Six-gun and Shooting iron

Six-gun noun - A pistol with a revolving cylinder (usually having six chambers for bullets).

Shooting iron and six-gun are semantically related. In some cases you can use "Shooting iron" instead a noun phrase "Six-gun".

Shooting iron noun - A firearm that is held and fired with one hand.

Six-gun and shooting iron are semantically related. Sometimes you can replace phrase "Six-gun" with "Shooting iron", this phrases are similar.