Field Artillery
Both are tracked vehicles. An assault gun is usually a turret less vehicle, mounting a (usually) high velocity gun used in a direct fire mode, used for attacking an enemy position. A self propelled gun is usually an artillery piece (indirect fire), and is tracked to allow self propulsion.
Artillerymen fired: 105mm and 155mm field guns; 155mm and 175mm SPGs (Self Propelled Guns). US Tankers fired: 90mm cannons (M48 Patton tank main gun) and 152mm cannons (M551 Sheridan tank main gun). Australian tankers used Centurian tanks which fired 84mm main guns (20 pounders). South Vietnamese tankers used the M41 Walker Bulldog light tank, which fired a 76mm main gun. North Vietnamese Army (NVA) tankers used the PT76 light tank which fired a 76mm main gun and the T54 medium tank which fired a 100mm cannon.
By far the most common US howitzer was the 105mm split trail (towed piece). The most common SP (Self Propelled gun) was the 155mm SP. There were some SP 175mm, 8 inch SP, and 155mm split trails in use. Unless their tubes were wore out, they were all accurate.
US Army artillery used in Vietnam primarily consisted of : 1. 175MM Self propelled guns 2. 155MM Self propelled guns 3. 8 inch Self propelled guns 4. 40MM M-42 Dusters (twin barrels), built on an M-41 Walker Bulldog light tank hull 5. 155MM Field gun, split trails 6. 105MM Howitzer, split trails 7. 4.2 inch Mortar 8. 81MM Mortar 9. 106MM Recoilless Rifle 10. 90MM Recoilless Rifle With the exceptions of COMPUTERS and SMART WEAPONS (Smart Shells), and new light weight cannon for transport purposes, there is probably little physical difference between the artillery of Vietnam and today. The recoilless rifles have been replaced by medium & heavy anti-tank missile systems, the 175MM and 8 inch Self Propelled Guns have probably been retired, and the M-42 Duster is now a museum piece.
To deflect projectiles, thus allowing it to advance forward. This is the definition of a tank: Gun & Armor. Remove the gun; it becomes an armored personnel carrier. Remove the armor; it becomes a self propelled gun (artillery). Retain the gun & armor; it is a tank.
The rocket powered projectile does not have to be in a gun.
the bullet case
1. Battleship USS New Jersey, 16" guns 2. US Navy heavy cruisers armed with 8" guns 3. US Navy light cruisers armed with 6" guns 4. US Navy destroyers armed with 5" guns 5. US Artillery: 175mm self propelled guns 6. US Artillery: 155mm self propelled guns 7. US Artillery: M56 SPAT 90mm self propelled anti-tank gun 8. US Artillery: M42 Duster; twin 40mm pom-pom guns 9. US Artillery: 8" inch guns 10. US Artillery: split trail 105mm and 155mm field guns (towed pieces) 11. USMC: M50 Ontos (six 106mm recoilless rifles)
The Russian 2S7 "Peony" self-propelled gun is the biggest tube artillery system in use anywhere in the world. It can drop a 203mm shell 37,500 meters from the muzzle.
well... yes but try a gas propelled one
Same as a battleship (battle tank)=Armor & Gun. Examples: Remove the gun, you'll have an armored personnel carrier. Leave the gun but remove the armor and you'll have a SPG (Self Propelled Gun=Artillery piece). Retain them both=Main Battle Tank. Same with the battleship; remove the guns you have an armored vessel. Leave the guns but remove the armor and you've got a heavily armed cruiser.
All tanks are armored; if they weren't armored they would be called self propelled guns (because they have a cannon mounted on them). It they were armored, but didn't have a gun (cannon) it would be called an armored personnel carrier. Therefore, since it's got armor & a gun, it's called a tank.