Not necessarily. I have plenty of real world military background of my own to draw on. For example, your average shotgun is about the same weight as an assault rifle and has similar dimensions except that they will typically be a few inches longer in the barrel.
Which I stated.
If you expect to have me buy that a shotgun must use a heavy weapon mount? I'm sorry I just don't buy it.
Actually, I'm saying that a shotgun goes into a standard mount - not sure why you think otherwise.
A sniper rifle is also going to have similar weight and dimensions except for length and I don't necessarily see that requires the necessity of a heavy mount there either.
Well, if you consider 10 inches and 2 or 3 pounds to be insignificant, then your military experience may not have involved ruck marches.
Length is but one dimension to measure by. Measure by a different method (width, depth, mass or volume) and you could end up with a different result.
Except that when all other things are the same, or similar enough (and they're not terribly far off from each other, with a few exceptions for high-caliber sniper rifles like a Barrett) length is still wildly different between shotguns and sniper rifles. And between assault rifles and sniper rifles. But not between shotguns and assault rifles, as they're about the same size. Again, I talked about this part.
There is a extremely simple method to determine what weapon goes on what mount and that is by putting heavy weapons on heavy weapon mounts and putting all other weapons on standard mounts. I just don't see justification in the rules for making it more complicated than that.
You could start with the rules, which state that the difference is that a standard mount holds "assault rifle or smaller-sized weapon". Since the rules state that size is the determining factor, and since most of the other factors of size are roughly the same (again, with the rare exception) length is the only factor that is wildly different.
I've stated all this like... four times now. The only reason for your arguments are because either you didn't read the rest of the posts in this thread, or you're trying to keep an argument going unnecessarily.
Fact: sniper rifles are longer and generally a little heavier than assault rifles.
Fact: shotguns are very nearly the same length and weight of an assault rifle.
Fact: the rules state to go by size when determining what can go on what mounting system.
Fact: unless we hear otherwise, the only logical outcome of the "assault rifle or smaller-sized weapon" quote is that a heavy mount can mount any weapon, including all heavy weapons and sniper rifles. A standard mount can hold anything BUT a sniper rifle or a heavy weapon.
Exactly my point
Except that your "point" flies in the face of the rules completely. It might be that it's simpler to say "heavy weapon == heavy mount." But the book doesn't say that, which means it's a house rule at best. If you guys want to talk about a house rule, then by all means go ahead. Those of us that play the game by the rules will have to politely ask that you move your discussion to a house rule thread instead. It's confusing the question that the OP and other people might have about what the book actually says.