U.S. Caliber .30 Cartridges M1906, M1 and M2


#1

In 1906 the U.S. adopted a CN jacketed flat based 150 grain pointed bullet for its Cal. .30 service cartridge, giving birth to the Cal. .30 Model 1906. World War I demonstrated the need for a cartridge with a heavier bullet and longer range for machine gun use, but one that could still be used in the M1903 Springfield rifle. After several years of testing, a new 173 grain GM jacketed boat tailed bullet was finally perfected and in 1926 the Cal. .30 M1 cartridge was adopted.

At this time there were still over two billion of the war time M1906 cartridges on hand. The policy was to use the oldest ammunition first, reserving the new M1 for possible war use. Service, Militia, and Civilian shooters anxiously awaited the day when they would be issued the M1 for use. That day finally arrived in the mid 1930s but with it came some un-welcomed trouble. Not only did the new ammunition kick more, it shot beyond the safety areas of many of the existing rifle ranges.

The first could have been resolved with a simple order - “Complaining about recoil is prohibited”. But the safety issue could not be ignored. The National Guard asked the Ordnance Department to manufacture some reduced power ammunition, more like the original M1906, that could be used on the ranges. The new cartridge was very similar to the M1906, except it had a stannic stained GM jacketed 150 grain bullet so it could be distinguished from the M1. Nine lots were manufactured in 1937 and 12 lots in early 1938. Cartons of the new ammunition were labeled as Caliber .30 M1906. In late 1938 the M1906 designation was dropped and the cartridge was standardized as the Cal. .30 M2.

The M2 continued to be loaded with the stannic stained bullet until the last of the M1 was manufactured in 1941. At that time the stannic stain was discontinued and the well known and recognized GM jacketed M2 bullet became standard.


#2

Thanks a lot for the pictorial comparison. First time I see how the stannic version of the M1 looks like.

Was the M1 rifle in your view an additional reason to drop the M1 cartridge? One would assume it was not only hard on the shooter but also on the mechanism of the rifle.


#3

JPeelen, The M-1 rifle was designed during the M-1 172 grn bullet era so the heavier bullet did not as an old story that never dies claims “would not handle the heavier bullet without damage”. Am guessing after the gas trap M-1 (the first incarnation of the M-1) was abandoned the gas port size in the barrel was adjusted to handle both bullets. As an old competition shooted saw some heavy handloads shot in the M-1 and never saw any more damage than a few bent operating rods.
Gourd


#4

I have seen M1 National Match rifles that have seen heavy-duty match use (read that “lots of rounds down range”) with no damage what-so-ever, and all of the shooting with bullets from 168 to 172 grain. Rifles with bent op rods are normally ones that have been shot with handloads using incorrect powders that have to high a port presssure - that is, the chamber pressure is not too high, but rather the pressure still being generated at the gas port towards the front of the rifle’s barrel. This often goes hand in hand with “rip-through” of the cartridge-case rims by the extractor, as the op rod, and therefore the bolt, are cycling to fast.


#5

Then of course there was the WWII .30 M2 (alternative) ball round with a 150 grain gilding metal coated steel jacketed bullet to conserve copper. I have read that there were more of them made than the standard M2 ball. The M1 Garand damage referred to WAS a bent oprod, which is fairly serious. The Garand was sensitive to increased port pressure, and for that reason loads using heavy bullets and slower-burning powders are to be avoided in it. Propellants in the IMR 3031-IMR 4895 range are best.


#6

Ray,
I hope this doesn’t sound like I am trying to be smart or something like that. But if I understand this correctly, the US changed from the 150grain bullet to the heavier 173grain M1 bullet because of poor machine gun preformance. Then in the 1930s for several reason one of which was range safety the National Guard requested a special run of lighter 150grain bullets for range use. Later this 150 grain bullet became known as the M2 bullet. Then this lighter M2 bullet ends up replacing the heavier M1 bullet as standard issue. My questions would be what ever happened to the machine gun problem? Did range safety and heavy recoil trump better machine gun preformance?
Thanks
Zac


#7

I can think of several reasons for the Army’s going back to the 150 grain round, but I don’t know the actual reasons. As I have understood, the heavier M1 bullet was adopted after WWI, probably because it had a higher BC and increased the extreme range of effectiveness of machine guns. During WWI, this would have been important, as the MG played a role in trench warfare by being an area denial weapon. Just set up some MGs at the elevation for maximum range, point them in the general direction of the enemy, and fire away for hours to keep the Hun from advancing while your own troops maneuver. I imagine this “fighting the last war” mentality prevailed for quite some time after the Armistice. But when it became apparent that it was likely that the next war would not be a repeat of the last one, and would be much more a war of mobility, then the importance of having greater MG range capability was greatly diminished. Second is the problem of the range surface danger zone. The increased range of the M1 in any weapon chambered for it, rifle or MG, would be a major concern for ranges located in populated areas. That would probably be more the case for National Guard ranges than the regular army, but there could be a problem there also. Another factor would be material cost savings. A 150 grain bullet is about 13% less weight than a 172 grain bullet. That decrease in production cost and lowered consumption of scarce raw material resources through the adoption of a lighter bullet, in addition to reduced shipping costs, would be very significant during a war involving the production of multiple billions of rounds of .30 ammunition. And at the distances at which rifles and machine guns would be employed in combat during a mobile war, there would be no tactical advantage to the greater long-range capabilities of the M1 round over the M2. The only exception would be long-range sniping, and I don’t think that was employed much until Vietnam. I doubt reducing recoil was much of a factor but maybe it was.


#8

Cartguy, the machine gun problem simply turned out to not exist.

Cartridges like the U.S. M1, the German sS, the French 1933D, the Soviet D, the Polish D, the British Mk8z and the 8 mm machine gun cartridges of Norway, Sweden and Italy were created with the extremely long range fire in mind, that ensued during the static trench warfare of WW1.
To effectively use machine guns at very long range you need a lot of time and extremely well trained, specialized crews.
In WW2, apart from very isolated events, there was mostly a rather mobile type of warfare. Also, mortars turned out to be much more effective for the purpose.
Therefore, WW1-like longe range machine gun fire practcally did no longer exist in WW2. For directly aimed fire at distances up about one mile, the M2 type cartridges are good enough.