The size of the bore.
Wiki User
∙ 14y ago12 has a bigger bore.
Size of bore, size of ammuntion
The 12 gage has a bigger barrel then a youth 20 gage shotgun.
20 gauge is larger
The metal of the 17 gauge waste drain is thicker than the 20 gauge.
12 Gauge is thicker then the 20 gauge.
12
12 gauge is thicker than 20 gauge. The lower the gauge, the thicker the sheet metal or wire.
There is no difference. A 500 is a basic Mossy 500 receiver shotgun. Unless the gauge is stated, it's assumed it's a 12. The 500A is simply stating it as a "12 gauge" 500 in its name. The Mossy 500A is a 12 gauge model 500, the 500B is a 16 gauge model 500, the 500C is a 20 gauge etc. There was no 28 gauge so there is no 500D, contrary to many sources, so the next one was the .410 called the 500E. A 12 gauge model 500 and a 500A are the same gun.