That's a very interesting box...
I THINK, based on things I know about the Super X line and some quick and dirty research I did on line, that that particular box can be narrowed down to a VERY tight time frame... 1946 to 1948.
That's very unusual because it's often impossible to get a tight focus on the date unless you have actual purchase records or you're able to get lot number info from the manufacturer.
Here's why I think it's 1946 to 1948...
The first clue is the "Super Seal Cup Wad," which came into use in 1946 or 1947.
The other clue is "Rolled Crimp." Western quit using rolled crimps and over shot wads in 1947 to 1948, and adopted star crimps, which they called the Super Seal Crimp, and which would have been printed on the box in place of the Rolled Crimp text.
The fact that the box is full works in your favor.
The box isn't in great shape, though, so that's a minus.
All told, though, that box of shells is probably worth between $25 and $50.
These days shotshells have been standardized at 2 3/4" and 3" for 20, 16, and 12 gauge.
That really came about in the years right after WW II, although the movement had been on for some years before that.
Prior to World War II, and especially prior to WW I, shotshells were widely varied lengths.
The old industry "standard" lengths were:
12 gauge - 2 5/8"
16 gauge - 2 9/16"
20 gauge - 2 1/2"
They became the "standard" lengths only because most of the major manufacturers adopted those lengths.
Prior to that there was a WIDE range of lengths, with just about every big gun maker doing their own thing.
I THINK the 16 gauge 2 9/16" became the standard because Winchester either introduced it or adopted it.