Why .30 caliber historically for military?

[valnar]

It seems a lot of the old military bolt action "full power" rifles were built on a .30 caliber (or so) bullet. You have .30-06, 7.62x54r, 8x57, 7.5x55, .303, etc. They all have around 2600-2900 ft-lbf energy. I can only imagine the punishment from these calibers can be pretty brutal in warfare after firing 50+ or more rounds in a day.

Admittedly I am not a ballistics, tactical nor hunting expert. However, I've read enough to know that something as little as a .243 can take down a deer handedly and a 6.5x55 160gr is good for almost anything "man sized" or bigger, including Elk.

So that being said, why wasn't something a little tamer chosen for the World's military 100 years ago? Surely all those 18yr old soldiers would have handled a less recoiling rifle easier, with better accuracy and endurance? The range and wind resistance on a quarter-bore or .260 sized bullet is just as good as a .30, with enough power necessary for a 250 pound human.

So why was the .30 caliber at ~2700 ft/s chosen as the "standard" back then, and somehow universally by many different countries?

 

[Arkansas Paul]

However, I've read enough to know that something as little as a .243 can take down a deer handedly and a 6.5x55 160gr is good for almost anything "man sized" or bigger, including Elk.

Deer and elk don't wear body armour or hide behind vehicles and walls. People do.

 

[valnar]

Deer and elk don't wear body armour or hide behind vehicles and walls. People do.

While I don't doubt that is true, was that the reason around 1910?

 

[silicosys4]

There are plenty of "modern" military cartridges chambered in non-.30 caliber rifles. 7mm mauser...8mm mauser... 7.5mm is a french military round....and 6.5x55 that you mentioned is actually a military round as seen in the k31's. In fact, many of the "metric" modern hunting cartridges in Europe started life as military chamberings...Could it be coincidence that the .30 diameter bullets offer the best downrange performance, velocity, and efficiency, as well as versatility in loading.....for what the U.S. army wanted to do? Or does the U.S. just use the inch system and .30 was a nice round number, vs. europes metric system...both like nice round numbers. I would say that the .30 was just the best diameter for the job in retaining energy, in velocity, for the new smokeless powders just being invented....Smokeless powder changed the game from huge, large caliber bullets lumbering along to small fast light bullets at high velocity. If you have to use blackpowder, you are limited severely in velocity....so you pretty much have to use huge bullets to get any long range performance. Smokeless powder gives much higher velocity, smaller bullets at higher velocities have a much better trajectory, but at some point you give up terminal performance and penetration...... I would assume .30 is just the diameter that "balanced" all these factors out in the tests by the U.S. Army. Now that we know more about ballistics and effective terminal performance, there hasn't been a .30 military cartridge developed in how long?

 

[rule303]

The calibers you mention were considered small bore, and lighter recoiling for that time period (late 1800's/early 1900's).

 

[Vern Humphrey]

The most common military calibers in the late 1900s ran the gamut from 7mm (.28 caliber) to 8mm (.31-32 caliber). Thirty caliber falls right in the middle of that range.

 

[tyeo098]

Calibers are a trend of shrinking.
1700's was the 50 or 60 cal musket ball.
1800's was the wise of the 45/70 Gov't
1900's we see the 30 cals you listed, -06,x54R,x39,303 etc.
Late 1900's we see 22 cals 5.45x39, 5x56.45
Now we are seeing 17cal PDW's like the PS90 and stuff.

How long is it before we are shooting needles at eachother D:

 

[valnar]

tyeo098, you made my point.

If any of those calibers can effectively kill a human (admittedly at different velocities), do we know WHY the .28-.31 caliber was chosen by so many different countries independently during the same time period? I find that the most fascinating.

I'm okay with discussion and speculation, but I'd love to know the real reason.

 

[tnelson31]

Velocity?

 

[dprice3844444]

penetration through brick walls

 

[rcmodel]

The 8×50mmR French (8 mm Lebel) rifle cartridge was the first smokeless powder military cartridge to be made and adopted by any country in 1886.
It was followed in 1898 by the first spitzer boat-tail bullet used in it.

Between the two, it was a revelation to other military powers as to it's extreme long range performance, especially out of machineguns.

After that, every other country was chasing after the 8mm Lebel, trying to extend the range of the opposing machinegun battery's to at least match it.

