Shotgun Gauges Explained – Shotguns 101 #3

Shotgun Gauges Explained – Shotguns 101 #3

The shotgun world is a mess of old standards & notations, and nowhere is this more evident than the way we define bore diameters. Just about everyone is familiar with terms such as 12-gauge or 20-gauge, but what exactly does gauge mean, and how does it translate to an actual diameter?

This video explains the history and math behind the gauge system used to define shotgun bores, and discusses the shotshell sizes in use today.

Please note that any comments on the relative popularity and availability of the shotshell sizes and loads discussed here are from a North American perspective. Things may be different in other parts of the world.

The Shotguns 101 video series focuses on general shotgun topics. I already have a lot of ideas for future videos, but I’d still like to hear any suggestions you might have.

I recommend watching this video with the annotations turned on. I’ll be adding various notes to provide further details and address some common questions and potential points of confusion. There will be no giant flags blocking the video, and absolutely no begging for subscriptions or likes.

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  1. Rob Ott on October 27, 2021 at 5:25 pm

    Was a great video into you got into the BS home defense tangent.

  2. Elephant in the room on October 27, 2021 at 5:25 pm

    Most excellent video 👍

  3. Miguel Ángel Simón Fernández on October 27, 2021 at 5:26 pm

    .410 has a relatively high pressure and a high aspect ratio, that is, the small diameter compared to the length. Also because it often uses fast burning ball powder case deformation and separation issues are not uncommon.

  4. LaSalle jr on October 27, 2021 at 5:27 pm

    4:49 him: the 20 gauge is a family friendly gun
    (The mont américain thing i’ve heard)

  5. Kesley Cottrell on October 27, 2021 at 5:28 pm

    I happened to finally find a 28 gauge side by side. It has quickly became one of my favorites. It’s a close tie with the 16 gauge side by side.

  6. beans bros on October 27, 2021 at 5:29 pm

    *racks shotgun* so long gay bowser

  7. cheezkid26 on October 27, 2021 at 5:29 pm

    imagine a 1 gauge

  8. __ HJG__ on October 27, 2021 at 5:31 pm

    Great stuff – really enjoyed it!! hope you make some new ones soon…

  9. Elite Sniper on October 27, 2021 at 5:33 pm

    Man 4 10 is fun it might be a bit weak but it is too fun to worry about its power

  10. David Alexander on October 27, 2021 at 5:34 pm

    My old 1914 12 ga. Double will put a lump from hades on your shoulder if you pull front trigger first only did it once . Lol.

  11. Brian JOnker on October 27, 2021 at 5:34 pm

    So which one is best for shooting pigeons?

  12. Coopernation official on October 27, 2021 at 5:36 pm

    Did he just say inexpensive ammo

  13. sniper 3-2 on October 27, 2021 at 5:36 pm

    I remember my first shotgun was a .410 then I upgraded to 12 gauge

  14. Mark O on October 27, 2021 at 5:38 pm

    Wtf is an "industrial shotgun"?!?!?!

  15. Marc on October 27, 2021 at 5:39 pm

    Why are my 12-gauge shells red and not blue? Did they change the colors?

  16. Whicker on October 27, 2021 at 5:39 pm

    Synchronizer—-> why r u talking so fast? It’s impossible to follow u.

  17. JoeBarb JB on October 27, 2021 at 5:41 pm

    Sorry loved it, but the math tax my 75 yr old brain.

  18. David G on October 27, 2021 at 5:43 pm

    I fired a 10 gauge once. Just once lol

  19. Duckodb _ on October 27, 2021 at 5:44 pm

    Every time we go to the range and shoot skeet we have a 24 gauge and a 32 gauge with us. My O/U 32 gauge is my wife’s favorite gun. I prefer the 24 over everything else personally. They never get mentioned in these comparison videos.

  20. John De Sade on October 27, 2021 at 5:46 pm

    Thank you fro mentioning the 4-gauge punt gun; I still have my grandfather’s punt gun and shoot it at least once a year at family reunions…my oldest brother is an experienced loader and keeps me in demo ammunition!

  21. Brad Johnson on October 27, 2021 at 5:49 pm

    Had a 16 gauge, it was a sweet shotgun!

  22. Steven Mann on October 27, 2021 at 5:49 pm

    I personally think a 20 gauge is pretty solid. I own several hand me down 20 gauges.

  23. Studebaker on October 27, 2021 at 5:51 pm

    Far too fast to appreciate this content.

  24. Synchronizor on October 27, 2021 at 5:51 pm

    Hey all you new viewers, glad you found your way here. Lots of folks in the comments section asking about the 4- & 2-gauges. If you want info on & examples of guns in those bore sizes, here are some recommended videos, both from the excellent Forgotten Weapons channel:

    4-bore (same thing as gauge) stopping guns:

    2-gauge custom double-barrel:

    There are several reasons I didn’t get into the monster gauges in this video. First and foremost, they’re really not in common use; there aren’t even many of these guns in circulation aside from a few surviving historical firearms (often not in useable condition) and a rare custom-built piece here and there. In this video, I wanted to focus on gauges that are in common use; the options that a new shotgunner would be choosing from for their first scattergun. Getting into the weeds on antiques doesn’t really fit into this video’s intended scope.

