"The Colt" (Colt Paterson 1836 cartridge conversion)
"Back in 1835, when Halley's Comet was overhead, same night those men died at the Alamo, they say Samuel Colt made a gun. A special gun. He made it for a hunter. A man like us, only on horseback. Story goes, he made thirteen bullets. This hunter used the gun a half dozen times before he disappeared, the gun along with him... Somehow Daniel got his hands on it. They say... they say this gun can kill anything."
The pistol which is simply referred to as "The Colt" is a modified Colt Paterson 1836, first seen in Season 1. The actual gun appears to be built from a Pietta "Paterson Extra Deluxe" based on the engravings and silver inlay markings. The pistol is further modified with a cartridge conversion, by having a pentagram carved into each grip plate, and the barrel is engraved with "non timebo mala" which translates to "I will fear no evil" (a reference to Psalm 23).
Taurus Model 689
Ellen Harvelle (Samantha Ferris) uses a Taurus Model 689 revolver with blued finish a wood grips in "Good God, Y'all" (S05E02).
Taurus 65
Janice (Lucie Guest) uses a stainless steel Taurus 65 in "My Bloody Valentine" (S05E14).
A sawed off Ithaca 37 is used by the brothers on several occasions, most commonly by Sam (Jared Padalecki). It is often used with rock salt shells, which are depicted as being effective against some supernatural beings such as ghosts and demons.
Unidentified Shotgun
An unidentified shotgun with a heat-shield, full length magazine tube and a pump with an integrated flashlight can be seen in the weapons compartment in the trunk of the Impala. It is not the Remington 870 seen in previous season as noted by its heat-shield and shorter barrel/magazine tube.
Franchi PA3
A Franchi PA3 is carried by Rufus Turner (Steven Williams) in "Good God, Y'all" (S05E02). A PA3 is also used by Pastor David Gideon (Larry Poindexter) in "99 Problems" (S05E17).
Coach Gun
A Coach Gun with particularly short barrels is carried by Jo Harvelle (Alona Tal) in "Good God, Y'all" (S05E02). It doesn't appear to be sawed off but rather a production weapon, as the barrels appear properly finished and a sighting bead is present, which would not be the case with most sawed off weapons.
Over and Under Shotgun
An Over and Under Shotgun is used by several of the surviving townspeople in "Good God, Y'all" (S05E02).
Remington 870 (Wood Furniture)
Remington 870s with wood furniture appear in several episodes.
Remington 870 Slug Gun
Remington 870 Slug Guns appear in several episodes, either with standard length or extended magazine tubes.
Hawk 372
Several characters use Hawk 372 shotguns with the heat-shields removed in "The End" (S05E04).
Valtro PM5
A Valtro PM5 with a 14" barrel is among the weapons used by the group of hunters in "The End" (S04E05).
Winchester Model 1887
A sawed off Winchester Model 1887 can originally be seen being used by Jo Harvelle (Alona Tal) in "Abandon All Hope..." (S05E10). After she gives it to Dean (Jensen Ackles) during that episode, it becomes his main shotgun replacing his sawed off double barrel shotgun.
Special
Jensen Ackles can be seen shooting a Winchester Model 1887 at a shooting range with a sawed off stock but a longer barrel during the "Gag Reel" special feature on the DVD.
An unidentified bolt action rifle is used by several of the surviving townspeople in "Good God, Y'all" (S05E02).
M16A4
An M16A4 fitted with a telescopic sight is used by Austin (Shawn Roberts) in "Good God, Y'all" (S05E02). Close ups of the lower receiver reveal that it is actually a semi-automatic only sporting rifle manufactured by Dlask Arms Corp., a Canadian company.
Jo Harvelle (Alona Tal) can briefly be seen loading a Remington Model 7600 with a telescopic sight in "Good God, Y'all" (S05E02).
Browning BLR 81
Browning BLR 81s are used by several of the surviving townspeople in "Good God, Y'all" (S05E02).
M4A1
US Soldiers can be seen with M4A1s in "The End" (S05E04).
M16A2
The future version of Dean (Jensen Ackles) can be seen with what appears to be an M16A2 in "The End" (S05E04). The round handguard is visible, however the receiver is not shown in detail so this ID is not conclusive.
Heckler & Koch SL8-4
One of the hunters (Dwayne Bryshun) who is following the future version of Dean in "The End" (S05E04) uses a Heckler & Koch SL8-4 fitted with a suppressor, bipod and telescopic sight.
Other Weapons
MilTec G1 Paintball Pistol
A MilTec G1 paintball pistol is one of the many weapons in the weapons compartment of the Impala.
Tranquilizer Pistol
A nickel plated tranquilizer pistol is used by Trevor (Alex Arsenault) in "Swap Meat" (S05E12).