The U.S. had already tried the 6mm Lee Navy in 1895, and it was a dismal failure due to severe bore erosion in the small bore with the early hot burning smokeless powders of the time.
They soon went to a .30 caliber in the 30-40 Krag, and got much improved barrel life among other things.

As it turned out, .30 / 8mm and spitzer boat-tails became the norm, following the lead of the French 8mm.

Either that, or somebody got a heck of a good deal on .300" deep hole drill bits at Harbor Freight??

rc

 

[Jim Watson]

And .30 is an even number in inches, too.

In the late 19th century, the armies were still thinking in terms of massed volley fire at long range. In WW I the rifle caliber machine gun became standard equipment. Both of these jobs called for more power than was strictly necessary for an individual infantry weapon, so the issue was made for the longest range application. The .30cal - 8mm range Just Worked for that.

By WWII there were two trends.
Early on, the smallbore combatants, Japan and Italy, decided their nice mild 6.5s were not powerful enough and went through a rearmament program in 7.7 and 7.35mm, respectively. Probably not a good idea after the war was already going on. Japan followed through but had to supply two sets of guns and ammo ever after. Italy backed down and went back to 6.5, some 7.35s converted, some warehoused, some found as far away as Finland.

Later, artillery, machine guns, tanks and aircraft were handling most of the long range work and thought could be given to lighter caliber infantry weapons with less recoil and more ammunition in a basic loadout. The Germans got some 7.9x33s going, the Soviets were on the way to 7.62x39 but did not make the actual changeover until after the war. We used a lot of M1 Carbines as primary weapons instead of their original intended issue in lieu of pistols.

True smallbores did not become truly practical until propellants and barrel steel were good enough for high velocity to make up for low mass.

Mauser had advertised that they were prepared to supply rifles in calibers as small as 5mm in the late 1890s but I think the Powers were smart not to fall for it. The US 6mm Lee Navy of the day was no great success.

 

[Owen Sparks]

.30 was the traditional caliber used by the US (and still is for heavy machineguns and some rifles) The British .303 and Comunist block 7.62 use a slightly larger .311 diamiter bullet than the US .30 which is actually .308.
European powers chose calibers in metric diamiters, 6.5, 7MM, 8MM etc.

 

[lemaymiami]

Valnar, I can't say why the caliber 30 seemed to be the round of choice but I do remember a bit about the military philosophy (at least what I've read). In that era soldiers were expected to engage at longer distances (particularly in defensive battles). For that time (in the early smokeless era) I suspect that 30 caliber gave them the performance they wanted. One other item to remember.... the battle rifles back then weren't exactly lightweights... Lots of difference between 30.06 in a lightweight modern rifle and something that weighed as much as five or six pounds more as far as recoil goes... If I"m off base here, hope someone will correct me...

 

[WardenWolf]

.30 caliber was just determined to be more or less ideal in regards to range, recoil, lethality, and gun weight with the early smokeless powders and the metallurgy of the time. Additionally, militaries of the time were looking into more longterm solutions, and there was a real competition between the various nations to build the best rifle.

 

[rcmodel]

I think off base a just a little.

A typical 98 Mauser or 03 Springfield weighed right at 8 3/4 - 9 pounds.

Or about the same as a modern standard weight 30-06 sporting rifle with a scope on it.

In no case were any of them 5 - 6 pounds heavier.

rc

 

[Coop45]

The 6mm Lee was also deemed to be ineffective in stopping Moros at close range. Marines in the Philippines were the first to receive the .30cal Krag rifle when it became available. During it's short service life the Lee served in both Cuba and China.

 

[Skribs]

OP, you left out 7.62 NATO and 7.62x39!

Now we are seeing 17cal PDW's like the PS90 and stuff.

Unless you're talking about a different weapon than what I'm thinking of, the P90 uses a 5.7x28mm cartridge, which is actually slightly wider than the .223 or 5.56 cartridge. The gun that actually is named PDW uses a 6.5mm cartridge.

I don't personally envision us going much smaller. In fact, the push by a lot of people seems to go back up to that 6.5-8mm range with the AR cartridges like 6.8 SPC and 300 Blackout coming out. The smallest one I've seen tried in a military setting is 4.6x30, but it was determined 5.7 was better.

 

[valnar]

All cool info. Thanks.

 

[Canuck-IL]

...and 6.5x55 that you mentioned is actually a military round as seen in the k31's... (Silicosys4)

K31s would be 7.5 * 55 Swiss ... 6.5 is used in Swede Mauser variants.

