What is Calibre?

[BLUEHAWK]

:cd:

Okay, now you infantry are REALLY gonna make fun of me...

What exactly IS calibre? I mean, how is it measured, since there is also millimeter (mm) sizes that are talked about.

Are mm's and calibre the same? If so, then why not just use one or the other?

What is the smallest calibre or mm?

What is/was the largest ever? (I mean like Navy battleship 16 inchers etc)

Does EVERY possible shell have either a calibre or a mm?

When did these type measurements get started in history?

Is there any OTHER type measurement unit that is or ever was in use?

Did cannonballs have calibre or mm?

:af: (I put this in here so you would not think I was afraid of guns)

[Keith_Hixson]

the diameter of the bullet (slug).
The Old English System 30 caliber
Metric System 7.62 mm

Same thing: ie 7.62 Nato or 308 Winchester same bullet.



A 7 mm slug would be a slightly smaller diameter slug than a 30 Caliber slug.
A 8 mm slug would be slightly larger than a 30 Caliber Slug.


For instance: the 30-30 Winchester, 30-06 Springfield, 308 Winchester all shot 30 Caliber Slugs / Bullets.

I hope this helps.

I am not an expert on this subject all shooting weapons have calibers. Weather it is a cannon or twenty-two.

Most modern firearms shoot the 22 Caliber as the smallest Caliber .
.223 Which the M-16 uses is a pretty small caliber
.222 Swift another long shooting small caliber bullet.

I believe (not sure) there are some bullets in the .184 Caliber area.

Sid and Col Murphy know much more about firearms than I do but I hope this helps.

Keith

[BLUEHAWK]

Keith -
But bullets have variable diameters depending on where you measure. Do you measure which end or section?

So, what you are saying is basically that american bullets would be measured in calibre, and other countries (like Britain and european) would be measured in mm?

Do mm bullets fit into calibre rifles?

Its confusing because in my good ole USAF toolbox I learned that mm wrenches DO NOT fit inch-wise nuts and bolts.

From where did these calibres 30-30, 30-06, 308 etc come from, I mean what is the difference between 30-30 and 30-06 for example?

[Keith_Hixson]

1. The hole in the barrel of the rifle (BORE) or pistol, etc is the caliber. The way the slug goes through the barrel is the way you measure the caliber of the bullet.

2. 30-30, 30-06, 308 will all shoot 30 caliber bullets. The difference is the brass casings and how much powder the brass casing holds. 30-30 has a much smaller brass casing than than the 30-06.
However, the 300 Winchester Magnum is also a 30 Caliber Shell.
But it has a much larger casing than the 30-06.

The 30-30 will have a drop of lets say (just guessing) of 16 inches at 600 yds.
The 308 Winchester 12 inches, The 30-06 10 inches, and the 300 Winchester Magnum 8 inches. The larger the brass casing the more powerful and longer shooting the cartridge.


Now, Caliber basically means the size of hole in your barrel or the diameter of the bullet the way goes through your barrel.

.308 is the English measurement of a caliber
7.62mm is the metric measurement of the same caliber.

You are correct that one is metric and the other English measuring system. But both are calibers or diameter of the bore of the barrel.

Now I know Sid and Col Murphy could do better at explaining all of this. I'm a hobbiest not an expert.

One: piece of ammunition is exactly the same:

308 Winchester is exactly the same cartridge as
7.62 NATO Cartridge. No difference that I know of.

7.62 mm bullets can be shot in .30 Caliber Rifles and vice versa its just the measuring system that differs.

