Tell me about firearm functions

I realise I've been making a lot of "tell me about" threads, but this one is of particular interest to me, as I have never been able to figure it out. It's been eating at me ever since BABs made his thread about Dual Handguns suggestions (and has since been relevant to this forum), in that he asked for a handgun that could shoot out a lot of bullets. I've been looking at handguns and their trigger mechanics and I can't, for the life of me, figure out which is which.

I could get into specifics, but since my knowledge is only second-hand, it will probably be wrong anyway, so I'll put my question in a much simpler form: Just how the heck do handguns operate? I've seen a lot of different designs, both for revolvers and semi-automatics, and there seem to be a few designs that I can't quite figure out.

Revolvers are easy - a drum holds the ammo, a spring-loaded striker in the form of an arm lever at the back strikes them to ignite them, and the trigger spins the barrel before it releases the striker... I think. It gets a LOT more muddy when it gets into semi-automatics of more modern times, though, specifically in the specifics of the "slide." This is where I ask the REAL question:

Why do some semi-automatics have a slide AND a striker, whereas others have only a slide? Are there semi-autos with only a striker and no slide, or would that necessitate them being a revolver? I've also heard of automatic revolvers, and heavens knows how THAT works. But this is primarily about slide-using automatic pistols and just how the heck they work.

Now, I just spent the last several hours reading through Wikipedia articles about gun mechanics. This isn't to brag, merely to say that just linking me to Wikipedia isn't going to help, since I was there just now. Also while there, I looked through a few different and much more technically fiddly aspects of weapons, specifically in the area of auto-reloading functionality. I have heard about recoil-operated auto-reloading, but have also heard that it is a deprecated technology replaced by gas-operated reloading. Except reading up on it now, it seems most modern weapons I'm aware of are reloaded via something called "blowback-operated" technology, with "gas-operated" being I have no idea what in the slightest.

This has been and on-and-off interest of mine that sees me occasionally reading through articles about it when I come across them, and the one that got me reading this time was an TVtropes that mentioned the Desert Eagle, explaining that it used "a rotating bolt like most rifles." Ignoring the fact that I was unable to find out what a "rotating bolt" was and what alternatives there were, reading up on the Desert Eagle shows it to have a striker separate from the slide, at least from what I can see. Which is surprised me, since I didn't think automatics had one, but I assumed they did and I just hadn't noticed. Which was a double surprise when I read up on "blowback-operated" firearms, which showed me a picture of the appropriately named "Colt Hammerless" pistol which... Does not have a hammer/striker visible outside the pistol. Hmm...

I actually have a couple of toy guns around the house, they're those plastic air pistols that shoot tiny coloured plastic beebee things, both seemingly oversized. One is a silver handgun branded 9mm, but which is apptoximately a foot long and has a striker. The other I recently discovered seems to be a Resident Evil wannabe prop, as it has S.T.A.R.S. engraved on both sides of the grip, is EVEN LARGER, much heavier (I suspect artificially, though it has a metal barrel to the other's plastic one) and, if I remember correctly, does not have a striker. I'll have to check when I get home.

Basically, and in all honesty, my question comes down to "What the hell, man? What the hell?" I've searched and looked and read up as much as I can and I'm still drawing a blank. Having never actually held a real gun in my hands, my ability to learn about them on my own is highly limited, so I'm hoping someone here is an enthusiast or an engineer or something, and wouldn't mind giving me a poor man's run-down.

Quote:

Originally Posted by Arcanaville Samuel_Tow is the only poster that makes me want to punch him in the head more often when I'm agreeing with him than when I'm disagreeing with him.

For the record, most game developers don't know either.

I don't know exactly what's giving you trouble Sam. Basically the slide uses the energy of that expanding gas from the cartridge to move back. There's a port in the slide that allows the empty cartridge to be ejected. A spring automatically pushes the slide forward, which allows a fresh cartridge to be chambered by a spring in the clip itself.

