Lee nailed it earlier with patterning your own gun.
2 3/4" shells is all anyone needs. Heck all I ever use[d] as most guns would not chamber a 3" one anyway.
#3 buck is great, there is a relationship with this payload and the 20 gauge bore diameter. If one patterns shotguns, and takes the time to understand "payload to bore ratio" a LOT of questions will be answered .
If one takes the time to understand bore diameter, forcing cone and how all this works with a loading, lots of questions will be anwered.
Remember, each shotgun is unique.
Each lot of ammunition is unique.
Same gun/ barrel coming off assembly line - can and do differ.
Different lots of same ammunition differ.
Hence the suggestion to buy 5 packs locally of various shells, pattern the gun and then run like hell back to store to buy the same lot the gun performs best with.
Slugs, now I prefer slugs. Old fashion 2 3/4 " Forster slugs are great.
2 3/4" Brenneke - IMO/ IME are really great, just hard to find. I see NO advantage of going to the 3" version of Brennke.
Real Life.
Deer, Elk, Bear, Hogs and other game have fallen to 20 bore guns, #3 Buckshot and Slugs, 2 3/4" only shells.
Granted most times the #3 is used for deer/ elk. Slugs have proven themselves on these game species.
While I appreciate testing by others - I was raised to test for Myself. Pattern board shooting for pattern density , POA/POI , slug groups and all.
Makes no difference how much something penetrates - if the gun does not shoot POA/POI then what good is a pattern/ group if it goes somewhere else than where you want / NEED for it to go??
Mentors were shooting dirt before I was born in mid Fifties.
Why?
Not for "how deep" - instead more for "how did the projectile hold up?"
Because back in the day, they reloaded handgun, shotgun, and rifle loads.
AFTER they patterned shotguns, shot for groups - they wanted to see deformity of pellets / slugs.
They knew the significance of chilled/soft pellets, and hard pellets and effect on deformation of projectiles , performance of pattern density , and all.
Many were making their own "slugs" for shotguns, including 20 gauge, as well as 12, 28 and .410. Naturally they wanted to see how these slugs did POA/POI , groups and ...they learned from removing from backstop, and comparing the same load from a deer <light bulb went off> "Load removed from deer, (game critter) closely matched one removed from dirt".
Scientific Mud/Dirt Test they called it. Keep in mind, I was born in mid Fifties, and Mentors has been doing for quite some time - this was passed down to them!
Understand these folks had been in conflicts, had seen what projectiles do to human beings. They had shot and killed enemy - enemy shot back and some of my Mentors had the "proof". I grew up with Veterans, some amputees and nasty scars and all.
When they reloaded, cast their projectiles - they wanted to know if the thing come apart, after it proved to function in gun,and went where it was supposed to.
Laugh if you want, but a LOT of lead round ball slugs , cast by these "old timers" , fired from 20 gauge shotguns felled LOTs of deer bear, elk and other uses.
Lead ball retrieved (if it did not punch thru and lost) was melted back down, and reloaded again.
20 gauge in 2 3/4" is all one needs...
All we use[d] then and I still adhere to this, is 2 3/4" . Matters get serious, out of shotshells for whatever reason, on is going to feel really powerless if all they have is a 2 3/4" shotgun and someone tosses them 3", 3.5" shells.
Same reason one tosses out 38spl to persons going thru riots, floods, hurricanes, fire or other natural disaster. .38spl fits both a .38spl and .357.
Really not comforting to have someone toss you a box .357 during a hurricane and all you have is a dedicated .38spl in your get and grab bag...or persons passed out .38spls ...
Forget goopy, exotic, Hollywood , Movies and all. Go test for yourself.
While I appreciate the time, expense and effort of testing...
If the gun does not feed or extract a loading ...
If the the gun does not shoot where it is supposed to the loading...
Then what good is it no matter how deep ,or how well the pattern density or group size?
It ain't !
