In a recoil system, inertia is used to cycle the action and load the next round. In a gas system, some of the combustion gas is bled-off to cycle the action.im not sure i understand. gas operated means that the gas produced by the burnt powder moves a mechanical piston that pulls back the slide (ejecting the spent cartridge) and then the slide by action.reaction moves back front (loading the new cartridge from the mag).
recoil operated means what exactly? recoil is produced by the same expanding gas. so what is the difference?
the inertia that moves the slide back is generated by the expanding gases, isnt it?
geni, welcome to the brawl but the truth of the matter I was the butthead and the Virginian was the calm head. The M14 you speak of I presume is essentially an M1 Garand with a box magazine in 7.62 NATO/308 Winchester. To answer your implied question where is recoil? Recoil started the very instant the bullet started to move and continued long after the bullet was gone. It is that recoil that continues to operate the action. You have to remember, if the rifle recoiled at the same rate of speed as the bullet, it would kill you to shoot it. However, as you know for every action there is an equal and opposite reaction. The mass of rifle absorbs this action/energy for a much longer period of time than the much lighter bullet. This can readily realized in the fact that the bolt does not travel back at the same speed of the bullet, meaning that a bullet could possibly depending on the range reach its target before the action completes its cycle. Your M16 comments I am not sure I understand so I won't comment. The FN-Fal has the feature of being able to shut the gas off to launch grenades and to work the action manually if need be. I think it has one more adjustment for blanks but I am not sure, I will look at one mine tomorrow and report back. The Styer Aug has this same feature as the FN but again I will have to check. I am fortunate enough to own these guns and while I don't have an M14 I do have a BM59 and I think one can adjust the gas on it because it has a grenade launcher. Again I will report back.Taking your brawl a bit further, with a few specific examples:
M-14 rifle gas piston "hits" the operating rod hard, but also pushes it a fair distance- 1/2 inch? That hammer-like hit imparts a high-force impact which both unlocks and drives the bolt back. Recoil effects may be present to some degree, but consider that the gas is bled to the piston just before the bullet leaves the barrel, so recoil by then is....??
M-16 impinges gas pressure on the bolt carrier "key" for a very short distance- maybe less than 1/8 inch? That "chuff" of gas-induced force is very short duration, before the gas bleeds away.
FN-FAL has an adjustable gas pressure regulator, a nice feature, if it works. I am not aware of any other common rifle having this.
Close, but not quite. Actions that work from the cartridge directly pushing against the bolt are known as direct blow-back actions. Most .22 LR semi autos and other rimfires fall into this category. Typically, this actions don't have locking lugs in their bolts because the bolt does not actually lock into anything. The mass of the bolt is enough to keep the breech closed temporarily until the pressure falls to safe levels. These actions work by taking advantage of mass to overcome momentum (the momentum imparted on the bolt). This is the simplest type of semi-auto action but it's not suited for high pressure cartridges.I know the post above went into great detail, but let me say the abridged version...
All ammunition releases a gas, but that's not what you should focus on. It matters where the gas goes to answer your question. In a recoil operated system, it's basically a force from the shell directly pushing on the bolt. The gas operated system takes gas from in front of the casing, diverts it from the barrel and into a piston. This piston is then pushed back by the gas. The piston is attached to an operating rod, which is attached to the bolt. You see where the difference is now?
H2o, the M-14 I speak of is as you mentioned, the successor to Garand. The distance of gas piston movement is limited to a fraction of the entire bolt travel, so analysis by "gut instinct" is pretty difficult, but suffice to say that I believe the piston imparts a very rapid impact hit to the operating rod, which develops sufficient peak force during that instant of contact, that inertial forces then keep the rod (and bolt) moving rearward to complete the cycle. Whether any recoil force is involved is rather doubtful, since the bolt is essentially a mechanical part of the chamber until the gas piston moves the op rod, which in turn moves the bolt rearward as the locking roller "cams" upward, relieving the mechanical lock-up to the chamber. That event is happening MUCH later than when the bullet passes over the gas orifice (allowing gas flow to the piston). So, the bolt is locked until the bullet leaves the barrel, with the net result that there are then no longer any gas forces acting on the cartridge (or the bolt, therefore), to provide "equal & opposite reaction".genie:Well here I go again looking for another crow to eat and I haven't fully recovered from the last one. The only good thing is don't let it be said that I cannot admit when I am wrong. The M14/ BM59 has a gas piston that runs the full length of and operates the action entirely by gas. Recoil does NOT come in to play as I suggested.