Keith

[colmurph]

The British use Lbs. to measure caliber in cannon ie: 24 pounder which would be about 6". We use caliber measured in hundreths of an inch for small arms up to .50 Cal. (1/2 Inch) however we revert to millimeter for everything larger ie: 20mm 37 mm 105mm 155mm but then we fall back to inches for the 8" howitzer then go back to milimeters for the 175 mm and 240mm. Makes a lot of sense huh? The Navy on the other hand uses inches only, ie: 3" 5" 8" 16" but to that they add caliber! as in 5" 38 Cal. In this case the caliber refers to the length of the rifled portion of the barrel. In the case of a 5 inch 38 caliber this would mean that the barrel was 38 times the bore diameter long or 190" long or 15 feet 10 inches. Confusing isn't it? The smallest caliber I ever heard of was a 4mm Kholbri. This bullet was only good for shooting something like a sparrow. The largest I have seen was one that was an 800 mm German Mortar Shell. They have one at Aberdeen and the brass casing is big enough to take a bath in.
The smallest commercially manufactured bullet today is the .17 cal Bee, a wildcat round. (For comparison to diameter, a BB shot is .177 caliber)

[BLUEHAWK]

Keith and Murph -

Amazing, absolutely amazing... I obviously had no idea at all.

Thanks

[PHO127]

There is a variance between lands and groves of some of the same diameter bullets. For instance a .308 caliber bullet is .308 from land to land of the rifle (or 7.62mm) but the grove in the rifling can be different. an AK 7.62 rifle has a deeper grove in the rifiling than a NATO 7.62 therefor the bullet loaded in an AK round is a .311 diameter bullet rather than a NATO 7.62 round which uses a .308 diameter bullet. Also, the designation for ammunition may be such as 7.62 X 39 which is an AK round with a 39 mm case length, versus a 7.62 X 51 which is a NATO .308 or 7.62 with a case length of 51 mm or a Russian 7.62 X 54 which has a case length of 54 mm but is a rimmed case. Confusing, just wait, The black powder ammunition is designated with the bullet diameter such as .44 caliber and the grains (weight) of black powder in the load such as a 44-40 or 45-70. 40 or 70 grains of black powder in the load. Then there is the good old american standby the 30-06. 30 caliber adopted in 1906, originally was the 30-03. then the customs and wildcats, custom bullet loads named after the developer such as a .416 rigby or black powder double rifles such as the .500 or .600 nitro express. The wildcat ammo for custom shooting such as a such as a .308 phoenix. When I started learning how to load my own ammunition I found out that you almost have to be a PHD in physics to figure out how to load and what to load.

[BLUEHAWK]

Pho -
Which is one reason I've never gotten started with it...

Thanks for the info!

[Keith_Hixson]

I have several friends who play around with reloading. Just because you make bullet "hot" doesn't make it better. Some loads will produce great accuracy and others will produce loose flying bullets. Most serious reloaders experiment, and experiment and experiment some more before they get their favorite load to be absolutely accurate.

Keith

[BLUEHAWK]

Guys -
I guess the whole deal for me is that most who've never been in combat or service for that matter, probably think that all you do is get issued a weapon, then some ammo, and then you go shoot people.

The better fighter, it would seem, is the one who understands their weapons the best. Maybe not always, but that fighter would have the better chance of completing and surviving just about any given mission, and also being better able to lead/teach his buddies... some of whom will be just like me; never saw a rifle until basic training, fired exactly one clip of ten rounds at the range (almost made M-1 Expert though!) after half a day of indoctrination , and then never saw another one.

Watching our guys on film or video from all these wars, tells next to nothing technical about their skill and knowledge, to american civilians. We take such pride in our military, most people do anyhow, I'd just like to put myself in your shoes a little bit is all, and the only way I can do that is the way I do everything else... ask a lot of questions, and learn to duck.

Hopefully, one day I'll be able to offer something intelligent when somebody starts spouting off about their opinions concerning what battle is like for the gunners.

[revwardoc]

I knew a guy in CA who used to load his own ammo. One day we were out in the desert to experiment with some of his loads. He handed me his .44 Magnum and a bullet. He kept very meticulous records, even filming (I believe it was 8mm film) every test shot. I loaded that hand-cannon, aimed, squeezed off the round, and ended up on my butt looking up at the sky. My shoulders felt like I'd just tried to stop a bus with just my arms. He walked over to me, making notes in his book and said, "Hmm! That may have been a bit much! Let's try this one!" I told him I'd try again only if he were the target. When the film was developed I was amazed at the power of that one shot. The 2' high weeds in front of me were laid almost flat from the shock wave and the flame out of the barrel was clearly visible. I told him to, next time, just toss me a live grenade, I might have a better chance!

[PHO127]

Bluehawk, Actually, by far the greater percentage of combat soldiers are not that expert in knowing the full capabilities of their weapon. One of the reasons that the Kalishnikov type (or AK) weapons was and is so popular is that it took little care in the field and would shoot 99.99 % of the time. The AK type weapon is manufactured with wide machining tolerances on its parts therefor it fits together somewhat loosely and can take a lot of abuse such as dirt and non cleaning and still fire. They were made with a very uneducated soldier in mind and therefore had to be simple and easy to use. The U. S. on the other hand made a very fine weapon with the M1 and even better with the M14 as main battle arms. But these rifles were large, heavy and difficult to use in a jungle. The development of the .223 remmington round and mating it with the AR-15 type rifle (M16) was the dream come true. A very well built rifle with a very devastating round. Then came the problems. The M16 was a fine precision built weapon but had very close tolerances on its machining and required a lot of care. It would not tolerate a lot of dirt or lack of cleaning and would jam up. I am guessing, but I would say that in VN less than 10% of the small arms fire was aimed fire. 90% was just spray into the brush or jungle. The important part was to lay down a base of fire and not so much that it had to be aimed. The reason for this was that we were engaging at very short ranges and most of the time not able to see but maybe 1 or 2 of the enemy. We needed a lot of bullets in a small space, What the Calibre, MV or anything else about the weapon was not important as long as it would fire. At the other end of the spectrum are the precision shooters or snipers, They know everything about their weapon. The really good ones can shoot man sized targets in excess of 1,000 meters with a .308 calibre rifle. They use custom (or special manufacture) made rifles with custom made ammunition, and high quality optics. At 100 yards they can put three .223 bullets into a target the size of the pupil of your eye.

[BLUEHAWK]

Dan -
> If there is just so much room in a cartridge, then in what manner can one add too much of something, and what is that something that one adds which would knock you on your butt and lay weeds down ahead of the shot?

Pho -
> I see what you are saying, about relative expertise with arms among regular infantry, hadn't realized that difference. So, I am assuming from what you said that the M-16 is an automatic fire weapon... how many rounds are in a single clip, if that's the right word. I'm trying to imagine how often a rifleman would have to change clips in the laying down of a base of fire, over what period, and how many of you would have had to be doing this at once?
> Did those of you who had had a lot of firearms experience from childhood find that you were educating brothers like me about reality once in the field?
> For what reason did you find that you were so often laying down bases of fire, or is this just what an infantry does for attack or defense routinely, even in WW II or Korea or Iraq?
> In laying down such fire did some still use the BAR or equivalent, or larger calibre machine guns, and if so up to what calibres?

[PHO127]

Special forces and special operations teams. Their method of employment is different than standard infantry, along with weapons and methods of engagement. The VN era M16 is a selective fire semi automatic or automatic weapon. later they were made for selective fire semi automatic or Tri-burst (3 rounds on a single pull of the trigger). Maintaining fire rate control was a problem because the M16 on Rock & Roll (Full Auto) would burn thru a 20 round magazine in 3 to 5 seconds, later they went to 30 round magazines. Although clip is a common word, only the M1 rifle is clip fed, the M1 is fed by pushing a pre loaded 8 round clip into a fixed well beneath the bolt. The M14 and M16 are fed by a detachable box magazine. BARs are no longer in use, they have been replaced by the M-60 light machine gun. Again I am speaking of the VN era. A desintgrating belt fed weapon firing a 7.62X51 nato round at about 550 Rounds per second. The oldest weapon we have in the inventory is the Ma Duce, The M2 .50 caliber heavy machine gun. The .50 was not carried to the field by leg infantry but widely (and wildly) used by mechanized infantry and armor. Andy, DMZ-LT and mortardude are the .50 experts. To answer your question about how many did it take to lay a base of fire, it depended on the situation, in an ambush type fire fight whether offensive or defensive it took all and as much ammo as you could fire. normally the first magazine or two was full auto then back down to semi auto.