/Bryan

 

[Sergei Mosin]

One factor not mentioned - horses. Whether used in cavalry, mounted infantry, or logistics units, killing the enemy's horses required a large, heavy bullet.

 

[shadow9]

Two theories:

Sub .30-cal is typically abrasive to barrels, while anything larger than .30 is abrasive to shooters. Also, heavier bullets have more of an arc.
However, in another post (I believe somewhere on Sniper'sHide), two LR (600-1000yd) competitive shooters were discussing ballistic preferences, and the conclusion was that while 6.5 and 7mm dominated aerodynamic-to-weight ratio, the .30 cal was disturbingly CONSISTENT. Small fluctuations (powder charge, wind, etc) would not alter the .30's course as much as the smallbores, and in war, you really REALLY want consistent.

Another thought - the .30-03 and .30-06 JUST came out in that time period, and honestly, the .30 range calibers didn't really have many problems in warfare. End WWI, and you've only got a short break before WWII, and economic depression in many countries. The .30 did just fine in WWI, and with the short notice to WWII and our depression (read: less $$ for development), it just didn't make sense to try to develop an all-new caliber for our weapons, or any of the other countries suffering after WWI. So, we just kept using .30 cal.

All just theory, since those folks that were around between 1915 and 1955 are either deceased now, or probably not active members of this here forum..

 

[Sam1911]

It seems a lot of the old military bolt action "full power" rifles were built on a .30 caliber (or so) bullet. You have .30-06, 7.62x54r, 8x57, 7.5x55, .303, etc. They all have around 2600-2900 ft-lbf energy. I can only imagine the punishment from these calibers can be pretty brutal in warfare after firing 50+ or more rounds in a day.

One thing to really stop and consider is what the trend was in infantry arms prior to the end of the 19th century. A .30-40 Krag was a teensy little lightweight compared to what had come before. .45-70 Gov't, various large-bore cartridges in other countries, and very shortly before that .58-.75 caliber muzzle-loading arms of many types.

Little and fast was a brand new thing. There were a variety of smaller bores tried (6mm Lee-Navy, for example) but when you consider how conservative militaries generally are, perhaps there was only so far they could go!

Now, when you've expected your troops to fire 500 grain .577 minne balls all day, or 405 gr. .45 cal bullets, firing little 150-200 gr. .308" bullets is child's play.

Admittedly I am not a ballistics, tactical nor hunting expert. However, I've read enough to know that something as little as a .243 can take down a deer handedly and a 6.5x55 160gr is good for almost anything "man sized" or bigger, including Elk.

Sure! And our troops prove every single day that a 55-69 gr. .224 will do the job very well, too! But look how long it took to move to acceptance of that.

So why was the .30 caliber at ~2700 ft/s chosen as the "standard" back then, and somehow universally by many different countries?

Well, there is a lot of duplication of efforts by developers in different countries, a lot of copy-catting, a lot of "prevailing wisdom." And then there are efforts at standardization among allies, which compete with efforts to buck the trend (like the .276 Pedersen round which would probably have been stellar!).

 

[Derek Zeanah]

I'm no expert, but I'd say that we've seen a long-term (as in multi-century) drive toward smaller calibers as technology improved. .70 cal, to .50 cal, then .45, then .30, then .22...

The number of 30's you're seeing may just be a function of metallurgy and cartridge technology mixed with typical military conservatism, plus logistics concerns.

 

[Reloadron]

Something of useless interest is as far back as 1923 the US was considering a .276 round known as the 276 Pederson:

Developed in 1923 in the United States, it was intended to replace the .30-06 Springfield in new semi-automatic rifles and machine guns. When first recommended for adoption, M1 Garand rifles were chambered for the .276 Pedersen, which held ten rounds in its unique en-bloc clips. The .276 Pedersen was a shorter, lighter and lower pressure round than the .30-06, which made the design of an autoloading rifle easier than the long, powerful .30-06. The US Army Chief of Staff Gen. Douglas MacArthur rejected the .276 Pedersen Garand in 1932 after verifying that a .30-06 version was feasible.

The above quote was taken from here where more reading may be found. So actually for what it may or may not be worth the earliest M1 Garands were chambered for the 276 Pederson as a 10 round semi automatic rifle. Had General MacArthur not shot the cartridge down the US would have went from 7.62mm to 7mm much earlier in the game.

For What It's Worth...

Ron