re: Roller Locking Actions
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Cocked&Locked
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Ardent said:Still a locked bolt, roller locked, just a different system of accomplishing it.
the roller lock is really not a mechanical lock like the tilting breech block of say an fn or ak, its just a way of slowing down the opening slightly with mechanical dis-advantage, it's never really locked. If you shut of the gas with a locked action you have a single shot, with a G3 this can't be done.
Correct me if I'm wrong, it's not like I know everything, I just sometimes think I do
Ardent
CGN Ultra frequent flyer
Beater said:
You got it same principle
Rollers are forced outward holding the bolt in place while the pressure is peaking, as it comes down the rollers fall in and the bolt cycles. Cocked you raise good points, though I personally still see the roller locking as a lock, it just doesn't use gas piston operation. It is certainly locked against the peak pressure and holds back a good deal of force until the pressure decreases. I think this is a matter of interpreatation though, as this is just my take, your's is reasonable too.
Cocked&Locked
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Ardent said:You got it same principle
Cocked you raise good points, though I personally still see the roller locking as a lock, it just doesn't use gas piston operation. It is certainly locked against the peak pressure and holds back a good deal of force until the pressure decreases. I think this is a matter of interpretation though, as this is just my take, your's is reasonable too.
Holy cow!! someone who can agree to disagree with out a big slagging' match!This almost isn't like being on the INTERNET
. I went and checked out a few things to confirm before I shot my mouth off some more. The G3 really has no gas system. All the energy to operate the mechanism is coming from the recoil/back pressure of the round fired, ergo its a blow back. Since the pressure generated by high power cartridges is enough to separate the heads/split sides, you need to retard the opening somewhat. Hence your toggles and rollers. It really is an ingenious system!, but it's never locked up, just slowed down. It's never stationary, just moving slowly. Thats why they need the flutes, its pulling the case back wards as high pressure is trying to lock it to the chamber walls, and worse its doing it while accelerating fast. In a locked action, the pressure drops to a lower level before opening, and the extraction begins with a slower rate of movement as the action unlocks and then begins moving. My argument would be that if you put pressure to an FN, AK, SKS what have you, you'll have to do mechanical damage to open it without unlocking the action, where as with the G3 it will just be pushed open. What you do get is an action that works, with fewer moving machined parts that is cheap and easy to build on a low technology base (IE. third world countries, they want to build it there but don't have the tech base or economy to support aluminium forging etc. Other then the barrel and bolt, most of the unit is stampings and mouldings. A very good design, evolved from the production methods pioneered in the MP-40, MG-42 and Mp-44.
End of rant/lecture/venting of hot air, chose the appropriate description
Close, the German government paid for the CETME license after FN refused to license Germany to build the FAL.After the license was bought then HK was set up to build the rifles for the government. At first Rhienmettal also was set up but they moved their interest to other areas after their obligation was up. The part about the engineers is right but they went to work in France first, then Spain.CanAm said:
Actually, you are not correct.Cocked&Locked said:the roller lock is really not a mechanical lock like the tilting breech block of say an fn or ak, its just a way of slowing down the opening slightly with mechanical dis-advantage, it's never really locked. If you shut of the gas with a locked action you have a single shot, with a G3 this can't be done.
Correct me if I'm wrong, it's not like I know everything, I just sometimes think I do
When the bolt is in battery, the rollers are forced outward into their locking notches in the breech, by a spring loaded, solid, tapered "pin" that sits between the rollers inside the front 1/2 of the bolt. This is where the term "roller-locked" comes from.
The bolt is a 2-piece affair. The rear 1/2 of the bolt is anchored to the aforementioned "pin", and the 2 halves are held together with an internal spring.
Upon firing, the "blowback" force is conducted through the front 1/2 of the bolt (that is locked in place), to the rear bolt-half, exactly as energy is transfered when the first of 2 billiard balls, sitting in contact, is struck by the cue ball. This causes the rear 1/2 of the bolt to travel rearward, pulling the tapered "pin" backward, from between the rollers in the front bolt-half. This unlocks the rollers, and allows the rollers to move inward in the bolt, unlocking the bolt from the breech notches. The front bolt-half, being attached to the rear half is then pulled backward from the breech initiating ejection and the rest of the reloading cycle.
The time it takes for the force to be transmitted through the bolt and to move the rear bolt-half against the internal spring rearward enough to unlock the front bolt-half rollers is about the time it takes for the bullet to exit the barrel. Hence "delayed, r/l, blowback" This is why the system is so inherently accurate. This system fires from a breech that is every bit as locked as a bolt-action receiver, and essentially no mechanical activity begins before the bullet has left the barrel.
