At the end of Archer Dreamland: Gramercy, Halberd! (2017), everybody in the car was out of ammo, so Archer had to jam the halberd into the front wheel of Dutch's motorcycle to crash it. Now, suddenly Archer has a loaded gun. (Granted, he could have just plain forgotten about the gun earlier, what with his brain all addled due to sleep deprivation and drug abuse.) However, as the whole series is a comatose dream, continuity is irrelevant since dreams don't follow the rules.)