stupid question

[Lucky Scott]

I googled and cant find answer, perhaps it is too basic of a question.

I got a 4X32 scope on my rifle. I measured the scope and it is 1 and a half inches across, so where is the 32 come in? How do I compare the 32 to a 40 or whatever? Is it a optical number rather than a size number?

How much bigger is a 40 in inches?

What works best on a big caliber rifle than is just target shooting at 100 to 300 yards?

[sevensix2x51]

the 32 is called "effective lens diameter," basically how big that front lens is; in millimeters.

the larger the lens, the more light it will gather. it doesnt necesarily mean it is any more accurate. (basically)

[Lucky Scott]

Thanks