Kamen Rider X

The following guns were used in the movie Kamen Rider X:

Pistols

M1911A1

In X-X-X-Rider is Born!!, a GOD soldier disguised as a human brandishes a M1911A1 at Jin Keisuke after arriving in Tokyo by ship. Jin is also shot to death by several M1911A1s in the same episode.

A Human disguised GOD soldier shows Jin they mean business.

Submachine Guns

MP40

In Episode 5, The One-Eyed Monster's Human Review Operation!, a GOD soldier is armed with the MP40.

GOD soldier with the MP40 in the underground base.

Uzi

A GOD soldier has an Uzi in Episode 6, The Japanese Islands Fragmentation Plan!. In this episode, it has a wooden stock.

A GOD soldier's Uzi barrel aimed at Jin and Tobei.

Uzi Carbine

GOD soldiers use the Uzi Carbine as their main weapon as seen in Episode 5.

Clear photo of where the magazine should be inserted. Unfortunately, there's none.

It's hard to see, but the Uzi Carbine barrel can be in adjacent to the soldier's goggles.

Jin Keisuke choking a GOD soldier. You can see the Uzi stock, trigger grip and body.