As my readers know, I purchased this new 10mm Glock 20 Gen 5 from Kittery Trading Post about 6 weeks ago. I intend to use it as my back up for bear hunting over bait.

 The Gen 5 supposedly has a trigger spring enhancement, enabling a smoother trigger and improved trigger reset. But I did not find it very smooth. 

After 40 rounds or so it stopped cycling, after the first trigger pull, the trigger did not reset. 

I shot it with 180g, 200g, and 220g FMJ’s. It didn’t like the 220g and it stopped cycling. Then I could not shoot the 180 or 200g bullets after the first trigger pull.

Accordingly, the pistol was sent back to Glock.

I received it back in a month, and tested it with 180g, 200g and 220g at 10 yards with 5 rounds each of the three bullet weights. All rounds cycled as they should and the trigger pull seemed much smoother. See the 10 yard 5 shot bench groups below.

The 200g ammo I used on the target above was FMJ CCI Blaser’s with aircraft-grade aluminum cases. They cycled well and were cost effective at $29 for 50 rounds vs Brass cases at $40 for 50 rounds. I bought more of these as I may not reload them. Speed is 1050 fps=489 ft-lb

The 220g hard cast coated ammo was Underwood High Performance 1200fps. They certainly kicked more but grouped very well. Cost $30 for 20 rounds. Velocity 1200 fps=700 ft-lb

The 180g hard cast was made by UMC/Remington and recoil was similar to the 200g CCI Blaser’s. Cost $41 per 50 rounds. Velocity 1150 fps= 528 ft-lb.

Note: My 45ACP shoots 230g Blazers at 830fps=351 ft-lbs. Not a great bear back up. But +P Underwood ammo can shoot 255g at 925fps=484 ft-lb. 

The 10mm beats even the +P 45 ammo and 10mm Glock has a 15 round clip

UPDATE 25 March 2024

I adjusted the rear sight slightly to move groups to the right from the same 10 yard distance, see below.

Upper left bench groups are 180g Remington UMC loads and 5 tight shots in center are terrific and power is 528 ft-lbs. Lower left 2 shot 220g are great but very expensive and are heavy in recoil. Lower right group is Blazer 200g just left by an inch but not as much energy as the UMC 180g.  So far the 220g seem best with delivered energy but 180g have less recoil. I need to shoot with both speed and accuracy, thus more practice is needed.

End of update

The cost effectiveness of the 10mm Glock 20 Gen 5 makes it very attractive as a hunter or hiker/camper side arm for dangerous predators.  Just practice!

Good Hunting!