A few years after the end of WWII, Johnson played with and developed a cartridge that is comparable with most “Assault Rifle” cartridges of today, the 5.7mm Johnson. It is a necked down 30 caliber M1 Carbine case, with a 40-grain bullet traveling between 2700 and 3000 feet per second (fps). Its platform was an M1 Carbine with a new barrel in .22 caliber with some minor modifications to the receivers feed ramp. As the M1 Carbine used a thirty (30) round magazine, and with the appropriate parts could be converted to select fire (semi-auto and full auto) using a selector switch, Johnson had really developed a modern small caliber Assault Rifle, years ahead of it’s time.
Back in the early 1960’s, when Johnson developed his 5.7 cartridge, small caliber weapons were frowned upon by “experts” that were convinced that such a small caliber cartridge was inadequate for military purposes. How strange that only a few years later our military decided that the M14 rifles that the U.S. had adopted were too big, clumsy, and over powered for the jungles of Vietnam and replaced it with the M16 rifle, at the cost of millions of wasted tax dollars and the lives of not a few soldiers during the “teething period” of that rifles development. How much money and lives might have been saved if the U.S. had merely taken all the many thousands of M1 Carbines in inventory and storage and had them converted to 5.7 Johnson. I once knew a former Marine who, when he first deployed to Vietnam, was issued an M2 .30 caliber Carbine, for which he was immensely grateful as it was far more controllable than an M14 on automatic fire, was less than half the weight, and he was able to carry a lot of spare magazines with more than double the “combat load” of the M14.
Looking at an M1 Carbine, one sees a light carbine, handy, well balanced, of a good capacity, and “battle tested.” While there has been some ill feelings and bad press on occasion berating the M1 Carbine, I wonder if it is just sour grapes combined with an ammunition problem. During the Korean War, the M1 and M2 Carbines were issued by the thousands. Some felt that it didn’t “work as advertised” in the bitterly cold weather. Stories of multiple hits on Chinese soldiers where the .30 Carbine failed to stop them are easy to find. As the .30 Carbine has as much power as a .357 Magnum at 100 yards, I wonder if anyone actually counted the number of hits, rather than blame the carbine. As the temperature was as cold as a body could ever imagine, I wonder if the powder charge was affected by the cold and failed to do its job.