FN 545 MRD .45 ACP vs Glock G21 Gen5 MOS .45 ACP

Both are optic-ready full-size .45 ACP strikers within 0.9 oz of each other (30.0 oz for the FN 545 MRD .45 ACP, 29.1 oz for the Glock G21 Gen5 MOS .45 ACP). Capacity favors the FN at 15+1 vs 13+1, while its listed trigger pull is heavier, about 6 lb vs 5.8 lb. The Glock is the longer gun: a 4.61" barrel and 8.07" overall length against 4.1" and 7.7", with a 0.83" longer sight radius (6.93" vs 6.1"). The FN is 0.49" taller (6.0" vs 5.51") and 0.07" wider (1.45" vs 1.38"). MSRP is $930 for the 545 and $700 for the G21, and the Glock ships with three magazines to the FN's two.

Pick the FN 545 MRD if:

• You want two more rounds of .45 per magazine (15+1 vs 13+1)
• You want driftable steel co-witness-height sights
• You want the shorter 7.7" overall length and a loaded chamber indicator with no manual safety

Pick the Glock G21 Gen5 MOS if:

• MSRP is $230 lower ($700 vs $930) and it includes a third magazine
• You want the 6.93" sight radius and 4.61" barrel, both the longest of the two
• You want the lower, narrower profile: 5.51" tall and 1.38" wide vs 6.0" and 1.45"

Both are cut for an optic and weigh within an ounce of each other, so the trade is clear: two extra rounds for $230 more, or a longer sight radius for less.