What is the most Historically Significant Cartridge?

The 45 Colt . . . now there's one that may not be THE most historically significant cartridge, but it's one that has a truly fascinating history in and of itself. And, as Sandwarrior correctly points out, a great deal of its historic reputation more properly belongs to the 45 S&W cartridge, or one of the derivatives such as the nearly identical 45 Schofield or the 45 Colt Government (AKA 45 Short Colt). Add to that the M1909 version of the 45 Colt, and yeah, there's a wild history there.
 
How about the round that inspired the 06 the 8mm Mauser. Before the 06 we had the 30-03which did poorly against the 8mm.

The 30-03 didn't do poorly against the 8mm Mauser. It's just that the U.S. adopted the 30-03 intending it to launch a 220 gr. bullet. In 1905 the Germans switched bullets going from a 225 gr. (14.6 gram) down to a pointed 155 gr. The U.S. followed suit and changed from the 220 gr. bullet in the .30-03 to 150 gr. In doing so it was necessary to shorten the neck to accommodate the spitzer bullet.

In my mind, they are pretty much one and the same. While different physically, the change came from an adaptation that had to be made for it to function in the rifle. It didn't change the load capacity or general shape, thus, overall capability of the round didn't change.
 
Not sure if its already been said; and I havent finished reading past Tiro`s and sandwarriors comments but will come back to them, I am inclined to think there is more than some merit in an advisory board NOT being able to come up with its own cartridge without anyone in the industry testing. BTW sandwarrior, is there any difference in case body diameter between the x55 Swede and x57 case?

Anyway, one thing I wanted to bring up, everyone keeps saying the .30-06 is the parent cartridge of the .308, but Ive always been under the impression the .300 Savage is the parent?
 
Anyway, one thing I wanted to bring up, everyone keeps saying the .30-06 is the parent cartridge of the .308, but Ive always been under the impression the .300 Savage is the parent?

Yes, the .300 Savage was the "parent case" who's parent case was the .250-3000 Savage and guess which case was that round's parent case. Yup! The 30-06.

Maybe not the .308's parent case directly but at least the "great-grandfather" :)
 
9x19 Parabellum/Luger?

Over 110 years behind, and "According to the 2006 edition of*Cartridges of the World, the 9×19mm Parabellum is "the world's most popular and widely used military handgun cartridge".
 
I guess from a modern military perspective the advent of accurized .50 bmg's, 338 Lapua and the 300wm is the most significant that have allowed our Mil snipers incredible stand-off ranges which has probably saved more lives vs. any time in historical warfare.
 
I guess from a modern military perspective the advent of accurized .50 bmg's, 338 Lapua and the 300wm is the most significant that have allowed our Mil snipers incredible stand-off ranges which has probably saved more lives vs. any time in historical warfare.

That's a stretch to say the least. The two above may have extended the range a bit, but for covering troops that's the exception. Average Sniper shots are still well under 500 yards.

Hard to convince the Marines on Okinawa those old guns didn't work, after Private David W. Cass Jr. took out a Japanese Machine Gun crew at 1200 yards with one of those old Springfield Sniper Rifles. I believe that was after the Marines replaced the M1941s with the Army's M1903A4s.
 
...Hard to convince the Marines on Okinawa those old guns didn't work, after Private David W. Cass Jr. took out a Japanese Machine Gun crew at 1200 yards with one of those old Springfield Sniper Rifles. I believe that was after the Marines replaced the M1941s with the Army's M1903A4s.

...I believe that was before the press could teach them that a .338 is an absolute must_
 
My thread on cartridge stagnation got me to thinking about the most historically significant cartridge in terms of its influence on future firearm/cartridge development and/or world events. Rather than alter my previous thread, I thought I'd start a new discussion. So here we go: What is the most historically significant small arms cartridge ever developed, and why?

HRF

.30-06 and the 1903 Springfield. Here's why, at a place called, Belleau Wood;

Marines of WW1
 
I'd have to go with flaming balls of oil and tar flung from a trebuchete

Not sure that falls under "cartridge", but if we're gonna go there, I'd say... the development of language. Allowed us to pass along knowledge, advance agriculture, settlements, specialization, technology, eventually firearms. Kind of the "parent case" of all of 'em.
 
Unbelievable! Whilst I would agree with the .22 comments - only one other person has mentioned the venerable .303! I've often been told that this round has accounted for more game, enemies of empire and other targets around the world than any other cartridge..... ducking down for tirade of abuse :)
 
Lefaucheux pin fire gets my vote being it is the first self contained metallic cartridge. It completely changed warfare and firearms in a matter of a few decades. Even though it was a short lived design, without it, firearms would not be what they are today.
 
That's a stretch to say the least. The two above may have extended the range a bit, but for covering troops that's the exception. Average Sniper shots are still well under 500 yards.

Hard to convince the Marines on Okinawa those old guns didn't work, after Private David W. Cass Jr. took out a Japanese Machine Gun crew at 1200 yards with one of those old Springfield Sniper Rifles. I believe that was after the Marines replaced the M1941s with the Army's M1903A4s.

Those Vets were all hero's in Okinawa and never would take away from that.

Guess my point is with today's modern long range cartridges we see hits with much more regularity and yes I believe we've saved more lives than we've ever had because of our increased stand off ranges.
 
My opinion is the .625 ball and leather patch used by the British infantry. It showed the whole of Eurasia that the rifle was an absolutely deadly killing machine compared to the musket. After that I would say the Minie ball, followed by the 8mm Lebel. Most recently I think the 7.92x33mm has been the most influential cartridge, as almost every assault rifle to date uses a cartridge based off of its principals of design and use.