Them!

The weapons seen in this 1954 movie are:

M20 "Super Bazooka" (3.5" Rocket)

Used Sgt. Ben Peterson (James Whitmore) and Major Kibbee (Sean McClory).

M20 "Super Bazooka" 3.5"

Peterson, enjoying himself a little too much, takes aim.

Another bazooka used by Kibbee.

M1 Flamethrower

Peterson wears an M1 Flamethrower accompanying Pat and Graham into the nest.

Schematical drawing of M1A1 Flamethrower

Peterson (right) wearing the flamethrower as the group enters the nest.

Peterson roasts a giant ant that comes out of the wall.

Peterson prepares to torch the queen's chamber.

M1928 Thompson

After his service revolver fails to slay the giant ant, Peterson runs and gets this from his patrol car. Needless to say it packs a bit more of a punch. Agent Graham and several soldiers use them in later scenes as well.

M1928A1 Thompson with 30-round magazine and early 'simplified' rear sight that would be adopted for the M1 Thompson - .45 ACP

Peterson locks and loads.

Peterson gets medieval on the ant's abdomen.

Graham firing an M1928 Thompson with his eyes shut at the film's climax.

Blackburn's revolver

Doomed redshirt Trooper Ed Blackburn (Chris Drake) uses this revolver.

Blackburn unholsters his weapon and turns the light out so the unknown assailant (unknown to him, a giant ant) won't see him emerging from the room.

Blackburn prepares to meet his maker courtesy of giant mandibles.

Colt Official Police

Trooper Sgt. Ben Peterson (James Whitmore) uses this holstered Colt Official Police to shoot at a giant ant.

Peterson shoots at the ant.

Peterson comes to the conclusion his service revolver isn't doing much good.

Colt Official Police with 4 in. barrel.Nice screencaps,by the way.

• Thanks.

Graham's revolver

FBI Agent Robert Graham (James Arness) shoots at an ant with a small snub-nosed (?) revolver.

Graham is told by an offscreen Dr. Medford to go for the antennae.

He does precisely that.

Appears to be a Colt Detective Special.

Snub-nosed revolver

A snub-nosed revolver is found by Sgt. Peterson in the destroyed camper at the beginning of the movie.

The revolver lying on the floor.

Sliding a pencil into the barrel, Peterson picks the revolver up to examine it.

Lever-action rifle

A lever-action rifle, described as a 30-30, is found at Gramps Johnson's store with the barrel bent in half.

The rifle lying on the floor.

Peterson examines the weapon as Blackburn looks on.

Captain Edwards examines the gun.

Unknown rifles

The soldiers at the film's climax use these rifles in addition to the Thompsons.

Two soldiers take aim with their rifles.

More rifles including two grenade-firing ones.