Pull trigger. Gas pushes bullet out and slide backwards. Spring ejects spent cartridge. Another spring pushes slide forward. Spring in clip pushes new cartridge into chamber. Repeat...

Any help?

That much I figured out, but it's the cocking mechanism (no snickering!) that has be somewhat confounded. As best I can figure, there is a pin inside the gun that strikes the percussion cap on a bullet's cartridge, but I've no idea how that works or how it's primed. A revolver is easy - it has a striker hammer that can either be manually pulled back until it locks, or one that travels back on a full press of the trigger if the gun has not been cocked previously. Where it all breaks down is why certain handguns seem to have BOTH a slide and a hammer, and how that even works. And why, for that matter, there are guns with only a slide and a smooth "back."

Then on the other side are the different trigger action setups, such as single-action, double-action and the variants in-between. It's explained in Wikipedia, but apparently it means something other than what I thought it meant, because I thought single-action pistols were the ones where pulling the trigger both ***** and fires the gun, whereas double-action were the one that had to be cocked manually (or was that the other way around?), but apparently there are variants on these that I honestly can't recall without reading up on it AGAIN.

And then there is the matter of high-powered, large-calibre handguns having mechanisms more akin to rifles than to pistols, which goes into territory I'm not in the slightest familiar with. Again, the Desert Eagle .50 Action Express, possibly THE large gun of fiction, is said to use something called a "rotating bolt" that is said to be more like a rifle, but I've no idea what a pistol would use by contrast, so this bit of info is completely useless to me. Specifically since I don't know what a rotating bolt is, either. Or, to be honest, exactly what a "bolt" even is, as it pertains to firearms. I know what a bolt action mechanism is, but since the term seems to be used for self-loading guns which cannot, by definition, be bolt action, I've no idea what it actually stands for.

Basically, this is a question of technicalities in case someone feels benevolent and wishes to educate a complete fool in this particular field a bit

P.S. And this must be some kind of record... A whole post without a single word that Fire... That "my browser" doesn't recognise

Quote:

Originally Posted by Arcanaville Samuel_Tow is the only poster that makes me want to punch him in the head more often when I'm agreeing with him than when I'm disagreeing with him.

I'l help you out as best I can Sam.

The ones with just a slide tend to be smaller, and are usually a small caliber. The fact that they are smaller means there is not as much tension on the spring in the slide. Meaning that it doesn't take as much physical strength to pull the slide back and **** it.

Generally, larger caliber and larger bodied automatics have an external hammer as a way of cocking the gun for those who lack the arm strength to pull the slide back, as larger guns usually have much larger springs that require some muscle to move. If you've ever tried to **** a 1911A1 Colt .45 using the slide you know what I'm talking about. The hammer is there so anyone can use it regardless of their physical strength.

Look again at the examples you were looking at. You should find that the majority of the semi-autos that have external hammers are also large caliber guns, and are probably rather large physically.

Edit: That's pretty funny that you can't use the common term for readying a pistol to be fired without the censor kicking in.

there's a show on History Channel called "Lock n' Load with R. Lee Emery" that i think has some good answers for you as they get into the entire evolution of fire arms and other weapons and explain the basic mechanics of it as well. each episode they start with the original historical model and work their way up to the modern day equivalant with certain benchmarks along the way. it's about to be released on DVD unless you have other sources.

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Sam,

"Gas Operated" and "Blowback operated" are basically the same thing. When the trigger of a gun is pulled, the bolt or hammer sends the firing pin into the blasting cap of the cartridge (bullet), igniting the powder inside of the cartridge and sending the bullet off. The kinetic energy from the explosion also sends the bolt or hammer back, re-cocking the gun and readying the gun for the next shot. In fact, semi-automatic pistols aren't far removed from submachine guns or machine guns.

You can find more info on gun recoil systems here.

