CGRifleman
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If recoil-operated systems are, in theory, more reliable than gas-operated, why are there so few (if any) recoil operated semiautomatic rifles on the market today?
Recoil Operated Rifle... why not?
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briansmithwins
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Because every one I can think of requires a recoiling barrel.
Moving barrels and rifles don't actually work all that great in the real world.
Crew served weapons get away with it by usually encasing the barrel with a shroud. Which is a big weight penalty for a individual rifle.
BSW
Moving barrels and rifles don't actually work all that great in the real world.
Crew served weapons get away with it by usually encasing the barrel with a shroud. Which is a big weight penalty for a individual rifle.
BSW
ColeK
Member
And recoil would bad.
jogar80
Member
Hmm... I'm guessing you mean something like the benelli shotguns where the bolt is recoil operated.
I don't know why there aren't any, lol.
...................I'm so useful.......
I don't know why there aren't any, lol.
...................I'm so useful.......
mortablunt
Member
As has been said, there is the issue of the recoiling barrel. The Johnson M1941 would have been a recoil rifle issued to a military force, but then the Japanese spoiled it. The Marines used a few.
http://en.wikipedia.org/wiki/M1941_Johnson_rifle
The bayonet didn't work because stabbing someone would have operated the action. And imagine using optics on a moving barrel
http://en.wikipedia.org/wiki/M1941_Johnson_rifle
The bayonet didn't work because stabbing someone would have operated the action. And imagine using optics on a moving barrel
rcmodel
Member in memoriam
But, you can top off an M1 Garand clip.
There are two ways to accomplish "topping-off".
The obvious & best way is to eject a partially-empty clip and reload with a full one.
Then save the loose rounds until you have 8 to load another clip with.
The other way is to lock the bolt back by pressing down on the bolt lock stud and insert loose rounds into the clip in the weapon.
rc
There are two ways to accomplish "topping-off".
The obvious & best way is to eject a partially-empty clip and reload with a full one.
Then save the loose rounds until you have 8 to load another clip with.
The other way is to lock the bolt back by pressing down on the bolt lock stud and insert loose rounds into the clip in the weapon.
rc
henschman
Member
If you mean a blowback operated rifle, they aren't a popular design because rifle rounds generally produce too much pressure to work that way... some sort of mechanism is needed to allow the pressure in the chamber to drop to a safe level before the case is extracted. HK uses a "delayed blowback" design with a fluted chamber and locking rollers on the bolt. For all its faults that system is definitely very reliable. And as others have mentioned some designers have toyed with the idea of a reciprocating barrel. This isn't usually very conducive to accuracy though.
mortablunt
Member
Yeah, but the army didn't recommend that. If I remember from something on History Channel (before it became reality show channel), it said that soldiers were advised to empty out the clip and then insert a fresh one.
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average_shooter
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In my experience with a recoil operated shotgun, there's a little more felt recoil since there is not a gas system to soak up some of the energy. So making a recoil driven semiauto rifle in anything more than .22LR might get pretty punishing. Just think about how little recoil there is with a standard AR-15, how long would you want to shoot one if you were getting the whole blowback force / recoil of the round driving into your shoulder on every shot?
As far as recoiling barrels causing problems in the field, the M82-A1 / M-107 has been pretty popular from what I can tell.
As far as recoiling barrels causing problems in the field, the M82-A1 / M-107 has been pretty popular from what I can tell.
airedaleman
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You young guys probably don't remember the Model 8 and 81 ( a 'modernized" Model 8) Remingtons, a long-recoil design by John M himself. The barrel and recoil spring were housed in a tubular shroud that carried the sights. Chambered for Remington proprietary cartridges (.25, .30, .32, and .35 Remington and - in the Model 81 - .300 Savage), these were heavy, finely machined firearms that enjoyed a fair amount of popularity from their introduction in 1905 to the middle of the last century. I had a Model 8 in .25 Remington. There was virtually no recoil but you could feel and hear all that wonderful machinery working as the action cycled. It was a hoot.
