Gun rules for sci-fi homebrew

The problem with automatic weapons is that you either get bogged down in the tedium of tracking bullets, with the advantage being a more realistic system, or you abstract the process a little bit.

For ammunition, lets take an automatic rifle as an example. I'd say the clip has 4 'rounds' - 4 single shots, 2 bursts, or 1 empty clip. Yes, it's kind of unrealistic to have single shots count for 1/4 of the clip, but on the other hand, this is a much simpler system to mentally track and is easier to balance for damage

For to-hit, the trade off is whether you make ammo abundant and make it harder to hit, or make ammo more scarce and give people the option of conserving shots vs. doing damage. Another trade off is whether or not you want standard damage, or deadly firearms (covered later) Let's assume the former: single shots can be made with +2, bursts as normal, and empty clip can be divided into arc fire or single target.

Against a single target, empty clip attacks would be made with disadvantage; in an arc, the shot would be a cone of X feet , resolved with one attack roll against each target's AC, the attack modified by -1.

For damage, if using a standard damage amount for 5e, I'd break it down like this: 1d4 for pistol single shots (light/finesse), 1d6 for autorifle single shots, 1d8 for autorifle bursts, 1d12 for empty clip (single target), 1d6 for arc fire.

If you're using deadly guns, you can either balance this by lowering ammo amounts and making attack rolls more difficult, or by putting more damage potential in the hands of the enemy. Keep in mind that the latter option will drastically change the style of play. Higher amounts of damage force both sides to get tactical, making full use of cover, flanking actions, etc. This is not necessarily a bad thing, just make sure that you set up your encounters appropriately.

/r/UnearthedArcana Thread