As far as I know, Single Action and Double Action is only used in revolvers. The double action revolvers (which I understand is the norm nowadays) did two things when you pulled the trigger. They rotated the cylinder AND they pulled the hammer back so you could shoot again.

With the single action revolvers you had to manually pull the hammer down. This resulted in the special maneuver called "Fanning the hammer" for rapid fire.

I knew that those Deadlands books were useful one day besides playing the game

Everyone else has covered most things, but I want to specifically point out that "hammer" (the lever on the back) does not necessarily equal "striker" (mechanism that mechanically activates the firing cap). That's the way it used to be, and still is on simple revolvers as seen with the pin jutting from the hammer here. On more modern handguns the hammer may be simply a convenient lever for both cocking and uncocking the weapon, and while mechanically associated with the firing-pin-release, is not the striker itself.


A "rotating bolt" in an automatic weapon is actually a derivative of the old Bolt Action that you looked up. There you had a lever arm that you rotated and "locked" into a slot in the housing to secure the bolt in place for firing. You rotated it back up so you could open the bolt and extract the spent round.

In the sense of a modern automatic, it means that when the spring sends the bolt back forward, it "rotates" slightly after meeting the back of the firing chamber and "locks" itself into it.

The point of this is to get more energy out of the explosion. If the bolt doesn't lock, then it is just the expansion of the brass cartridge casing that prevents it from traveling backwards immediately. This is actually why brass is still used for cartridges today: it will expand with the explosion and "seal" itself against the sides of the chamber, preventing any gas from escaping around it and sending all the energy into pushing the bullet out of the barrel. As soon as the pressure drops just a bit, the brass cartridge shrinks back down and unseals itself, allowing the expanding gas in the barrel to now push it backwards as well as the bullet forwards.

If the bolt locks itself into place, then how long the pressure is kept at a maximum isn't reliant on just the expansion of the brass. You can send the bullet farther forwards before part of the expanding gas (harnessed in dozens of ways depending on how the mechanism is built) mechanically forces the bolt to "unlock" and start pushing it backwards.

Most handguns *don't* use this kind of force-maximizing method because less of the initial recoil is absorbed by the action-spring and goes into the weapon itself. That's not such a big deal with a large-mass rifle that expends its recoil energy into your upper body-mass, secured by both your arms. It matters a lot more in a low-mass pistol-sized weapon wherein what force isn't expended in overcoming its smaller inertia goes entirely into your wrist =P. So for most handguns, "losing" energy by allowing it to be expended early into the slide-spring is just fine. The Desert Eagle Fifty-Cal is a special case and has too much machismo to be concerned with trivialities like carpal bones or joint cartilage...

Ok, I'll start with some simple definitions:

Single action revolver: a revolver where the trigger pull is generally light (3-7 lbs) and will only drop the hammer and fire the weapon. It will not revolve the cylinder or push back the hammer. You have to retract the hammer using your thumb (or whatever) which also revolves the cylinder. An example of this would be a Colt 1873 Peacemaker.

Double action revolver: in this case the trigger pull does all of revolve the cylinder, pull back the hammer, and then drop it. The trigger pulls are generally fairly heavy (12+ lbs). Pretty much every modern revolver is like this (Colt Python for example).

Single action pistol (pistols are different than revolvers). This is generally on a semi-automatic weapon where the weapon is loaded by pulling back the slide which sets the hammer and loads the weapon. Then the trigger pull just drops the hammer. Then recoil from the weapon firing which run back the slide, eject the spent cartridge, load a new cartridge, and set the hammer for firing again (actually in some rare pistols the mechanism is gas operated rather than recoil operated, but the difference is in the inner workings and academic here). Pistols of this sort will continue to fire per trigger pull long as there is ammunition in the magazine. Examples: Colt 1911 , or Ruger 10/22. On a defensive firearm you will carry this sort of pistol c0cked(been trying to dodge that word) and locked which means hammer back and safety on.