Texas Ranger legend Frank Hamer favored the Model 8 and used one to perforate Bonnie Parker and Clyde Barrow quite a few times.
Texas Ranger legend Frank Hamer favored the Model 8 and used one to perforate Bonnie Parker and Clyde Barrow quite a few times.
armoredman
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The Russians fielded a recoil operated rifle recently, "A" something, complex machine from what little I remember.
MachIVshooter
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They did 100 years ago:
The first thing that comes to mind is that recoil operated guns are not generally as accurate as designs with fixed barrels. Once you have the barrel and sights moving independently, there's a lot more room for error between the two. Recoil operated guns are also not as reliable in unorthodox firing positions, which is a concern for military forces. Also, you can't hang stuff on the barrel (laser, front grip, bipod, etc) without affecting the function of the gun (hence the little spike bayonet on the Johnson).
1911Tuner
Moderator Emeritus
That's what happens with a .223 bolt-action rifle...and the recoil is nothing more than a gentle nudge.
krinko
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From "Hatcher's Notebook" page 259:
"The lighter the parts that oppose the thrust of the explosion, the greater the energy they acquire. Thus in the gun mentioned, the light recoiling parts, driven backwards at high speed inside the barrel casing take up a heavy load of energy, then come to a stop against the inside of the receiver and transmit a large part of that energy to the shoulder of the shooter. The result is that the gun has a particularly viscious kick. Shooting this rifle was what first called our attention to the fact that in a self loading gun of the recoiling barrel type the whole weight of the gun was not utilized against the recoil."
This is from Chapter 11 "Block That Kick--Some Observations On Recoil" and the whole text, which I am not prepared to transcribe, goes into much greater detail.
"Hatcher's Notebook" ought to be in every bullethead's library.
-----krinko
"The lighter the parts that oppose the thrust of the explosion, the greater the energy they acquire. Thus in the gun mentioned, the light recoiling parts, driven backwards at high speed inside the barrel casing take up a heavy load of energy, then come to a stop against the inside of the receiver and transmit a large part of that energy to the shoulder of the shooter. The result is that the gun has a particularly viscious kick. Shooting this rifle was what first called our attention to the fact that in a self loading gun of the recoiling barrel type the whole weight of the gun was not utilized against the recoil."
This is from Chapter 11 "Block That Kick--Some Observations On Recoil" and the whole text, which I am not prepared to transcribe, goes into much greater detail.
"Hatcher's Notebook" ought to be in every bullethead's library.
-----krinko
1911Tuner
Moderator Emeritus
While I don't mean to beat on Hatcher unnecessarily...that statement focuses on velocity and energy and ignores the bigger picture. The less massive the reciprocating part, the faster it's accelerated and the higher its terminal velocity...but that's only a small part of it.
Since the actual recoil is acceleration, and the result of that acceleration is momentum...and it's momentum that we recognize as felt recoil...not energy. While the bolt does impact the receiver...when it does, the whole mass of the rifle is absorbing that impact. Back to square one.
Mass and momentum are the factors that determine how hard the rifle "kicks" us.
Think of it this way.
If you have to knock a brick wall down, are you going to pick up a carpenter's hammer that you can swing at high velocity...or a 10-pound sledge? Speed/energy vs mass/momentum. Speed and energy will sting. Mass and momentum will belt you around.
@ armoredman - I think you are talking about the AN94 and it is a unique operating system that (as I understand it because I have never handled one) uses a combination recoil and gas system.
For further clarification on some of the responses, one must remember that recoil operation is not the same as blowback.
In a blowback firearm, the breach is not locked and sealed by the action spring and mass of the bolt. The weight of the bolt must be tuned to resist movement long enough (inertia) to keep the breach sealed until pressure drops to a save level (see most semi .22s, Thompson, and the Mk19 grenade launcher).
In a recoil operated firearm, the breach is locked and the "recoil" of the firearm is the force that unlocks the bolt and cycles the action. This is usually accomplished by the barrel and bolt moving together for a period of time and then being forced apart (see most semi centerfire handguns and the Browning M2 and Auto 5).
