You are asking “equivalent caliber” which literally mean same diameter. 12 gauge slug diameter is 0.79″ which is 20 mm (20.066 mm). 20mm Vulcan bullet has same diameter.
When it comes to the cost of 12 versus 20 gauge ammo, 12 gauge shotgun shells will usually be cheaper. … Except unlike buying a car, the difference in price between a 12 and 20 gauge shot won’t be by a lot. Often, it’s only a few cents per round.
As shotguns and shells became more efficient in the beginning of the 20th century, the 12 gauge shotgun became more effective for hunting and the large, clumsy 8 gauge became obsolete. It was banned for waterfowl hunting in 1938 by the Federal Firearms Act.
The 10 gauge has a bore size of . 775″ while the 12 gauge has a typical bore size of . 729″. Further, a 10 gauge shotgun is usually heavier (around 10 pounds) than a 12 gauge (around 8 pounds typically) as well as being slightly more powerful.
|Gauge||Bore Diameter or Calibre|
Although the dimensions of 50 caliber rounds vary depending on the type (i.e. “ball,” “match,” “armor-piercing,” etc.), the typical 50 caliber bullet is . 510″ in diameter by 2.27″ in length, the case is 3.9″ in length, and the overall length of the assembled round is 5.425″.
|Parent case||.300 Remington Ultra Magnum|
|Case type||Rebated rim, bottlenecked|
|Bullet diameter||7.21 mm (.2840 in)|
|Neck diameter||8.1 mm (.320 in)|
They aren’t banned. Shotguns are still used in the military but their role has been limited because they have such short range uses. In WW1 shotguns primarily could only be used at very close range to clear out trenches of enemy soldiers.
410-bore shotgun is the only exception to the gauge designation for shotguns. It has an actual bore diameter of 410/1000ths of an inch, which is approximately equivalent to a 67½ gauge.
A door made from 10-gauge (. 135) steel is over twice as strong as one made from 12-gauge (. 106) steel even though it is only . 029 thicker (see Steel Strength Chart).
Sawed off shotguns can be especially deadly because the ammunition is propelled faster than it would be if the barrel was complete. … In the United States, it is illegal to posses a sawed off shotgun that has a barrel length of less than eighteen inches, unless the individual has obtained a taxed permit from the ATF.
A shotgun is a firearm subject to the NFA if the shotgun has a barrel or barrels of less than 18 inches in length. A weapon made from a shotgun is also a firearm subject to the NFA if the weapon as modified has an overall length of less than 26 inches or a barrel or barrels of less than 18 inches in length.
At close range, 20 gauge buckshot is typically just as effective as 12 gauge, but it can have a lot less recoil. Less recoil usually leads to better shot placement, and for a lot of people, it also means they are more likely to practice.
There is no such thing as a 22 gauge shotgun. There are both rimfire & centerfire 22 caliber cartridges, and even shot cartridges available for 22 rimfire-both 22 LR & 22 magnum. A gauge in shotgun definition means the number of round lead balls of that bore size that makes 1 pound.
12 gauge shotgun
12 gauge diameter
12 gauge ammo
12 gauge in mm
gauge to caliber chart
12 gauge thickness
10 gauge diameter
12 gauge slug