I think the gun porn is way overboard. I really don't care that there are two different lengths for 7.62mm ammo and I get pissed when I accidently buy the wrong one.
Anyways, I used this post to keep me sane with all the gun selections:
http://www.ja-galaxy-forum.com/board/ubbthreads.php?ubb=showflat&Number=199401&page=1
Agreed, I'll be the first to admit that ammunition sizes are a problem, but that stems from the same real life issues that exist and if you're building a game off of real life items, you can't really simplify things too much without causing other problems or just getting away from the realism you were searching for in the beginning.
Ammunition really lacks any sort of standardization in their labeling or measurement procedures, as a couple of quick examples. 9mmx19 ammuntion is also called in various places, 9mm Luger, 9mm Parabellum and occasionally 9mm NATO or some variation of combination of those terms. You've also got the .38(in inches) Special ammunition and the .357 Magnum Ammunition which are the exact same diameter, but because they're measured differently are labelled as different measurements. (In fact it's fairly common to fire .38 Special from .357 Magnum revolvers as a cheaper alternative while practicing, although it's generally bad practice to fire ammo from a gun it's not designed for and I don't condone or suggest it.)
A quick look at the
wikipedia lists of the various firearm calibers out there makes it clear that despite the confusion that can occur in JA2, it's really kept things fairly simple. There have even been a few instances in there where, even as an amateur, I've realized that they've taken steps to keep things simple and given guns cartridges which were slightly out of line(or at least shouldn't be interchangable with the other weapons that use it in game) with the real deal.
Personally, to keep things simple, I like standardization, as much as possible. At the very least my first step is to get everyone the same caliber pistol, and once assault rifles start showing up, I try to do the same there. Sniper and other special weapons are more tricky, and I usually just take them as they come and deal with ammo issues occasionally. This does, on the other hand, mean you'll be wasting a lot of ammo that's not your choice of standardization(example, I usually pick 9x19mm pistols and end up with a lot of useless 9x18mm ammo)
But yeah, point is, don't blame JA2, or even 1.13, they didn't have a hand in these naming schemes, they've taken steps to make it easier on you and there's not much they can do beyond that than simply go the bare bones "pistol ammo" "rifle ammo" route or make everything weapon specific and make it so that, no, you can't take the cartridges out of your Thompson SMG and put them into your M1911 Pistol, despite the fact that realistically you could. As for too many Weapons... feel free to ignore most of them and play around with anything that looks interesting. Only thing I'd suggest is despite the history and reputation of the AK-47, stay away from that specific model and stick with one of the more recent variants of it if you want to go that route, assuming you have a choice. They all have minor little differences, but they're almost universally better than the original.