Are guns ever rated for the amount of energy consumed by the action? For example, I did a bit of experimenting. I used the same cartridge in a bolt action rifle verses a semi-auto. The penetration in wood was significantly more with the bolt action. Also tested a Luger verses Glock, again same cartridge. The Luger requires more power to work the action and has less penetrating power. My issues that people talk about bullet weight, muzzle velocity, etc., but I haven't much about 'wasted' power.
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How much power does the action consume
- Thread starter Mallard
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Agree, but if you use the same cartridge (brand, weight, etc.) and fire it from two different guns, the muzzle velocity will be different due to more or less energy being consumed by the action. Ammo is sold by and advertised in fps. How can this be accurate if it varies depending on action.
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It also varies based on barrel length. They don't sell with a range on the side of the box saying "860fps in a 4" barrel!" They say 860fps. Ammo manufacturers tend to test in what they believe will be the most common firearm that round will be chambered in. Hunting bullets? I'm gonna say bolt action rifle. .38spl? Probably a revolver, 4" (because the stuff they test in a 2" says 2" on the box)
The best way to ensure the performance of any ammo is to chrono it yourself, from your gun.
The best way to ensure the performance of any ammo is to chrono it yourself, from your gun.
I'm sure it's FPS out of a some standard length/action they use for testing. Barrel length would make a much more significant difference. IE snub nose vs standard. Same with sub compacts vs full size handguns. I would be interested in seeing the results through a chronograph to demonstrate how much the action actually eats.
Mike
Mike
Thanks to John Browning the barrel remains locked to the slide on a semi auto pistol until the bullet has left the muzzle. So no energy is wasted before the bullet leaves. There are various ways to accomplish this but they all have roots in Browning's design.
radioman
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I think they test ammo in a universal receiver. It's just like a bolt action rifle but it's made out of a chunk of steel and mounted to a bench. They use it to test accuracy and velocity.
Wow, clean the sand out of your mangina. I wasn't crapping on you, just pointing out to the thread he was asking about rifles and hoping someone with more knowledge on the subject than I - as mine is casual at best - would chime in on that aspect of it.
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For every action there is an equal and opposite reaction. ie; conservation of mass/energy. You can't have the slide sent back and have that not rob energy from something else. The key is, to have that energy come from something not being used to propel the bullet. In 1911s, this is well done, but not 100%. In ARs, the gas system is definitely robbing the bullet of velocity. Hence why they sell extended length gas systems for match barrels (that has two benefits, velocity and delaying the blowback), etc. Is the system robbing a lot of power, no. But it is robbing something. The OP really is asking, is there a efficiency metric for semi auto actions and the answer is no. But it is not there isn't one because of no effect, it is no because it really isn't a huge deal until you start talking about competitive shooting and then you really care about barrel length.
+1 to that. From the limited info provided from the OP, I am betting that he is seeing different energies based on barrel length.
HooVooLoo
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With all of the variables involved in doing a true scientific test to answer your query, the only option in my mind would be to take a SA and bury it half-way into in a ton of concrete.
Put the round in, pull the trigger, and measure all the performance data.
Then, using the EXACT same round, assuring it has the EXACT same type/amount of powder, primer, case length and thinkness, bullet diameter and weight, crimp strength...
Drill a hole through the back of the slide and stick a nice sturdy bolt through it so the slide cannot move, and then fire the next round. Take measurements. That will show you the difference.
Between burying your piece in a hunk of concrete and destroying it by drilling through the slide/frame, I'd say it's not worth it to know the delta. Unless you have some SAs to burn, heh.
Put the round in, pull the trigger, and measure all the performance data.
Then, using the EXACT same round, assuring it has the EXACT same type/amount of powder, primer, case length and thinkness, bullet diameter and weight, crimp strength...
Drill a hole through the back of the slide and stick a nice sturdy bolt through it so the slide cannot move, and then fire the next round. Take measurements. That will show you the difference.
Between burying your piece in a hunk of concrete and destroying it by drilling through the slide/frame, I'd say it's not worth it to know the delta. Unless you have some SAs to burn, heh.
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See here: http://www.northeastshooters.com/vb...tion-consume?p=1518225&viewfull=1#post1518225
It's HooVooLoo's response above. This is what you would need to do to figure out the actual impact. I would add you would really need to take an AR barrel and plug the hole in half the tests to figure it out. But you need to isolate the variables. Anything else is pure speculation.
HooVooLoo
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Mallard, it isn't that simple if you are looking for exact comparisons. Every single factor must be taken into consideration in order to determine the true cause of muzzle-energy degradation.
For example, the slide in a SA will not start to move backwards until the bullet has separated from the case head and the gas starts to escape. As the slide moves backwards while the bullet moves forward, there will be, at any given moment, less gas pressure behind the bullet as oppossed to being fired from a bolt-action.
The more lands/grooves a barrel has, the more energy will be consumed as the bullet begins to spin. Some energy that would propel the bullet through a smoothbore cleanly must be imparted to overcome the friction of the bullet as it must spin through the rifling, all other factors being equal.
But with so many other factors involved, we cannot know exactly how much of a perfomance difference you are seeing between your test models, and what those causes may truly be. I suspect there is more involved than simply the fact that one is a SA and the other a bolt-action.
You can also calculate this roughly via slide or bolt weight, recoil spring strength, and velocity. The answer, however, is going to be "not that much". If you're seeing a difference in penetration, it's because of other factors.
MisterHappy
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The energy to operate the action has to come from somewhere.
That being said: just as there is no "perfect" round for all purposes, there is no "perfect" action.
Unless you have a very specific need ( as in the AR example with the delayed gas bleed mentioned above ) since there are so many other variables, it's likely not significant or even calcuable. Unless you have micro-managed match-grade ammo, the variation in performance round-to-round would likely be greater than any energy loss in the action's operation.
And, if the discussion is about the efficiency of different actions, let's toss revolvers in, where there is a loss of gas, and therefore energy at the front of the cylinder.![[pot]](/xen/styles/default/xenforo/smilies.vb/037.gif "Stir the pot [pot]")
![[laugh]](/xen/styles/default/xenforo/smilies.vb/012.gif "Laugh [laugh]")
That being said: just as there is no "perfect" round for all purposes, there is no "perfect" action.
Unless you have a very specific need ( as in the AR example with the delayed gas bleed mentioned above ) since there are so many other variables, it's likely not significant or even calcuable. Unless you have micro-managed match-grade ammo, the variation in performance round-to-round would likely be greater than any energy loss in the action's operation.
And, if the discussion is about the efficiency of different actions, let's toss revolvers in, where there is a loss of gas, and therefore energy at the front of the cylinder.
Actually, as I think about this just a little, it should be pretty easy to approximate if you can chronograph the first centimeter or two (millimeters would be better) of slide or bolt travel. For handguns, the energy loss should approximately:
Code:
1/2 {Mass of Slide} * {Velocity of slide} ^2
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energy lost to unlocking the action (probably negligible)
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1/2 {recoil spring constant} * {distance compressed for velocity measurement} ^2It seems the wild-card here would be energy used to unlock the action, but I'd think that would be extremely small in almost all cases. Am I leaving anything out?
EDIT: I've ignored energy lost to heat and static friction, obviously.
EDIT2: In some actions, moving barrels would lose energy here, too, based on their mass, distance moved, and moment of inertia. I'm going to go ahead and say this is on the order of "energy lost to heat" unless you've got a 5" threaded barrel with a heavy can on it.
This.
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But you're looking at energy used cycling the action. It only affects muzzle velocity if that energy would have been transferred to the bullet, if the energy would have been lost anyway...
(As long as we're going to discuss the details of a tiny amount of energy loss).
Good point! That's absolutely true, the energy used to cycle the slide would not have to come from the bullet, it could be from the bullet, from the muzzle blast (gases, flakes of powder, and sound), or lost to heat and light.
But I'd assert that it would be mostly from the bullet due to the large weight of the projectile, relative to powder flakes and compression wave. Without the projectile, will any semi-automatic actions cycle? Most (all?) handguns will not. If not, that's pretty good (although not totally conclusive) evidence where the energy is being traded from.
EDIT: I did a back-of-an-envelope calculation with random guesses, and got around 10 ft*lbs, or about the energy of a BB gun, or around half the energy of a .22 Short. I'm not sure what I think about that answer, it seems way high.
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wheelgun
NES Member
You have to look at the overall energy expended in the system. Energy must be conserved.
The fact that barrel and slide are locked doesn't matter here. A significant amount of energy is used to cycle the action against the force of the recoil spring. That energy drain reduces the muzzle velocity of the round. Even without the recoil spring, energy would still be wasted in accelerating the slide backwards.
An identical round fired from a bolt action rifle or single shot pistol with identical length barrel would therefore have more velocity.
ETA: This assumes all other things equal - i.e. amount of escaping gases etc.
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Length isn't the only consideration. Number of lands, "speed" of rifling (1 in 7, 1 in 14 etc), height of lands, surface material of bore, polygonal vs traditional rifling, barrel rigidity, and probably some other things I'm not thinking of all have an effect on velocity. The effect may be negligible, for the most part, but this is a theoretical discussion anyway unless someone wants to make up a couple hundred identical rounds to test with.
MisterHappy
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Far more energy is "lost" when there is a muzzle flash ( as the powder was not completely consumed while the bullet was in the bore ) than would be consumed by cycling the action.
Yes there is energy lost, but far more is "wasted" out the front.
As for actions using up energy, my primary Trap gun is living proof. I have the friction ring setup on my Browning A5 set for heavy loads. Most of the shells don't eject, and the recoil impulse is tiny. Still breaks the birds, though.
I'm not sure where I read it, but long ago one of the early gunmakers made a "machine gun" out of a lever action, by putting a cup in front of the muzzle to trap the gasses behind the bullet and cycle the lever. There was a prortusion on the lever to hit the trigger to fore the nest round, etc. Only problem was that it had to empty the mag once started! This is the only way ( except for an external power souece, e. g. Vulcan cannon) that you woudl not "lose" potential bullet energy to functioning the action.
Yes there is energy lost, but far more is "wasted" out the front.
As for actions using up energy, my primary Trap gun is living proof. I have the friction ring setup on my Browning A5 set for heavy loads. Most of the shells don't eject, and the recoil impulse is tiny. Still breaks the birds, though.
I'm not sure where I read it, but long ago one of the early gunmakers made a "machine gun" out of a lever action, by putting a cup in front of the muzzle to trap the gasses behind the bullet and cycle the lever. There was a prortusion on the lever to hit the trigger to fore the nest round, etc. Only problem was that it had to empty the mag once started! This is the only way ( except for an external power souece, e. g. Vulcan cannon) that you woudl not "lose" potential bullet energy to functioning the action.
I may be wrong on this, but my understanding is the barrel remains locked to the SLIDE until the bullet has left the muzzle. The slide/barrel have already started to move backwards together however so there is some (albeit an insignificant amount) of energy being bled away.
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