Benelli did something a little different with their recoil system and doesn't require the barrel to move by incorporating an inertia mechanism inside the bolt to allow the bolt to unlock (anyone more familiar with this system, please correct me if I am wrong). This system is dependent the rearward movement of the whole firearm when fired. It normally works well, but as Benelli found out when developing the new shotgun for the military, adding lights, sights, sidesaddle ammo holders, etc. can alter the recoil characteristics of the firearm and cause malfunctions in cycling. That is why Benelli abandoned their recoil system for a gas system in that gun.
Also, this thread is based on the premise that a recoil operated firearm is more reliable. I have to ask, how so?
For further clarification on some of the responses, one must remember that recoil operation is not the same as blowback.
In a blowback firearm, the breach is not locked and sealed by the action spring and mass of the bolt. The weight of the bolt must be tuned to resist movement long enough (inertia) to keep the breach sealed until pressure drops to a save level (see most semi .22s, Thompson, and the Mk19 grenade launcher).
In a recoil operated firearm, the breach is locked and the "recoil" of the firearm is the force that unlocks the bolt and cycles the action. This is usually accomplished by the barrel and bolt moving together for a period of time and then being forced apart (see most semi centerfire handguns and the Browning M2 and Auto 5).
Benelli did something a little different with their recoil system and doesn't require the barrel to move by incorporating an inertia mechanism inside the bolt to allow the bolt to unlock (anyone more familiar with this system, please correct me if I am wrong). This system is dependent the rearward movement of the whole firearm when fired. It normally works well, but as Benelli found out when developing the new shotgun for the military, adding lights, sights, sidesaddle ammo holders, etc. can alter the recoil characteristics of the firearm and cause malfunctions in cycling. That is why Benelli abandoned their recoil system for a gas system in that gun.
Also, this thread is based on the premise that a recoil operated firearm is more reliable. I have to ask, how so?
It's basically an heavy, inefficient design with a high probability of reduced accuracy. In a crew served MG, the rails can be sufficiently heavy to control the repeatabiilty of hitting the POA in a consistent manner, but scaling that down to a infantryman's rifle under 7 pounds bare isn't likely. Other methods like DI or manual actions do more, with less, more accurately.
No matter what the actual method, a barrel recoiling in ways must have clearances, and that means locked or not, the POI will never return to the exact same position every time. Prove it to yourself, take your favorite bolt gun and loosen the action screw enough to get +.0075" between the action and bedding.
To keep most of the slop locked up, it's going to take some metal, as it's the most cost efficient material, and that means it's going to be heavier, with more machining. All contrary to the trend over the last 100 years to remove excess steel and eliminate machining wherever possible. Hence, the creation of the polymer firearm. Even the forged aluminum AR15 is under revision - most of the new battle rifles are polymer lower, extruded upper. Forging is no longer the most cost effective in mass production terms.
There's another mechanical trend, too. The elimination of parts that reciprocate. In self loading actions, we've gone from gas trap, and piston, or blowback in various delayed forms, to DI. All necessary to eject a case. If there is no case, then that cyclic action is no longer necessary, and you get the shuttle bolt of the LSAT moving sideways. Recoil isn't a major problem in intermediate cartridges anyway, precisely their nature and exactly why they were invented. A recoil operated weapon would be attempting to use a characteristic that modern trends have significantly diminished, making it harder to operate in an optimum window.
The concept is similar to a diesel powered moped. Haven't seen many of those.
No matter what the actual method, a barrel recoiling in ways must have clearances, and that means locked or not, the POI will never return to the exact same position every time. Prove it to yourself, take your favorite bolt gun and loosen the action screw enough to get +.0075" between the action and bedding.