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Cocked&Locked
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nairbg said:
My argument exactly for NOT terming the action locked, only delayed. A locked action cannot be opened by force on the bolt, it is locked closed. A delayed action opens as force transmits through the bolt, CETME. The difference is academic, but important. It is a very accurate and robust action, I'll give that point to you and double it myself. All the rollers do is slow down the rearward movment enough not to allow the case to rupture. Part of the reliabiliy of the action is that fact that it opens NOW, due to the comparitivly high chamber pressure still present when cycling. Also why they can sure lob brass into the next area code.
I think most of our dissagreement here is semantic.locked or not
hey guys interesting thread perhaps i may chime in, here we go.
this is why i beleive its lock breach.
direct force applied to the bolt face will not unlock a g3, if you were to insert a wooden or steel rod (not advisable) down the bore from the muzzle and apply force the bolt would not unlock no matter how much force you applied, it would simply damage the bolt before it unlocked this is the same with ar or fn. so in saying this take the browning hi power pistol which is delayed blowback.i understand its a handgun but its delayed blowback as has been suggested about the g3 in this thread so bear with me.if you were to insert same said rod down the bore and apply pressure at some point it will unlock by direct pressure on the bolt face, hence delayed but not locked.
this is my argument for roller locked not delayed.thanks for listening
hey guys interesting thread perhaps i may chime in, here we go.
this is why i beleive its lock breach.
direct force applied to the bolt face will not unlock a g3, if you were to insert a wooden or steel rod (not advisable) down the bore from the muzzle and apply force the bolt would not unlock no matter how much force you applied, it would simply damage the bolt before it unlocked this is the same with ar or fn. so in saying this take the browning hi power pistol which is delayed blowback.i understand its a handgun but its delayed blowback as has been suggested about the g3 in this thread so bear with me.if you were to insert same said rod down the bore and apply pressure at some point it will unlock by direct pressure on the bolt face, hence delayed but not locked.
this is my argument for roller locked not delayed.thanks for listening
All this G3 talk has me sad. Wish I could legally buy one. From what I read a long time ago it was much more accurate then the FAL unlike what some people say. You just need the proper load, Anyhow isnt it also supposed to be more accurate because the action moves after the bullet has left the gun (hence delayed)?
Excellent comparison and explanation of the difference between the HK ROLLER-LOCKED delayed blow-back, and simple dlealyed blow-back. You are correct...... the rollers actually lock the breech as solid as any bolt -action rifle does. The blowback provides the energy to the 2-piece bolt to first unlock the bolt, and THEN to cycle it. A definite 2-step process, unlike straight "blow-back" or "delayed blow-back".bluestratus said:
bluestratus you actually have it backwards. The more presure you place against the boltface of an HK bolt head the more rigid it becomes. The locked systems use a mechanical system to push the rollers or tilt/ rotate a bolt. The MG42 has a cam system that pushes the rollers into and out of the locked position. The HK system uses math. I don't expect any more than a handful of people to understand this. As the force gets higher the more the rollers press against the barrel collar. If you look at the impulse from an HK action you can see that it fits the integral of the shape and force applied. As the pressure drops the force is not applied equally. At this piont the rollers slide past the collar.
MG42
surfaces I,D and the roller slots in the bolt head are the camming surfaces in this rifle.
HK
The red arrows are the force applied by the bullet being fired.
MG42
surfaces I,D and the roller slots in the bolt head are the camming surfaces in this rifle.
HK
The red arrows are the force applied by the bullet being fired.
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Cocked&Locked
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OK, but unlike a locked breach action, and unlike a browning HP (which is locked, not a blowback) at no point in the fireing cycle is the bolt of the G3 staionary. The ball/cam arangement slows the motion, but never stops it. The case is moving and extracting from the chamber, but only a small amount. As the pressure drops, the resistance from the camming action drops and it opens. With a HP, the action will not open untill it has moved far enough to the rear for the cams below the barrel to pull it down out of the locked position with the slide. The delayed blowback action is not a locked action, it is a blowback one, the fact that the blowback is retarded is incidental. The standard handgun action is a short recoil locked action with centerfire cartridges with very few exceptions for low powered rounds (.25, .32) The astra's where an anomoly that has not been repeated more than once (and you better be in shape to pull that slide back)
almost. If the presure gets high enough it will be stationary.Cocked&Locked said:
There is no camming action on the rollers. It is a resistance to motion. Camming has a different meaning than what the rollers are doing in this operation.Cocked&Locked said:
I would agree. except that the delay had to be built in for the HK mechanism and is not incidental.Cocked&Locked said:
