Some of the common calibers of guns are .22, .357, and .38 to name a few. IANAFE (firearms expert), so I don’t understand the use of these seemingly arbitrary values. Why not the same standard nuts and bolts sizes like .25, .375, .5 and so on?
And while I’m on this topic, what does “thirty ought six” mean? If it’s .3006, why not just .3?
The “Ought Six” part had to do with 1906. The year the cartridge was developed. The 30 is the caliber.
A little info 30-06 in this article.
Not sure about all the others.
Depending on the need of the user, different bullets are needed for different tasks. A .22 will dispatch a ground squirrel easily, but will not significantly damage a bear. For that need a larger bullet/cartridge combination is required. Peopl are always trying to eek out more performance than what is currently on the market, kind of like hot rodding cars. For the most part however, there is a standard set of calibers. After that, there are the “wildcats” or cartridges that have been created by a home user or manufacturer to meet a specific need or to increase performance on existing combinations.
Every now again, a newcomer will break into the market. The .17 HMR was a joint effort by several gun manufacturers and a bullet maker to make a rimfire round that exceeded the standard performance of the .22 cal. so far it is doing quite well.
Others, like the 10mm pistol round were created and never really caught on with the popularity that the 9mm or .45 cal already had. There will always be diehard lovers of any particular bullet, they will usually continue to handload after factory ammo is no longer available.
Cartridges pick up common names that don’t always follow the same conventions. It’s true that a .30-06 refers to a .30-inch diameter bullet in a cartridge load developed in 1906. But a .45-70 refers to a .45 inch diameter bullet that was originally loaded in a cartridge with 70 grains of black powder.
Even with standardization, the sizes would need to be in much finer steps. Compare .22 caliber to .25: it sounds like a more or less trivial difference, but if two bullets were of the same material and shape, the .25 version would weigh almost 47% more than the .22 bullet - a significant difference.
But it’s sort of like bicycles, or knives or screwdrivers - there’s always someone who thinks he has a better idea and likes to tinker. Most such experiments lead nowhere, but obviously more than a few have caught on. So even if we started with a limited number of basic sizes, we’d soon see more.
Along that same line, the 30-30 is a rifle that uses a .30 inch diameter bullet in a cartridge loaded with 30 grains of powder.
Also, the .38 and .357 are the same diameter; the .357 is just a longer version with more powder and more oomph. This is why the vast majority of .357 pistols will happily eat .38 ammo. The reverse doesn’t apply. Naming the round .357 was somewhat arbitrary, as the developer wanted something “cool” and unique, rather than calling it a .38 Magnum, which would be more accurate.
Speaking of guns…
On CSI Miami last night there was a plot line regarding the cocking of a hand gun. Why would one need to cock a gun in the first place? Most hand guns simply are pointed and fired. Are only certain types of guns “cockable?”
Pardon my complete ignorance, but I’ve never seen a hand gun, and have only seen a real-live rifle once.
It’s the other way around.
A nominal .38 measures .357.
???
Doesn’t the “0.38” imply 0.38 inch diameter? Wouldn’t “0.357” imply 0.357 inch diameter ammunition? Isn’t that a significant difference? (That could possibly get someone killed)
Or is this something where the actual figure doesn’t mean what it appears to – as with “2 X 4” lumber or " 1/2" format CCD"?
That’s fine, but I think it misses the point of the OP – Why, in fact, are the numbers so bizarre? Why not have calibres in increments of 0,.02 inch, or something?
Doh! You’re right. Good catch.
Nuts and bolts evolved from blacksmithing and carpentry, where fractional inch measurements were traditional. so sizes like 1/4" 3/8" etc. made sense.
Modern firearms come from a machine shop traditon, where decimal measurement
is the norm. So sizes like .3 .25 etc make sense.
Guns developed both in the metric measurement world, and in the imperial measurement world, but not independantly. It’s hard enough developing a new gun. If there is already a supply of bullets available, it saves a lot of hassle even if you have to import them initially.
So 7.62 (millimeter) Nato rounds seem odd, until you realize this is .30 (inches) caliber.
.357 seems an on caliber…but 9mm is a nice round number.
.270 isn’t an even number, but 7mm is.
Rifling throws another variable into the mix. Rifle and pistol bores are grooved to spin the bullets. (required for stability) Do you specify the minor or the major diameter? This explains why .30 caliber is also known as .308 in some cartriges.
And, in the vernacular, how many decimal places do you keep? Many calibers are known by a rounded version of thier actual caliber.
Many calibers, and more cartriges have become extinct. The survivors either worked well for a particular purpose, Worked OK for LOTS of purposes, or were the common caliber of one or two particularly popular guns. Gun manufacturers sometimes develop a"new improved" caliber as a marketing ploy. (to be fair, these often do have tangible advantages)
So that is caliber, which only discribes bullet diameter. When laded into a cartrige, you need a unique name so that customers can communicate thier ammunition needs to the sales clerk at the gun counter. It needs to be easy to remember, and hopefully a marketing tool for your company. If the round becomes very popular, it will probably aquire som aliases on it’s own, and the origional name may fade to obscurity…such as:
.308 Winchester = 7.62 Nato
9mm Parabellum = 9mm Lugar = 9mm Nato.
.38 police special = .38 special
Sometimes the names make a ton of sense. If you neck down a .30-06 case to .25 caliber, then .25-06 is a pretty reasonable name for the new round.
The term “Magnum” nearly always discribes a much higher powered dirivitive of some previously existing round, though Weatherby in particular may vilolate that convention…and sometimes the souped up round gets an entirely new name.
some examples:
.357 Magnum = souped up .38 special.
.44 magnum = souped up .44 special.
.454 Cassul = souped up .45 Colt.
In all of the above cases, the case is made slightly longer so that it will not chamber in guns not designed for it. Most of the extra power is gained by using modern smokeless powder to fill cases origionally sized for lower energy black powder.
Revolvers generally are “cockable”. Revolver actions come in two general flavors: single-action and double-action. Single-action revolvers are either very old or very cheap and you don’t see too many of those around. To fire a single-action revolver, you must cock the hammer back before to fire it.
Double-action revolvers are the great majority. You can either fire the revolver cocking the hammer beforehand or by just pulling the trigger (harder) to automatically pull the hammer back and fire it. Most of the time, you would just pull the trigger and fire but there are reasons why you would want to cock the hammer first.
Do some, most, or all “automatics” need to be cocked first, too? For instance, it looks to me that the M-1911 Colt .45 automatic needs its knurled hammer cocked before firing the first shot and only the subsequent shots are cocked automatically.
There are also DA only revolvers. The spur required for cocking the hammer is a liability (it can snag clothing) in some concealed carry situations. Many compact revolvers are available in both versions.
Many automatics can cocked as well. This happens automatically when the slide is cycled to chamber the first round. Many can then be “de-cocked” which may be safer condition for carry. Automatics were historically single-action only, and so would then require cocking in order to fire. The M1911 .45 is a prime example.
Double action automatics are relative newcomers, and will fire from either cocked or de-cocked condition. If fired from de-cocked condtion, the first shot has much heavier trigger pull than subsequent shots. While an impediment to accuracy, this can arguably reduce inadvertant discharge. in for example, law enforcement situations. The US militarys 9mm Baretta is a classic example, but the genre is widespread.
Finally there are double action only automatics which neither require, nor permit cocking. Glocks and a few others fall into this catigory.
There are modern production SAs that are far from cheap. Some are made for SASS competition (AKA cowboy action shooting). Some are very large caliber. Lacking the loading crane (or the hinge and latch of a Webly) a single action frame can be made much stronger for a given weight. Also, since the alignment between barrel and cylinder is fixed, the cylinder/barell gap can be reduced, and the forcing cone made shorter…resulting in less bullet shaving, powder burns, and slightly improved accuracy. Freedom Arms is a prime example.
It WOULD be possible to have all of these advantages in a DA if SA style one-at-a-time loading and half-cock notch were adopted. To my knowlege, however, there are no examples of such.
I did not realize that. I guess there is a niche for everything.
I’m not a gun guy but cocking or not in handguns is the difference between a single-action and a double-action gun. With single-action the gun is cocked manually, with double-action pulling the trigger cocks the gun and also doesn the firing.
One reason for single-action is, I think, for accuate shooting. With it the trigger pull can be made exceeding light and with very little motion of the finger so as to not disturb the aim; the so-called hair trigger. Double-action requires less action on the part of the shooter in situations calling for rapid fire. And, of course, the mechanism for a single-action run is simpler than for double-action.
Firearm ammunition sizing is full of anachronisms owing to historical development and changes in technology. A good example is the .38 Special/.357 Magnum issue. The original .38 “caliber” rounds were “externally heeled”–that is, the base of the round was flush with the outside of the case, hence the bullet was nominally .38 inches in diameter. This was a carry-over from muzzle-loaded weapons where there was no case and the chamber was the same diameter as the barrel. (In currently used rounds, this can be seen in the .22LR and .22WRM cartridges.) In later firearms, the chamber came to be bored out, allowing the bullet and bore to be a smaller diameter than the case, and the bullet came to be fully seated inside the case. Because the case was the same diameter, the .38 S&W and the .38 Super Police (not to be confused with the .38 Super), and later the modern .38 Special continued to be known and nomenclatured as “thirty-eights” even though the bullet diameter is actually .357-.358 inches. When Smith & Wesson developed the .357 Magnum, they used the “correct” size because…well, probably because it sounded cooler, and more to the point from a marketing point of view, was distinct from the .38 Special. The case is IIRC 0.125 inches longer than the .38 Special, not because the extra space is needed but to prevent the round from being loaded into the weaker guns chambered for the .38 Special, permitting one to fire the .38 Spl in a .357 Magnum revolver (though resulting in chamber fouling if this is done frequently) but not vice versa. Note that this is not generally the case even with bullets of the same round; a 9mm Kurtz/.380 ACP round should not be fired in a 9mm Parabellum (9x19mm) pistol, nor should any of the more exotic 9mm rounds (9x19mm, 9x21mm, 9x22mm, 9x23mm, .356TS&W, .38 Super, 9mm Glisenti, 9mm Bergmann Bayard) be fired interchangable with each other, even if you can force the pistol to chamber the round.