[SuperScout]

Here are some words of wisdom regarding calibres, calibers, mm or inches:

1. Seriously question yourself before firing any weapon if your body can stand the noise, fun, backblast, muscle requirements, or lack of political correctness in said firing.

2. Seek professional guidance if in doubt, about which end of weapon of questionable calibre, caliber, mm or inch, to firmly grasp.

3. Determine, beyond a reasonable or even unreasonable doubt, from experts in Item #2, which end of said calibre, caliber, mm or inch to be opposite of.

4. Shoot low, using your choice of calibre, caliber, mm, or inches, as the bastards might be riding Shetlands.

[BLUEHAWK]

Scout -
THAT much I did somehow come to intuit prior to this line of questioning, but it's still very humorous of you to offer it the way you did.

Pho -
> My naive assumption is that special ops or forces are basically similar in function, and are much smaller operational units than, say, a company of infantry. I am guessing special forces are in the range of squad or platoon size generally, and in the case of scout (Emperor and otherwise ;-)/snipers, then are individuals or very small teams?
> Was I mistaken, or did I rightly see that some units DID have .50 machine gunners hand-carrying the weapon in 2-man teams during WW II combat at times?
> Is there a difference between a scout and a sniper?

[PHO127]

I want you to go to the library and get a book " Vietnam Order of Battle" by Shelby L. Stanton. Will answer 90% of your questions. If you read it all you will know more than most of the persons that were there.

[BLUEHAWK]

Maestro Pho -
Thou hast enlightened grasshopper in a language he understands, and he will do exactly as you recommended, forthwith.

Over and out...

[SuperScout]

That title kinda has a nice ring to it, doncha agree? In addition to the reams of knowledge you have imparted to the Grasshopper, you might also teach him a bit about proper RTO procedure. "Over and Out..."? That's the proverbial sound of fingernails down the blackboard.

[BLUEHAWK]

Emperor -
Since thou possesseth the wisdom, why did thee not tell grasshopper himself?

And, since thou hast mentioned it, wherefore cometh the proverbial sound of fingernails as was forthed in serf's errant declaration?

[PHO127]

When one has their wits about them and not under the duress of combat there is a defined set of rules by which radio transmissions are supposed to progress. Over and Out is the classic Ronald Regan war movie method of ending a transmission.

Over is used by itself as is also Out. not in combination with each other. Over means you have ended your portion of the conversation and expect a reply from whomever you are talking to. Out means that you have ended your portion of the conversation and have gone back to whatever you were doing prior to being rudly interupted. :D

HOWEVER, transgretions do occur in radio procedure when under the duress of combat. One of our more popular members here was known as "The Screamer" due to the excited nature of his voice under fire. I managed to get chewed out royally by the Commanding General of the 25th Division for leaving my radio mike on in a chopper while directing artillery fire from two different artillery batteries, a forward Air controller bringing in 2 F4 Fantoms, 2 Cobra Gunships, talking to the helicopter pilots to coordinate an artillery prep on a hot LZ while bringing in a platoon on slicks to reinforce the troops already in contact with the enemy and engaging the enemy with my CAR 16 and several expletives, rude comments, discussions of their parentage and expected lifespan. All of which were recorded by an unknown private in some operations center who wanted to let mom and dad back home listen to what a real combat action sounded like. It seems that somehow the recording (or a copy) made it to the brigade briefing and subsequently to the Division briefing. My presence was requested in front of MG Bautz who managed to start at my left boot heel, work all the way up to the back of my head, zig zag across by back several time, cut several circles around my ass and eventually stop at my right boot heel in discussing my obvious lack of radio dicipline and training in radio procedure, and did I know what would happen if Walter Cronkite had got ahold of the tape. I stayed very aware of radio procedure from then on. (with a few minor infractions such as threating to kill a major by shoving a grenade down his throat)

[SuperScout]

Verily, it is written, sometimes in the clouds, sometimes in gazing upon the lent in grasshopper's navel: sharing wisdom from varietal sources of inspiration can frequently impart quantum leaps of learning. Good Maestro PHO has spoken well.

