Glock G21 Gen5 MOS .45 ACP vs Glock G30 Gen4 .45 ACP

Same caliber, same 1.38" width, very different footprint. The Glock G21 Gen5 MOS .45 ACP holds 13 rounds to the Glock G30 Gen4 .45 ACP's 10, with a 4.61" barrel against 3.78" and a 6.93" sight radius against 5.91". It is also the bigger gun by 1.10" of length (8.07" vs 6.97"), 0.71" of height (5.51" vs 4.8") and 2.8 oz (29.1 oz vs 26.3 oz). The G21 is an MOS model and is cut for an optic; this G30 Gen4 is not. The G30's trigger is listed 0.5 lb heavier, 6.3 lb against 5.8 lb. MSRP is $700 for the G21 and $570 for the G30, and both ship with three magazines.

Pick the Glock G21 Gen5 MOS if:

• You want 13+1 of .45 instead of 10+1
• You want the longer barrel and sight radius: 4.61" and 6.93" against 3.78" and 5.91"
• You want the factory optic cut, which this G30 does not have

Pick the Glock G30 Gen4 if:

• You are concealing it: 1.10" shorter, 0.71" less grip height and 2.8 oz lighter
• You want to spend $130 less ($570 vs $700)
• You can live with 10+1 and the 6.3 lb trigger

Width is identical at 1.38", so the G30 buys its concealment with grip height and barrel, not with a slimmer gun. The G21 is the one to shoot and mount a dot on; the G30 is the one to hide.