Cannon Vs Machine gun

The shape is inspired on the .50 because it was know these were already travelling into the sound barrier without any problem. Artillery guys were already doing faster than sound in the XIX century if I’m not mistaken.

PS: I just resized and rotate it keeping aspect ratio.

The shape is inspired on the .50 because it was know these were already travelling into the sound barrier without any problem. Artillery guys were already doing faster than sound in the XIX century if I’m not mistaken.

PS: I just resized and rotate it keeping aspect ratio.

Not far out really is it:)

The difference between a cannon and a machinegun is the calibre.

20mm and above = cannon

Below 20mm = machinegun

Atleast according to my military training.

Well the germans called it a machinegun although it often called a cannon in english texts , maybe becouse the MG151/20 was way more common.

The difference between a cannon and a machinegun is the calibre.

20mm and above = cannon

Below 20mm = machinegun

Atleast according to my military training.

Was the MG 151/15, as fitted in the early Me 109F’s, considered as a cannon or a heavy machinegun?

The differnece between a machinegun and a cannon is the amount of energy generated by their firing. Additionally the projectiles of a cannon are designed to carry an explosive payload as their primary purpose. Machingun ammunition is primarily of ball configuration (i.e. it’s inert). Obviously there are exceptions to the rule. As technology has progressed the use of explosive fillers in small arms ammunition (especially the 12.7X99 or .50 cal) has increased. Raufoss ammunition from Sweden for instance has an explosive filler of a gram of RDX HE.

Rate of fire was never considered as a determiner of MG or cannon. The M2 Browning in air mode (AN-M2) has a ROF of 750 to 850 rounds per minute. The M24A1 20mm cannon (as used in aircraft) has a ROF 750 to 800 rounds per minute. Not so much of a difference. The big difference is in projectile weight. A .50 cal has a projectile weight of approx 46.49 grams and the average 20mm projectile weighs in at 103.47 grams. Muzzle velocities for both weapons is about the same and the chamber pressures is likewise about the same at around 58,000psi. But the recoil force of the two weapons is vastly different. I don’t remember the exact amount but the 20mm has a recoil energy approximately 4-5 times that of a .50 calber MG.

Below is a collection of the rounds in question plus soem German rounds for comparison. From left to right is the American 20mm then the .50 cal then the venerable .303 British rifle round followed by the German 20mm and the 13mm from the MG 131. As you can see the German rounds are much shorter overall so had a much shorter effective range than their American counterpart.