The Mist is the limited televison series adaptation of the horror novella of the same name written by Stephen King. The series premiered in the US on SPIKE on June 22, 2017 and aired 10 episodes until August 24th, 2017. The Stephen King novel had previously been adapted into a 2007 feature film that was directed by Frank Darabont and starred Thomas Jane.
The following weapons were used in the television series The Mist:
Eve Copeland (Alyssa Sutherland) handles what appears to be a Walther P99AS taken from a throughout most of the episodes starting with "Withdrawl" (S1E02). In reality the gun used in the show is an airsoft replica of the Walther.
Glock 34
Kevin Copeland (Morgan Spector) handles an Glock 34 with a Glock 18-styled fire selector at the police station in "Pilot" (S1E01). In the same episode, Mia also uses the handgun. He however loses the gun in "Withdrawl" (S1E02) during the car crash.
The gun is, in reality, a fictional airsoft Glock model - likely either a Tokyo Marui or WE-Tech G35. No select-fire Glocks with long barrels are known to have been produced in reality, and even if one did, it is much more likely that the production company simply used an airsoft replica.
SIG-Sauer P226 (nickel)
A man who threatens Mia and her group is armed with a nickel SIG-Sauer P226 in "Withdrawl" (S1E02).
The Glock 17 is seen in the hands of the police officers as well as the survivors who are at the police station. It is first seen in the episode "Withdrawl" (S1E02).
Shotguns
Benelli M3 Super 90
A police officer is seen taking a Benelli M3 Super 90 shotgun from a locker in "Pilot" (S1E01). In "Withdrawal" (S1E02), Jonah Dixon (Okezie Morro) has a Benelli slung over his shoulder.
Mossberg 500AT
In "The Law of Nature" (S1E08), Adrian Garff (Russell Posner) uses a Mossberg 500AT and Kevin Copeland (Morgan Spector) briefly handles the Mossberg. Jonah Dixon (Okezie Morro) handles the Mossberg in "The Tenth Meal" (S1E10).
Over and Under Shotgun
The man who appears to be a soldier at a house Kevin and Vic take refuge in can be seen with an Over and Under Shotgun in "The Waking Dream" (S1E09).
Rifles/Carbines
Colt M4A1
Some of the soldiers at the end of "The Tenth Meal" (S1E10) appear to be armed with M4A1 carbines.