In Oklahoma, individuals are generally allowed to purchase and possess most types of firearms, including handguns, rifles, and shotguns. However, there are some exceptions to this general rule, and there are certain types of firearms that are prohibited by law. Class III weapons, such as short barrel rifles and shotguns, full auto weapons, called machine guns, and suppressors, called silencers are prohibited in Oklahoma without a federal tax stamp.

One of the main restrictions on the types of firearms that can be purchased and possessed in Oklahoma relates to full auto assault weapons. The state prohibits the sale, transfer, or possession of any semi-automatic rifle that has been modified to fire more than one shot with the single press of the trigger without a federal class III tax stamp. 

Another restriction on the types of firearms that can be purchased and possessed in Oklahoma is the prohibition on suppressed firearms. It is illegal to possess any firearm that has been modified to be have a sound suppressor or silencer, or to sell, transfer, or manufacture such a firearm. This includes suppressed machine guns, as well as any other type of firearm that is silenced or suppressed so as to affect the sound signature of the firearm.

In addition to these specific restrictions, it is important to note that it is illegal to purchase or possess a firearm if you are a convicted felon or have been committed to a mental institution. It is also illegal to possess a firearm in certain locations, such as schools, courthouses, and certain government buildings.

Overall, while Oklahoma generally has a friendly approach to gun ownership, there are still restrictions on the types of firearms that can be purchased and possessed in the state. It is important for individuals to understand these restrictions and comply with them in order to exercise their rights responsibly and legally.