According to Wikipedia, rifling was invented in the late 15th century by one Jaspard Zoller in Vienna and improved by August Kotter in Nuremberg. This statement was not given any reference supporting it.
I had read in several places over the years that rifling was invented somewhere in Switzerland during the 15th century, but it was not known who the inventor was.
Standard
Length, rifling (sometimes)
Rifling in the barrels
Rifling was invented in the late 15th century. It was improved by August Kotter of Nuremberg in 1520 and by others later. There is a link below.
Muskets have smooth bores and rifles have rifling - spiral grooves to make the bullet spin. Rifles have longer range and better accuracy. Both were originally muzzleloaders, but rifles eventually began to use metallic cartridges.
If you are asking when the first guns were made they were first made in China during the 13th century for use as a signal. Springfield rifles were among the the first breech loading rifles in1865.
AnswerAugust Kotter invented the rifle in 1520. The 16th century.
Rifles have spiral grooves cut into the inside of the barrel, known as rifling. Muskets are smoothbore. Rifling causes the bullet to spin in flight, permitting accuracy at long ranges. Also slower to load.
The origins of rifling are difficult to trace, but some of the earliest practical experiments seem to have occurred in Europe during the 15th century.
ALL rifles have barrels that contain "rifling". This is usually in the form of spiral grooves cut into the inside of the barrel- a few have a non-round barrel, with flat surfaces that twist as you go up the barrel. At one time, ALL shotguns had smooth bores- no rifling. However, SOME shotguns now have barrels with rifling, used to shoot slugs. They are still not rifles, as they are meant to shoot shotgun shells.
Octagan
This was a term used for certain US military rifles- the bores were checked using a special guage. Rifles that were found to have a high degree of uniformity to the rifling were marked at the muzzle with a star. Today, these might be known as "Match" quality.