Double action pistol: This is a semi-automatic pistol in which the hammer is drawn back by use of the trigger before firing. After the first round is fired, the weapon will generally go into single action mode where the hammer is back from the previous shot and only a short, light trigger pull is required to fire the weapon. Again firing will continue with trigger pulls as long as ammunition remains. There is a variant of this type of weapon which some people favor called the double action only (DAO), in which the hammer does not remain back when the weapon is fired and you need a double action pull for each shot. This is desired by some because it makes the trigger pull consistent for all shots unlike in a normal DA pistol where the first shot has a much heavier trigger pull. Most double action pistols will have a dec0cking level which allows the hammer to be lowered safely after loading so it can be carried with a round in the chamber. Examples of DA pistols are Sig Sauer P220, or Beretta 92F.

Ok, then you have some other variants. The main example of this would be the Glock (and some other imitators). It is a semi-automatic pistol using no exposed hammer. The striking mechanism is all internal. These will generally have a heavier trigger pull than a single action, but less than a double action (sometimes called 1.5 action).

Of course the above doesn't explain why sometimes there are exposed hammers and sometimes not. Well in every case there has to be a mechanism of some mass which strikes the firing pin and ignites the primmer. On most guns this is the hammer, while on the Glocks it is an internal mechanism. Why did Glock decide to design without a hammer? Well there are advantages in keeping a mechanism enclosed to avoid modes of failure from external sources. Also a hammerless gun will not snag on clothing if carried in a pocket or during a draw.

As for firing mechanisms, which I think you are curious about (hence the Desert Eagle question), there are only three mechanisms in semi-automatic pistols I can think of. There's the simple blowback mechanism where recoil simply slams the slide back against the recoil spring thereby ejecting, loading and resetting the hammer. The barrel is generally fixed to the frame. This was the first system in use, and is generally too hard on a pistol for any heavier calibers. It is rare to see it on anything higher than a .380 (9mm kurz) because the slamming back to the slide stops would be hard on the mechanism. An example of this would be a Walther PPK.

The next is the short recoil operation. This involves the barrel and slide both being mobile during the initial recoil with the barrel being locked into position after a short bit of travel. Then the slide continues back to finish the operation of reloading. This spreads the recoil impulse out over more time and parts making it easier on the mechanism. Most pistols these days use this method of operation.

The last, and least common method is the gas operation system. I can only think of two pistols where use this system. The Desert Eagle, and the H&K P7. In this case a port exists on the barrel by which some of the ignition gasses are shunted into a chamber where they push back on a piston which drives back the slide. Gas operation systems are very good for mitigating recoil (hence it being used on the Desert Eagle which fires a very powerful .50 caliber round). However they are harder to manufacture and clean so are not popular.

There are other mechanisms used in rifles, but we don't need to go into all that.

>.> <.<

Further into the realm of "more info than is really necessary", but there is a fourth type of semi-automatic pistol action which was very popular in its day. The German Luger P08 uses a "toggle-locked" operation to disconnect the barrel from the rest of the toggle-assembly (for lack of a better term) as it recoils. I don't know of any other pistols that use it but it was very successful on the Lugers.

/w

See, I KNEW this would happen I knew that there would be people here with extensive knowledge of the subject, who could present it much more logically and comprehensively than any encyclopaedia I've seen. And I was right. So far, I love what I'm seeing like you cannot believe. One of the things I enjoy most in life is understanding things. It doesn't matter what that thing is, as long as I understand it, I'm a happy camper. In this case, weapon operations keep coming up time and time again even just in idle conversation here, and knowing about them will really help me make sense of discussions, as well as actually make sense of why guns look the way they do.

A few things I've picked up so far:

I do not know what a "bolt" is, exactly, though I have a few guesses. If I had to give my best one, I'd say it's the part which seals the back of the barrel during fire to confine cartridge gasses and direct the actual bullet forward, hence why an automatic's slide also technically works as a bolt. I think...

