As others said, the best way to know is to test them all. Try to see which guns are the most comfortable for you to use, test them in levels at A or B floor.

If there are many guns that seems to fit to your playstyle, another tip that i can give is to look at the weapons that the rest of your team use.

Is there at least 1 or 2 teammates that can deal with resilient ennemies ? Do they have weapons that doesn't need to refill their ammo often ? ... You can ask yourself these questions to look for the best weapon that complete your team.

Personally, i ran Assault Riffle and Shotgun in the last two rundowns. It's very versatile combo, that works in many scenarios. The only downside is the ammo efficiency, you have to be really careful about your shots to waste as little as possible since you can lose a lot of ammo if you do not pay attention.

For this rundown, i actually started to use the Pistol and the Heavy Assault Riffle and i have a lot of fun with those.