There seem to be a few misconceptions about shotguns in general, sub-gauges, and 20 gauge in particular.
Despite what you see in the movies & on TV, You need to aim (not the same type of aiming as a rifle) a shotgun. It has a pattern that most of the shot stays in. Just pointing it in any direction, say North, WILL NOT hit and kill everything in that direction! It also takes time for the pellets to reach the target, so you must lead a moving target, preferably by swinging the shotgun, not by stabbing the gun some number of inches (or feet) ahead of the target and pulling the trigger.
Despite what the troll said earlier, WWI shotgun ammo isn't like modern ammo! Yes, police and military use 12 gauge. But it is no longer All brass or paper hulls! It is no longer loaded with black powder or to BP pressures or velocities! If the Military wanted the biggest and the best, THINK 4 BORE, 4 ounces in every round! 10 gauge was a popular gauge back then too, why not 10? Because in that time frame, 10 gauge had no advantage over the 12 gauge of the day!
Subgauges, especially 20: There are more than one subgauge, currently there are 20, 28, & 410, with semi obsolete 24, 32, 9mm and 320 having all been made in the first half of the 20th Century. Mr. Ayoob made a small error (probably a misprint) about standard 20 gauge payload, it is not 5/8 ounce, that is the standard payload of 28 gauge. 20 gauge has a standard loading of 7/8 ounce at 1200 fps, some brands offer a 3/4 ounce load at faster speeds from 1250 to 1400 fps. And least of all is the 410. The standard 3" shell is 11/16 ounce at 1155 fps and the 2.5" shell is 1/2 ounce at 1200 fps. There are "Express" and specialty loadings in all gauges, but 1 ounce in 20 and 28 are pretty common. (one ounce of shot in a 410, just the shot column is almost 3.5 inches long! so no loads are available.)
20 gauge 7/8 ounce in field loads or target loads, will do anything a 12 gauge field load will do, WITH LESS RECOIL! I haven't bothered to shoot any of my 12 gauges in 4+ years, In the spring of 2018 I set a new personal best with a 20 gauge of 45/50 in Sporting clays, beating my old personal best of 44/50 that was done with a 20 gauge in 1999, yet I never bested it with a 12 gauge in around 750 to 1000 attempts! In fact, for the last 4 years I only shot the 20 gauge in that one 10 week league, and have been shooting 28 and 410 (2.5") exclusively! In reality my scores now rival my 12 gauge average with a 410! The point is IF it can be shot and killed with a 12 gauge, you can do it with any shotgun! So why do people use a 12 then or a 20 for that matter? the bigger amount of shot makes a slightly bigger pattern (and more dense too) with the same amount of choke. And that covers up for our poor shooting. In Fact; the great shooters that run a 200 bird Sporting Clay tournament with a 12 gauge, usually get 198 to 200 with a 28 and a 410! The key isn't to have lots of shot, it is to place the pellets you have intercepting the target, weather clay or game!
That being said, Do I want to defend my wife and home with a 410? Not really! But I know I could if I had too! After touting the exploits of the 410 and 28, 20 gauge is a easy payday waiting to happen!
The only thing stopping any person form shooting better than I do (which is very common!) is that you need to get out and shoot your gun! Last year I fired over 5000 410's and about 2800 28 gauge, in guns that I have been shooting since 2005 (when I bought them on close out!)
I own 3 O/U 20's, 2 SxS 20's, 1 semi auto and 3 combo guns. I was shooting 2 to 3 thousand rounds of 20 a year until 4 years ago. I went to the smaller gauges because shot reached $45 a 25 pound bag, and with 410 you get 800 rounds verses 400 with one ounce loads or 450 with 7/8 ounce. (in 1997 you could get a bag for less than $9 on sale!)
My wife knows and loves her 20 gauge, but I would rather use a M-1 Carbine in the house! My neighbors are more likely to survive an intruder in my condo!
Ivan
