This new thread would have value if it's title was "Autoloading action primer". As a physics thread it is so-so.
[U]I think 1911Tuner’s title if not precise is sufficient for all to understand what the thread is about from the context of the text. You suggestion in not precise either as it could be a title for a thread about a new time of primer specifically created for guns having autoloading actions. There is enough text in your posts to wade through so this kind of stuff just obfuscates.[/U]
In the other thread I responded to every major point with solid counter examples, all of which 1911Tuner ignored, presumably so he wouldn't have to deal with them.
So, here we go again:
All locked breech actions remain locked for some period of time. All unlocked actions are never locked.
What kind of action is unlocked? Even the simplest blowback action is locked by the inertia of the slide until gas pressures become strong enough to over come that inertia. Just because a mechanical lock is not present it does not mean the action is without a lock.
All autoloading actions use energy derived from the firing of a cartridge. That isn't a physics problem, just an observation that none of them have motors. How that force is harnessed to open move the action and what sort of pros and cons come with each is why we bother to have terms like "blowback".
Here are all the different major action types for breech-loading autoloaders:
Locked breech recoil. Long recoil ejects the casing when the barrel is moving forward and the breech is locked back, short recoil ejects the casing when the barrel locks in position and the breech continues back. Secondary extraction - the extractor has to pull the casing out of the chamber.
Locked breech inertial unlocking. Used in some Benelli shotguns. Uses a locked breech with extraction provided by residual chamber pressure. Primary extraction.
Locked breech gas unlocking. Gas from the bore is tapped off to move a bolt carrier that angles the breech bolt so that it unlocks from the barrel, then pulls the bolt back to secondarily extract the casing.
Unlocked blowback. Gas pressure formed between breech sealing cartridge casing and bullet provide pneumatic force on breech face that drives it open. Self extracting (primary extraction).
Unlocked blowforward. Gas pressure formed between breech sealing cartridge casing and bullet provide pneumatic force on breech face that drives it open. Self extracting (primary extraction).
This is incorrect. “Pneumatic force” (propellant gas pressure) and friction of the bullet in the barrel (essentially the bullet and barrel are locked together) along with the movement of the gun rearward is what operates the action.
Unlocked delayed blowback. Gas pressure formed between breech sealing cartidge casing and bullet provide pneumatic force on breech face that drives it open. Self extracting (primary extraction). Uses a secondary device to decrease the speed of the breech opening without resorting purely to breechface mass or spring pressure. Gas, leverage, rifling leverage and friction delays are most common. The "delay" is not a pause, just a decreased rate of acceleration.
We have these terms so they tell us what to expect out of the firearm. Locked breech actions provide protection against over pressure rounds. The extraction is usually secondary, and the extractor works hard to tug the casing out of the chamber. No matter how much pressure the chamber has or does not have, they generally won't cycle without the bullet moving out of the barrel.
Unlocked "blowback" (or forward) actions require the gas seal of the casing because they use chamber pressure to force the unlocked action open. In the event of an overpressure, they open that much faster. They cycle whether the bullet goes anywhere or not - all they need is chamber pressure.
Let's address this Barrel Friction nonsense. The only gun where barrel friction is actually a factor in the cycle is the FN FiveSeven. The high speed bullet's friction is enough to prevent the light slide/barrel from recoiling. Otherwise, the Browning Auto 5 short recoil shotgun demonstrates that barrel friction in recoil actions doesn't matter - high friction slugs cycle just like low friction buck shot. It doesn't matter what the friction is at 1 inch a minute - that isn't how fast the bullet moves and it isn't the same. Blowforward works because the barrel is a gas tube and bullet and casing are forcing themselves out of either end. If the breech won't go back, the barrel will go forward as the casing shoves its way out.
Here's some more previously ignored examples from the other thread:
If you replaced a Glock's barrel with a magnetic tube that hurled a loose fitting 150 grain slug at 1000fps, the barrel and slide would recoil opposite of this acceleration. The barrel would cam down and stop while the slide's momentum would cause it to continue, extracting anything that happened to be under the extractor hook. In this example, recoil alone caused the gun to function normally. The same barrel installed on a blowback or blowforward gun would cause nothing to happen, despite the slug also heading out the barrel at 1000fps. Recoil did it all.
I don’t believe in your scenario that enough recoil will be generated to operate the action. You are implying making the Glock an electrically powered magnetic driver. The moment the “150 grain slug” leaves the barrel there is no remaining pressure. When a real Glock unlocks there is still remaining gas pressure on the face of the slide. I think you would have to greatly exceed 1000fps before this could be possible.
If you squibbed the barrel of a Glock, blowback and blowforward guns, then fired a high pressure blank in all three, you'd find the Glock wouldn't move at all, and both blow guns would eject their casing. Recoil, known in physics as the equal and opposite reaction to acceleration, didn't power the Glock. Gas pressure acting on the breech didn't power the Glock, either. It only powers a breech that is open to gas pressure action - unlocked breech guns.
Can a blank cycle a recoil operated gun? Sure, as long as the sum total of the mass times velocity of the gas and packing is equal to the minimum bullet momentum that will cycle the gun. Chamber gases have mass, and if they are moving a cotton wad fast enough, they can have significant enough momentum. But most recoil guns won't work this way.
Agreed this is theoretically possible with enough propellant mass.
Can a blank cycle a blowback? Similar problem, but now it is a question of chamber pressure being high enough with no bullet sealing the other end of the bore. Make the slide or spring lighter, and it becomes possible to get enough chamber pressure.
Can a blank cycle a gas operated rifle? Like a blowback, the problem is again creating enough pressure in the barrel and gas system despite not having a bullet to seal the other end. Devices are made for this.
What happens if you don't use a casing? Say you loaded a recoil and blowback gun like a blackpowder gun with a loose bullet and no brass. When fired, the gas would leak at the breech of the Glock, but the gun would still cycle. The blowback gun would blow open it's breech immediately, lose all chamber pressure and the bullet would just sit there and the slide would close after only moving a tiny distance. Another fine example of the difference between the pneumatic forces driving a blowback and the recoil forces working in a recoil operated Glock.
What happens if you double load round with too much gunpowder? If it doesn't blow up the barrel, the Glock is going to fire the bullet downrange, cycle the action and eject a spent case. The blowback or delayed blowback gun is going to have the action open faster than normal (more pneumatic pressure) and the casing is going to rupture, blowing brass and hot gas everywhere. That's the primary functional difference between locked actions and unlocked - gas pressure doesn't matter to the locked actions, but it is a major safety problem for unlocked blowback actions.
This is just wrong. Double charges have the potential for “blowing up” a barrel if that means cracking it. It depends on how fast peak pressures are reached and the quality and design of the barrel.
Summary: You can drive a recoil action with pure recoil, no gunpowder needed. But you do need something accelerating enough to cause an equal and opposite reaction.
You can cycle a blowback gun without any recoil. All you need is enough gas pressure and casing that will seal it. The amount of gas pressure will dictate the speed the action opens, not the momentum of the bullet. Different powders could make the bullet have the same muzzle velocity with completely different slide speeds. This is not possible with a recoil gun - slide velocity is only dictated by muzzle velocity, not bore gas pressure.
It drives me absolutely crazy that a cult of personality can overcome the real definitions of well understood terms and allow someone to argue his own new definitions. These terms all have real world applications. This is not the first time 1911Tuner has substituted his baloney for the facts and gotten away with it for awhile.
I think most people will think your “cult of personality” comment raises more suspicion about your credibility than 1911Tuner’s.
