i'm a new user in this forum
i have problems with my tesis
i need helps
i would like to know bout:
1) advantages/disadvantages of
a) gas system
The gas system of operation is the most popular system found in rifles, and has seem limited use in pistols, such as in the Desert Eagle. In this method of operation, gas is diverted through a hole in the barrel, usually around the front sight block, into a gas tube. There are three main variations of this system; the long piston, short piston, and direct gas impengement. In the long piston, such as that of the Kalashnikov family, the gas is directed into a rather large gas tube, hits a large piston, which is connected directly to the bolt carrier. This sends the entire piston and bolt carrier backwards with force and has the advantage of being very simple, and very reliable. The disadvantage would be that the large amount of mass moving increases felt recoil. In short piston operation, the gas hits a gas piston which is blown back to either impact the bolt carrier assembly (FN FAL) or hit an operating rod, which hits the bolt carrier (SKS). This is more complicated but minimizes mass movement, and thus recoil. Both of these systems are more maintence free than other operating systems because the pistons tend to keep hot gases and carbon fouling restricted to the gas tube and out of the weapon's receiver. The direct gas impengment system is basically seen only in the AR-15 series. It gets rid of the gas piston all-together and simply directs gas through a narrow gas tube into a gas key, a tiny port directly in the bolt carrier, to blow it back. This makes the system very simple and very accurate, but tends to allow a lot of heat and fouling into the receiver.
b) recoil system
c) blowback system
As far as I am aware, recoil operation is basically the same as blowback. There is blowback operation and delayed recoil operation, but both operate off of recoil, or more precisely, the physic's concept of equal and opposite. Blowback operation is basically restricted to rimfires and low-powered pistols. The Ruger 10/22, Ruger Mk II, and the James Bond's .380 ACP Walter are all blowback operated. The same forces that push the bullet down the bore push backwards towards the shooter as well. This is known as recoil to us. The only reason it doesn't hit us as hard as it hits the target is the mass of the handgun or rifle is much more than that of the bullet. But this only works with relatively low powered cartridges because at peak pressure, the forces generated by the more powerful cartridges would be too violent to control. In order to control anything larger, you need to either dramatically increase the mass of slide, such as the HiPoint pistols, or create a mechanism to delay operation of the bolt or slide until pressures have dropped to a safe level. In pistols this is most often accomplished with a series of lugs and a link that holds the barrel in place until pressures are safe, then allows the barrel to tilt downwards, unlocking the lugs, and allowing the slide to travel rearward. This is seen in the 1911 Gov Model as well as the vast, vast majority of all automatic handguns you see from the Glock to the SIG, ect. The only popular recoil operated rifles that I am aware of is the HK roller locks like the G3. They control recoil with a two-peice bolt which delays through inertia the transfer of recoil forces to a series of locking ball bearings until pressures are safe. The HK series roller locks are usually very reliable and very accurate, but can have the fouling issues of the AR series. Also, even with the locking system, the action of the HK roller locks is still very violent which asside from increasing felt recoil can lead to torn case heads. HK designed a fluted chamber to remedy this, though.
As for the best system, I don't really know if there is a singular "best" system. Any of them should be evolved enough now that there are very good representatives for all of them.
