Generally speaking no felon (regardless of their age) is allowed to possess a firearm.
Six factors.
Blue Book of Gun Values
Archimedes died at about age 75.
The Gun Digest Book of Modern Gun Values, 9th ed, shows the Stevens No.66 with a used value of $75 to $80.
Receiver
he died at age 75.
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.
75-275 or so
75-100 years ago
75-300 USD
75
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.