I love the purely verbal mental image of the slide sliding back and "scooping up" a new round to chamber. I don't know why, but I always kind of thought rounds were forced up by a spring in the magazine, and I mean ALL the way up into the barrel. As it stands, it seems like they're forced up just high enough for the slide to push them into place.

The hammer on an automatic only controls the striker, but does not have the ability to chamber a round, so inserting a new magazine would still require a slider pull. I'm not sure if that would require a slider pull all the way back or not, but just cocking the hammer and pressing the trigger would not produce a shot.

Double-action automatics do exist, but the double action only sets the hammer and does not move the slide or chamber a round. Which kind of makes sense, given how solid the recoil springs really are.

A rotating bolt is a bolt similar to that of a bolt-action rifle, in that it locks itself into the chamber and requires, I assume, some degree of has pressure to overcome, thus maintaining a tight seal longer. This is used to impart more energy to the escaping bullet, but comes at the cost of recoil into the body of the gun, and so into the shooter's body.

Most contemporary guns use a recoil-operated mechanism to operate their auto reloading, essentially allowing a part of the gun to be forced back, which animates the rest of the gun. Gas-operated weapons, instead, use a gas chamber and piston to do the same thing and, I assume, rely less on heavy recoil springs.

Automatic handguns remain half-self-loaded with the slide back, so that chambering a round is easier upon inserting the next clip. Instead of requiring a full draw on the slide, they just require that the slide be released forward, chambering a round and cocking the striker. Clever. The mechanism for achieving that, exactly, doesn't seem like it's too important, but the mechanism for releasing the slide might actually be.

Single-action revolvers need to be manually cocked every time, but can be fired really quickly by fanning the gun, just in case you weren't interested in actually hitting anything with the bullets you fire. Double-action revolvers do all actions on a single, heavy, long trigger pull, making the gun completely automatic, but making firing it repeatedly look like you're squeezing a lemon in someone's face. That explains why people firing revolvers in old cop movies looked so dang ridiculous.

I'm still not sure what the heck a semi-automatic revolver is, but I know at least one exists. It may not be very important for real-life purposes, but ESPECIALLY for the sake of Dual Handguns weapon customization, it would be fairly important, specifically to satisfy BABs' requirement that the gun can shoot many bullets in rapid succession. This feels like the Pancor Jackhammer of handguns. Who cares if it's not a large-scale commercial success?

I'll have a look at the "How Machine Guns Work" (interesting topic, even if I couldn't spin it as being relevant here ) tomorrow. After spending two and a half hours with no power, waiting in the dark, I have a few things to take care of today, and it looks like it's a big read.

I actually think I understand a lot of what I was looking for right about now. I'll see if I still remember it tomorrow, but I feel like I'll be re-reading the thread several times over just to freshen up. I've never used a gun, and I doubt I ever will unless civil war breaks out here or something, but damn if I don't enjoy guns in video game. It's like the 90s kid said: "He's got the coolest super power of all, man! Guns!"

Quote:

Originally Posted by Arcanaville Samuel_Tow is the only poster that makes me want to punch him in the head more often when I'm agreeing with him than when I'm disagreeing with him.

Docbuzzard provided an excellent summary in his post, which covered most of the basics of the mechanical operation of firearms. I don't really have anything to add, but if any of my CoH brothers and sisters are located in South Florida, and are interested in getting any hands-on experience with firearms, I'm a certified law enforcement firearms instructor, and would be more than happy to arrange something for them.

*Mandatory disclaimer: The above does not apply to convicted felons, the mentally incompetent, or to those under the age of 18, unless accompanied by a parent or legal guardian.

Here is a link to an excellent animation showing the mechanical operation of a 1911 type semi-automatic pistol. You can toggle off the various external parts of the firearm to better show the internal operation.

http://www.m1911.org/loader.swf