Feline fingernail sounds emanating from the celestial blackboard is a Zen thing. Keep gazing upon said blackboard.

Maestro PHO: your delightful story about questionable RTO procedures brought back many good memories! I can only imagine the gasps of horror from the REMF's at division hq, hearing your rather impassioned requests for fire, reinforcing troops, and a few other combat multipliers. Personally, I was in frequent "discussions" with the ASA pukes about what I could and couldn't say out in the jungle on the radio.

[BLUEHAWK]

Hey Scout-
You musta been an officer. Maestro Pho did your work for ya Emperor! But it got done. Thanks to us all...and him especially.
I have another friend, if I may so designate, this one in personal form, who behaves as you do with my questions. Of course, he was and shall ever be, a Marine, and a captain (ret.).
I must say, however, when I saw TV images of our Marines being landed in Kuwait in a sandstorm absent any shelters some months ago... I complained vociferously that this was NOT a good beginning for the men. I repeated this complaint a number of times to the captain. Whereupon he quietly unholstered his cell phone and made a direct call to the Marine Commandant, relaying my displeasure with logistical malfeasance, asking that the matter be dealt with pronto. It was.

Pho -
- Thusfar I am able to obtain the VIETNAM ORDER OF BATTLE only on DVD, which exceeds my serfly mental capacity at the moment. However, as you see I am learning, many things. A way will be found.
- Neither of you has as yet said exactly what the letters RTO stand for. I guess Radio Transmission, but then what?
- That mom and dad back home who heard your open mike probably did a lot more to convey the meaning of battle than much else that could have been done. Your commander should have given you another medal, or perhaps another stripe.
- Ronald Reagan was it? Now you know how truly antique I am, and from where I have gotten what little I knew up to now.

You guys are great, and grasshopper would make a bothersome but VERY valuable member on any patrol.

[PHO127]

A person that operates a radio or telephone I.E. Radio/Telephone Operator. I was a captain at the time and they did give me a medal, a small piece of shrapnel from hits on the chopper or bullet cut the left side of my face along the cheek. PH #3 and Air Medal with V.

[BLUEHAWK]

Pho -
No wonder the mike was left open...

If I may say so, Welcome home, Sir.

[phuloi]

"must say, however, when I saw TV images of our Marines being landed in Kuwait in a sandstorm absent any shelters some months ago... I complained vociferously that this was NOT a good beginning for the men. I repeated this complaint a number of times to the captain. Whereupon he quietly unholstered his cell phone and made a direct call to the Marine Commandant, relaying my displeasure with logistical malfeasance, asking that the matter be dealt with pronto. It was."
Forgive me for being so blunt here,Hawk.You are full of shit!

[BLUEHAWK]

Griz,

I suppose I am full of it, like most of us... it was a joke Griz, between myself and Scout. But the capn' DID fake a phone call to the Commandant, just to shut me up. It worked.

Hafta say though, I did not see any more images of Marines without shelter halves, on TV, after that.

[revwardoc]

[QUOTE]Originally posted by BLUEHAWK Dan -
> If there is just so much room in a cartridge, then in what manner can one add too much of something, and what is that something that one adds which would knock you on your butt and lay weeds down ahead of the shot?


You'd have to ask another member that question. Personally, the only loading I've ever done is the paper cartridges for my musket and there is an obvious difference there regarding powder quantitiy and quality. But that's a whole other ball of wax as opposed to contemporary ordinance.

[BLUEHAWK]

Thanks Dan - I'm not an especially slow learner, but it can get tough to ask the right questions at times...

[Gunner Carvo]

When it comes to big guns, the bore is the common name: The 5", The 16s. The caliber on these guns is measure not only by the bore of the rifle but also the length. To find the length of a 5" gun multiply by the caliber. 5" X 62 Caliber = 310 inches in length.