Glock G21 Gen5 MOS .45 ACP vs Rock Island Armory 1911 GI Standard .45 ACP

The Glock G21 Gen5 MOS .45 ACP and the Rock Island Armory 1911 GI Standard .45 ACP answer the same cartridge in opposite ways. The G21 is polymer-framed and striker-fired, holds 13+1, runs a 4.61" barrel, weighs 29.1 oz and ships optic-ready with three magazines. The RIA is a 4140 steel single action holding 8+1 behind a 5" barrel at 39.5 oz, 10.4 oz heavier, with a thumb safety, a grip safety, GI-type fixed sights and one magazine. It is 0.08" narrower (1.3" vs 1.38") but 0.47" longer overall (8.54" vs 8.07"), and its trigger is listed at 5.0 lb against 5.8 lb. MSRP is $700 and $420.

Pick the Glock G21 Gen5 MOS if:

• You want 13+1 instead of 8+1, five more rounds of .45 ACP on board
• You want a red dot on the factory MOS cut; the GI Standard has irons only
• You want to carry 10.4 oz less (29.1 oz vs 39.5 oz) and get three magazines instead of one

Pick the Rock Island Armory 1911 GI Standard if:

• You want a single-action trigger listed 0.8 lb lighter, 5.0 lb vs 5.8 lb
• You want the thumb safety and grip safety of the 1911 manual of arms
• You want the thinner 1.3" single-stack grip and an all-steel frame and slide at a $420 MSRP against $700

Count rounds and ounces and the G21 is the answer; count trigger weight and grip width and the RIA is. Nothing in the specs splits the difference.