    Second, there was a lot more variation in these larger sizes, as was often the case for shotguns in general back in the days of 4-bore safari guns and large market hunting shotguns. Actual bore diameter and (for cartridge guns) shell/chamber dimensions varied quite a lot. Ammunition was rarely interchangeable between guns of different manufacturers, and the standard gauge formula based on lead ball weight wasn’t always adhered to very closely. For example, many waterfowl guns marked as 4-gauge were actually more like 6-gauge by the formula. Again, a lot of weird details and potential confusion to try to tackle in a video that’s really meant to cover the basics and explain the currently-relevant options for shotgunners today.

    Thanks for watching, and please don’t hesitate to ask questions if you have them.

  25. fcfdroid on October 27, 2021 at 5:52 pm

    Just learned more than I thought about shotguns 😂

  26. Plongus on October 27, 2021 at 5:55 pm

    imagine a negative 12 guage

  27. Chris Muir on October 27, 2021 at 5:55 pm

    To much math for me I will keep using my little bang and big bang

  28. Zevo on October 27, 2021 at 5:56 pm

    one of the first shotguns i ever fired was an 8 gauge double barrel. and let me tell you, it scared me off shotguns for a while. that thing packed a punch

  29. Taylor Mischel on October 27, 2021 at 5:56 pm

    Inexpensive and easy to find… funny

  30. Ye Pirate's Workshop on October 27, 2021 at 5:57 pm

    This was really, really informative and I’ve been totin’ shotguns all my life. (Age 66 now.) You gave me a ‘bad’ idea, though. I’m gonna’ have to make my next black powder flintlock into a "O" gauge shotgun. That ought to be a hoot to shoot!!!

  31. Colin L on October 27, 2021 at 5:58 pm

    Glad you focused on the 16g. I got two 16g guns. One is 75 yrs old, other is 60 something. Great guns but hard to find 16g shells.

  32. mic stone on October 27, 2021 at 6:02 pm

    thanks answered some questions I had
    what about you firing those 4 bore weapons FORGOTEN WEAPONS
    why name change

  33. Henry Butchy on October 27, 2021 at 6:03 pm

    I’ve had the pleasure of trying 20-30 diff shotguns. For target accuracy, I just love the .410. it just works for me. But that guns fails at skeet (gotta go 12). YMMV.

  34. Lou Cifer on October 27, 2021 at 6:06 pm

    Gun makers should bring back the 16gauge and make 3in and super mag 31/2 I think it would make a great comeback

  35. COMMUNIST MONKE on October 27, 2021 at 6:06 pm

    I like shooting my 20

  36. Noah Spurrier on October 27, 2021 at 6:08 pm

    I really like .410. It’s like the 22 of shotguns.

  37. Marc on October 27, 2021 at 6:08 pm

    So you shot the intruder with your .410 shotgun?
    Why did he get away?
    He was wearing a flannel shirt.

  38. COMMUNIST MONKE on October 27, 2021 at 6:09 pm

    Have you ever heard of a punt gun?

  39. David Alexander on October 27, 2021 at 6:09 pm

    A 410 double barrel does pretty good when you shoot both at the same time feels like a mag 20 gauge.

  40. daniel clermont on October 27, 2021 at 6:10 pm

    Informative thankyou.

  41. professornuke on October 27, 2021 at 6:13 pm

    Circuit Judge guy kills you with a couple .410’s and a couple .45’s to make sure.

  42. Kansas Hunting/Fishing on October 27, 2021 at 6:14 pm

    I love my .410.

  43. Gurpreet Singh on October 27, 2021 at 6:14 pm

    Small gose LG large

  44. Jeremy Pike on October 27, 2021 at 6:16 pm

    .410 seems to have just disappeared as of recent times. 28 gauge seems to have taken it over. My grandpa had an old sawed down 8 gauge he kept under the bar he ran. In his time it was legal to modify a gun to tailor it to your needs which is what he did. Now you can’t find 8 gauge shells which sucks. Recently I bought a bull pup semi auto magazine fed 12 gauge. I’m pretty happy with it it’s short as a bull pup usually is but has an even longer barrel than most standard shotguns comes with 3 different chokes and can shoot 3" mag. Pretty much a perfect home defense gun plus it’s legal where I am to hunt with a 5 round gun.

  45. Long Haired Country Boy on October 27, 2021 at 6:18 pm

    The first shotgun I shot was a .410 double barrel that belonged to my late Grandfather. I wound up inheriting it from my Uncle before he passed. I could have sold it several times over the years but I’ll pass it down to one of my nieces or their kids if they have any.

  46. Carl Hansen on October 27, 2021 at 6:19 pm

    The 410 shot gun is also known as a 36 ga, in Europe. You should know that!

  47. Agxtaxor on October 27, 2021 at 6:20 pm

    I came here because I am American. Not because I am a mathematician

  48. Enigma Wyoming on October 27, 2021 at 6:22 pm

    Personally, I wouldn’t want to defend my home with a gentlemanly 16 gauge shotgun against a tweaker that is invading my family’s space. I ain’t in the mood to be a gentleman at that point.

  49. draconus56 on October 27, 2021 at 6:23 pm

    Grew up with 16 bolt gun still enjoy borrowing it.

  50. Bora Yurtoren on October 27, 2021 at 6:23 pm

    .410 is called 36 gauge over here in Turkey, local manufacturers make very realistic looking shotgun replicas of AK-47 and AR-15 assault rifles that shoot .410 cartridges. Turkish laws does not permit civilians to own assault rifles so these replicas really attract huge demand.