The Glock G40 Gen4 MOS exists for one reason: to wring maximum velocity from 10mm Auto. The 6.02" barrel is the longest of any production 10mm handgun, adding roughly 50-75 fps over standard 4.6" barrels with full-power loads. At 9.49" overall and 35.45 oz, this is not a carry gun. It is a holster-on-the-hip hunting and woods defense tool, and it does that job better than anything else in polymer.

The extra weight pays off at the firing line. Owners report that the G40 is the softest-shooting 10mm Glock by a wide margin, with the 35.45 oz soaking up recoil that batters the 28.4 oz G20. The 8.31" sight radius is longer than most 1911s, which helps with the iron sights. The MOS system puts a red dot on without milling. The adjustable rear sight is another feature the standard G20 does not get.

One practical note: the G40 is large enough that holster selection is limited compared to the G20. The 9.49" length rules out most standard OWB holsters designed for duty-size guns. Dedicated long-slide holsters from Safariland, Kenai Chest Holsters, and a handful of kydex makers are the usual options. Plan the holster purchase before the gun purchase.