a long double-action first shot, then a single action FN lists at 3.96-5.06 lb, against the 545's 6.0 lb striker pull
• The longer 6.4" sight radius, against 6.1", suits how you shoot

Caliber, capacity and optic readiness are tied, so the choice is whether you are buying a duty-size .45 or a suppressor-ready tactical pistol. The 545 is smaller, lighter and $464 less; the FNX-45 Tactical brings the threaded barrel, tall night sights, manual safety and a single-action pull after the first shot.