do all shotguns shoot magnums or not? Should it be stamped on the barrel if it does?

They will all shoot "Mag" dram shells. Unless the barrels are made of damascus (twist) steel. In which case you should not fire the gun without first seeing a gunsmith to have it checked out, and still not shoot mags out of it.

What sort of firearm to do you have? Anything in particular you can tell us?

Stamped on the barrel will be a chamber length. General rule is guns can shoot shorter shells than listed, but not longer than. For example, your barrel may read, for 3" or shorter shells, which means you can shoot ANY 2 3/4" or 3" shell in that gauge. That includes "magnums", as long as they do not exceed the length stamped on the barrel.

magnum, and max shells, one relates to the greatest power load....the other greatest amount of shot. I think max is most shot, magnum is most powder.

We don't use actual drams of powder any more. Dram measurements were used with black powder. However, the word"dram" is still used to describe the velocity that you can get from any given shot shell load.

What all this means is this... Back when drams ofblack powderwere usedit was measured in drams. "X" drams produced "X" velocity with "X" amount of shot.Modern smokeless powder that produces "X" velocity with "X" amount of shot is listed with the same "dram" rating as was used with black powder cartridges.

Basically all this dram stuff is just a modern equivalant velocity rating with any given weight of shot.

Sort of... you are barkin up the right tree. One relates to powder (mag), one relates to SAMMI pressures (max) with respect to powder/shot. But they are both tied together.

Essentially they just did it to confuse the hell out of everyone.

Toros grande is correct.

The reference charge they used was a 3 dram of black powder with 1 1/8oz shot which gave a velocity of 1200fps. So when you see a target 12ga load that reads across the box: 12 1 1/8 3 8 that means you have a 12ga with 1 1/8oz shot, going 1200 fps, size #8 shot. Most companies now just list the fps, which makes a lot more sense to me. Some list both. The MAX loads depend entirely upon the shot charge... you can get MAX loads in 1 1/4oz or 2 1/4oz in a 12ga 3.5" shell.

I haven't bought a box of shotshells for so long it's pitiful. But I think I remember that when the term Dram was used, it was printed "dram equiv." on the box. It was always my understanding that it meant the amount of smokeless powder loaded in that shell had the equivalent of that much black powder (3 3/4 drams, for example),that it took to achieve a certain velocity, but it is definitely NOT on a weight-to-weight basis.

I can tell you one thing, 3" magnum shells loaded with 00 buck shot kick like crazy!

Read the barrel, it will tell you exactly what to shoot. 3" Mag or both, or it will read 2 3/4" only.

OK Guys Maginum relates to the shot charge maximum IS the powder charge . As a guide 1 1/8 oz is standard at 1 1/4 Most are labled mag . NOT all 3" 12 ga are magnums .
To my knowledge excepting the 3 1/2 only the autos specify mag or not .