The various .30 “caliber” rifle rounds that are common in the US are mostly around .307-.309 inches in diameter. For the most part, Canadian and European-designed rounds whose “calibers” are measured in millimeters (6.5mm, 7mm, 9mm, et ceter) are generally very close to their nomimal values, but the American-designed 10mm Auto is actually .400 inches in diameter, which makes it 10.2mm. (The subsequently derived .40 S&W, originally and dispairagingly referred to as the “10mm Short” during development) is actually correct, as is the .400 Cor-Bon. The .357 Sig round (a .40 S&W case necked down to accept a 9mm bullet) is, like the 9mmP, actually .355-.356 in diameter but is so named to for marketing appeal to law enforcement as a high capacity autoloading replacement for the venerated .357 Magnum cartridge.
By the way, the term caliber does not always refer to bore size; in naval and artillery guns, it referes to the ratio between the length and bore. Gauge, in terms of shotguns, is a measure of the number of balls of equivilent diameters to the bore that would measure up to one pound of lead, which is why shotgun bores get larger with decreasing bore.
So, the reason that the sizings of small arm calibers isn’t specifically because they are arbitrary, but because they were developed by different parties with different standards and/or marketing strategies. There’s really no physical reason, strictly speaking, that a suitable selection of rounds couldn’t be made in standard increments–say, in .05 inch or .5mm increments–with bullet weight, profile and ogive, case configuration, and powder capacity tuned to suit each application, and indeed, this is the case for the proliferation of most modern “wildcat” (custom) rifle rounds which use standard bullet sizes and custom cases–but historically each round was developed at different times, by different people, for different purposes, with no need to commonize on tooling, hardware, or sizes. Today, certain calibers, and within them, certain specific rounds have been winnowed through experience to become the most widely used, with a minority of shooters selecting niche rounds for very specific purposes (or because it’s just cool to shoot some round no one at the range has every heard of) leading to minor but dramatic “religious” arguments regarding caliber selection.
Then there’s the debate among Computer Science graduate students as to what the best round for surviving grad school is; you know what they say: “The tragedy of Galois is that he could have contributed so much more to mathematics if he’d only spent more time on his marksmanship.”
Stranger
I’m not sure what DA revolvers you have experience with but I’ve never seen lead shaving or had a problem with cylinder gap in a gun that wasn’t damaged or worn out. Some revolvers such as the WWI era S&W triple lock and the Dan Wesson have a locking lug at the top of the crane but even on guns that only lock at the rear of the cylinder lead shaving is virtually never a problem in quality guns.
Cylinder gap doesn’t exist because of alignment problems but to keep the cylinder from binding up because of powder fouling. Black powder revolvers require a larger gap than with smokeless propellant. I shoot reproduction Colt’s revolvers which have a variable gap and no topstrap to avoid this problem with black powder but with proper lubricant I can keep mine set to a minimum gap. Dan Wesson’s interchangable barrel system allows the cylinder gap to be set by the user. I always kept mine set to eight thousandths and never experienced lead shaving.
Reducing bullet jump - the distance the bullet travels from the cartridge in the cylinder to the forcing cone in the barrel - can improve accuracy but this is a function of the overall length of the cylinder with the gap being a tiny portion of that distance.
Oh, there were lots of revolvers with double action, solid frame and a side loading gate from H&R, High Standard and others. Most of those were expensively made than better revolvers from S&W and Colt’s and consequently some had lead shaving problems.
RE: the OP calibers are often speficied in two ways, by bore diameter or the larger groove diameter. Inch calibers, typically used in the US use the groove diameter which is the same as the nominal diameter of the bullet. Metric designations commonly used in European calibers usually use the bore diameter which is several thousandths smaller than the bullet diameter.
Cool! I had no idea. So why does the ratio between length and bore get a unit of measurement? (i.e. 155 mm or 16")
Those measurements, if you are referring to howitzers and main guns on a Missouri class battleship, do not refer to a bore/barrel length ratio but to projectile diameters.