Pick a gun:
- Aim down sight and simulate a combat without firing. That will tell you if you like the aiming.
- Pick a target and shoot at it to test recoil.
- Finally, to find out the damage, look at how deep goes the projectiles.

In the end, you will find the weapon that fit you most.

Originally posted by Hylobates Lar:

Which guns are worth taking?

In early game, I recommend using something that the insurgents carry a lot of ammo and mags for. In one playthrough, I found a really nice Simonov (AK74-like) with all attachments. Other good options would be one of the 12ga shotguns, one of the bolt action snipers and of course any of the sidearms they carry.
This way you'll never be wanting for ammo or spare mags. There's nothing worse than getting caught with all empty mags in a really dangerous moment, I always try to keep a few loaded and ready.

Later on, you might find rare weapons like a 50BMG. I would definitely keep those, any way you can. I've never tried this but you might be able to weld the weapon to the inside of your car, if it's too bulky to fit in your inventory, and then you can pick it up again whenever you need. Definitely experiment with that first because I've never tried it.
I would say keep those because they're probably excellent for boss enemies and tanks.

Originally posted by Hylobates Lar:

which are best off leaving?

See, this might just be the way that I play, but I have a hard time leaving anything behind. If your vehicle has room in the trunk, back seat, personnel area etc it's in your best interest to chuck that ♥♥♥♥ in your car and forget about it, then move on and sell it when you find a merchant.

If you absolutely have no room to take extra guns and stuff, my recommendation is to leave behind any guns at your current tier or lower. If you have a Simonov with all attachments and insurgents are dropping vanilla Simonovs, just leave those behind. Similar for if you have a semi-auto 12ga and all you're finding are double barrels, so on and so forth.

I hope that helps. If you found this information useful, can you maybe have a look at my discussion post about saving not working? I'm trying to get a dev to see it, I can't tell if I'm doing something wrong.

I use a big trailer truck, and I just toss everything in the back. I also put a little jeep inside, using the trailer ramp. To store my gas cans, I cut a hole in the side of the cab behind the drivers seat and toss the cans in there so they don't fall out. I also weld various structural stuff to the front of the cab as improvised armor, like concrete barriers on the front and sections of wire fencing on the sides.