Difference between slugs and 3 inch magnum load?

[shooter43]

I was going through 3 boxes of shells for my 12 gauge I'll be using for deer season this year and found 4 slugs and a 3 inch magnum load. What is the difference between the two? Is the 3 inch just a name for buckshot? Is it powerful enough for deer in the first place?

 

[myfriendis410]

3 inch simply refers to the length of the shell. It has nothing to do with the payload. It could be #2 bird shot or a slug. If you can't figure out what it is then you should not use it.