This text is in regards to if a new gun is added to the game.

I see a gun that has projectile ammunition. Its bullets take time to reach their target. It does no splash damage, it just fires regular bullets. The thing is, they're projectile.
Give it a MASSIVE magazine size.
Make its bullets fairly weak, make the bullets not do too much damage.

So a gun that has a massive magazine, that fires projectile ammunition, that doesn't do too much damage.
The strategy is to play on the gun's strength, which is the amount of time you have between reloads to fire the weapon at an opponent. Also, because of the projectile nature of the gun's bullets, you can pre-fire at an entryway before an enemy appears and the enemy will run into what you have fired after you have fired it. You will have plenty of opportunities to do this because of the massive magazine size.

It would likely be a medium range weapon. Medium damage because I like using weaponry that isn't "the best" or overpowered, often requiring strategy to employ effectively. I think it adds character to the game.
Also, something about firing ahead of the target in order to land shots is fun to me.