To keep most of the slop locked up, it's going to take some metal, as it's the most cost efficient material, and that means it's going to be heavier, with more machining. All contrary to the trend over the last 100 years to remove excess steel and eliminate machining wherever possible. Hence, the creation of the polymer firearm. Even the forged aluminum AR15 is under revision - most of the new battle rifles are polymer lower, extruded upper. Forging is no longer the most cost effective in mass production terms.
There's another mechanical trend, too. The elimination of parts that reciprocate. In self loading actions, we've gone from gas trap, and piston, or blowback in various delayed forms, to DI. All necessary to eject a case. If there is no case, then that cyclic action is no longer necessary, and you get the shuttle bolt of the LSAT moving sideways. Recoil isn't a major problem in intermediate cartridges anyway, precisely their nature and exactly why they were invented. A recoil operated weapon would be attempting to use a characteristic that modern trends have significantly diminished, making it harder to operate in an optimum window.
The concept is similar to a diesel powered moped. Haven't seen many of those.
With recoil operated guns you have such a large, and long, reciprocating mass . You can just imagine the weird harmonics you can get.
Brassey’s says this about long recoil:
1) Reduced stress as the recoil energy can be dissipated over a long movement.
2) A very low rate of fire
3) Complex , expensive mechanism requiring heavy, expensive barrel bearings.
4) A large change in center of gravity as the mechanism cycles.
Long recoil has been used, Brassey’s small arms mentions the Rarden 30mm Cannon. The Brits wanted a low rate of fire as the Rarden was attached to an APC.
The books I own call the HK roller bolt delayed blowbacks.
The innovation that makes roller bolts work is the fluted chamber. Roller bolts open so early in the pressure curve, and they open so fast, that the frictional forces between case and chamber are extremely high. Without flutes to float the upper 2/3 rds of the case off the walls, the rim would be pulled off during extraction or the head head would be pulled off.
The lower third of the case is your gas seal. The cartridge case is a gas seal, not a structural element, it does not carry load. It must be supported or it will rupture, and that is true in all mechanisms, long recoil, short recoil, gas, manual, single shot.
The quickest way to jam a HK91 type mechanism is to gum up the flutes. The flutes must be kept clean in these things.
Brassey’s says this about long recoil:
1) Reduced stress as the recoil energy can be dissipated over a long movement.
2) A very low rate of fire
3) Complex , expensive mechanism requiring heavy, expensive barrel bearings.
4) A large change in center of gravity as the mechanism cycles.
Long recoil has been used, Brassey’s small arms mentions the Rarden 30mm Cannon. The Brits wanted a low rate of fire as the Rarden was attached to an APC.
The books I own call the HK roller bolt delayed blowbacks.
The innovation that makes roller bolts work is the fluted chamber. Roller bolts open so early in the pressure curve, and they open so fast, that the frictional forces between case and chamber are extremely high. Without flutes to float the upper 2/3 rds of the case off the walls, the rim would be pulled off during extraction or the head head would be pulled off.
The lower third of the case is your gas seal. The cartridge case is a gas seal, not a structural element, it does not carry load. It must be supported or it will rupture, and that is true in all mechanisms, long recoil, short recoil, gas, manual, single shot.
The quickest way to jam a HK91 type mechanism is to gum up the flutes. The flutes must be kept clean in these things.
The Remington Model 8, 81, and Fabrique Nationale Modele 1900 were all long-recoil operated centerfire rifles. The Remington's were well known in their day and used by many law enforcement agencies, from Oneida, Co New York to L.A. County Sheriff's Dept.
Other long recoil firearms include the Frommer Stop pistols, the French Chauchat, and of course the Browning A5 (and variants). There is still one long-recoil produced civilian firearm, to my knowledge, and that's the Franchi 48AL (modern A5 type action).
All the recoil operated rifle info you could ever want here...
www.thegreatmodel8.net
Other long recoil firearms include the Frommer Stop pistols, the French Chauchat, and of course the Browning A5 (and variants). There is still one long-recoil produced civilian firearm, to my knowledge, and that's the Franchi 48AL (modern A5 type action).
All the recoil operated rifle info you could ever want here...
www.thegreatmodel8.net
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