The match structure of an Arms Race game takes place in a single round with no time limit. At match start, all players spawn with the same weapon and will respawn instantly on death. Players are invulnerable after spawning and will stay invulnerable for a short time unless they fire their weapon.
The goal of the mode is to RACE the other players to the highest level weapon and get a kill. To reach the highest level, players must upgrade their weapons by progressing through weapon levels by eliminating players on the other team.
The last weapon in the progression is the Golden Knife. The match ends when one person kills an enemy with the Golden Knife.
To acquire a new weapon, you must increase your weapon level. There are three ways to increase your weapon level.
Get 2 kills with your current weapon.
Kill the enemy team leader (unless YOU are a leader).
Kill an enemy with your standard knife.
Both methods will instantly increase your level and grant you the next weapon in the list.
To see what weapon you will upgrade to when you progress to the next level, you can view the progress panel on the right side of your HUD, above your ammo count.
The progress panel also shows how far away you are from the final level with the dotted progress bar on the very right.
The weapon list is random for each match, but the category order is always the same. Each player will have to get 2 kills with each weapon type in the following order.
2 Sniper Riles
1 Machine Gun
You can view your ammo panel in the lower right of your HUD to see how many kills you need to perform before you upgrade to the next weapon level. Unfulfilled kills are shown as a hollow kill pip outline.
Team leaders are the players who have the highest weapon level on each team.
You can see all player's weapon levels by looking at the Mini Scoreboard at the top of the HUD. A player's numeric weapon level displays below their avatar.
Additionally, team leaders will have a colored outline around their avatar in the Mini Scoreboard. Your avatar will be outlined in white.
If you become team leader, you will begin to glow and will be visible to everyone for a short time after you fire your weapon. If you don't fire your weapon for a bit, your glow will fade.
Killing the enemy team leader will instantly increase your weapon level. If you are the team leader, you will not see the enemy leader glowing, nor will you get the bonus for killing them.
How to Win
Arms Race can only have one winner and it's the player who get's a kill with the Golden Knife. To get the Golden Knife, you must successfully progress from your initially assigned weapon to weapon level 16.
Adjust to your weapon
Adjust your play style to the weapon you are currently holding. It may not be a good idea to run out in the open with a shotgun or go close quarters with a sniper rifle. If you are having a hard time getting a kill with a certain weapon, try adjusting your play style a bit or trying a different tactic.
Go for the enemy leader
Killing the enemy leader will upgrade your weapon level immediately (unless you are a leader yourself). You can progress levels faster by going after the leader.
Don't go for the enemy leader
Wait, didn't you just say....? Yes, but sometimes going for the enemy leader is not the best option. If you already have one kill with a weapon, killing the enemy leader is no different than killing anyone else. In this case, go for the easiest and quickest kill (which may not always be the leader).
Additionally, always going for the enemy leader may cost you precious time. Remember, this is a race and progressing the fastest is the best strategy. If the leader is frequently across the level from you, it might be more costly (and possibly more dangerous) to always go for them. Stay smart and choose your enemies wisely.
De-Level your enemies
Killing an enemy with your regular knife will cause them to lose a weapon level. If you have the opportunity to stab an enemy in the back, go for it!