Roblox Weaponry

Building Weapons in Roblox: What Actually Works

Most people building weapons for Roblox games run into the same wall within the first hour. They script the hit detection on the client, it works perfectly for them in testing, and then multiplayer reveals the problem instantly. I spent about three months working through this properly on a project last year before getting something solid.

The core issue with Roblox Weaponry is that Roblox is a client-server architecture by default, and weapons sit squarely in the middle of that divide. You have to decide who calculates damage, who validates hits, and who applies the result. Get that wrong and you either get exploiters deleting every player in range or your gun not firing at all past 40 studs. Here is how it actually works when you get it right. The client detects the hit using Raycasting or an area check, sends a remote event to the server with the target's position and the direction of fire, and the server validates everything before applying damage. The server does the heavy lifting because it can't be trusted to do otherwise. This adds about 10-30 milliseconds of latency depending on your server location, which means your hit registration will always feel slightly behind what the player sees. I ran into a specific edge case with one of my projects where players using high-ping connections were getting double damage on their shots. The problem was that I was firing the remote event from both a local script and a server script simultaneously during reload transitions. The fix was wrapping the damage call in a debounce that checked whether the server had already processed that specific projectile's hit event, using a unique ID stored in a dictionary keyed by the projectile instance. Cuts the issue down to zero, adds maybe five lines of code.

Raycasting vs. Projectile Physics

There are two main approaches and picking the wrong one ruins your game. Raycasting is instant, cheap, and works for everything from pistols to snipers. You shoot a ray from the gun's barrel point forward, check what it hits, and deal damage. The server version looks like this: Projectile physics look better visually but cost significantly more. You spawn a actual object, move it each frame, and check collisions. Every projectile you spawn uses memory and processes every frame until it hits something or is destroyed. A typical combat game with eight players and three projectiles each running at 60fps means your server is doing 144 physics calculations per second just for weapons. That adds up fast if you're also doing movement, building, and other systems. I switched most of my weapons to raycasting after benchmarking. The visual difference for players is basically nothing unless you're specifically aiming for a game that looks like Halo. The performance difference is between 2ms and 18ms of server frame time per shot. That is the kind of gap that determines whether your game runs smooth or chokes during a big fight.

Why Predictive Client-Side Hits Kill Your Game

Every beginner tries to make the client apply damage immediately so the shooter feels responsive. This feels good until an exploiter starts sending remote events with invalid target positions or shoots through walls. I saw a game once where the developer had client-side damage with zero server validation and within two days of public release there were three separate exploit scripts circulating on a Discord with millions of downloads. The weapon did 999 damage and ignored cover entirely. The workaround most people don't think of is server reconciliation with rollback. The client predicts the hit and shows feedback immediately. The server validates. If the server says the hit was invalid, you revert the damage and adjust the player's health back to what it should be. It adds complexity but it is the only real solution if you want anti-exploit protection without sacrificing feel.

Common Pitfalls That Waste Days

One thing nobody warns you about is the PrimaryPart problem. When a character dies and respawns, the old character model is removed and a new one is created. If your weapon system is holding a reference to the old character's PrimaryPart, your next shot will silently fail because you're raycasting from a nil position. Always pull the PrimaryPart fresh each time rather than caching it. This cost me about four hours of debugging on my first weapon system because the errors never appeared in the output log. Another issue is server lag compensation. If your server is running at 20fps, a player's position from three frames ago could be 15 studs away from where they currently are. A raycast aimed at their reported position will miss. The standard fix is to store recent position history for each player and interpolate where they likely were at the time of the shot. Most people skip this and just accept that their weapons feel inaccurate on laggy servers. If accuracy matters for your game type, it takes about two hours to implement properly. The reality is that Roblox Weaponry is less about making guns that look cool and more about getting the networking model right. Start with server-authoritative raycasting, add client prediction only after the server side is working cleanly, and test with at least three different connection speeds before you consider anything done. I recommend using the Network Profiler built into Roblox Studio to watch your remote event traffic during testing. You will find problems you did not know existed within the first ten minutes of turning it on.