Generally speaking no felon (regardless of their age) is allowed to possess a firearm.
Blue Book of Gun Values
Six factors.
The Gun Digest Book of Modern Gun Values, 9th ed, shows the Stevens No.66 with a used value of $75 to $80.
Archimedes died at about age 75.
Receiver
he died at age 75.
75-100 years ago
75-300 USD
75-275 or so
IQ is not dependent on age. Regardless of age, a person who possessed an IQ of 75 would be Mildly Retarded, or very close to that.
The French "75" was a howitzer, a large gun used for firing in a high arc onto the enemy. The French 75 was a huge leap in technology of large guns, as it used a hydraulic mechanism to use the recoil of the gun to work the action, and also made the recoil of the gun less. This allowed the French 75 to fire at a much greater rate than contemporary guns.
The age of a Springfield model 83 .22 caliber single shot rifle is between 75 and 79 years old. The guns were manufactured by Stevens Arms Company between 1935 and 1939. Depending on the condition of the gun they may be sold for anywhere from $40 up to about $75.