“...then-Army Chief-of-Staff Douglas MacArthur rejected it because he wanted to use up all the mountains of .30-06 M2 Ball left over from the last war...” [The Pack Knight, post 57]
There was no Cal 30 Ball M2 left over from World War One. The round wasn’t developed until the 1930s - after John Garand’s rifle had been developed.
The original cal 30 M1906 round was used throughout WW1.
Cal 30 Ball M1 was developed in the 1920s: loaded with a 172gr boat-tail bullet, optimized for performance at extreme range fired from machine guns (think M1917 water-cooled gun). But it was found that it could not be fired from the Garand design, at the muzzle velocities required, without shortening parts service life unacceptably. Army Ordnance moved on to develop Cal 30 Ball M2, firing a flat base 152gr bullet to a muzzle velocity of 2750 ft/sec.
It was foreseen that newer weapons coming into the inventory, and newer operating concepts for mobile operations, would reduce requirements for long-range fire from tripod-mounted machine guns. At the same time, it was decided that anticipated max effective range of individual rifle fire was no more than 600 yds; inside that, performance difference between Ball M1 and Ball M2 was negligible.
Then-Chief of Staff MacArthur based his decision to retain 30-06 on staff advice that chambering a new standard issue rifle in any caliber other than 30-06 (in some variant) would not allow for proper utilization of other small arms like BAR M1918A2, belt-fed machine guns, and M1903 rifle variants (which remained in production until 1944 as substitute standard). At the time, it was considered very important for small arms to chamber the same cartridge, as completely as possible.
This has been covered in detail, in _The Book of the Garand_ by Maj Gen Julian S Hatcher.
“...Why did the Army choose the Trap Door Springfield in 1873 instead of other, more reliable rifles, or even, God forbid, a repeater? Because they could convert existing 1863 Springfield Muskets to Trap Doors for five bucks a pop rather than buy whole new rifles,...they really were junk compared to what was available...” [The Pack Knight, post 57]
None of these claims are supported by the facts.
The federal government made rifles then, it didn’t buy them unless no other options were available. Springfield Armory, and Harpers Ferry before 1861, were internationally recognized leaders in manufacturing.
Numerous conversions were attempted, of muzzle-loading rifle-muskets from the 1855-1864 timeframe, made largely for the American Civil War. The goal was to save funds by using up obsolete arms and materiel already owned by the War Dept. The “Trap Door” design invented by Erskine S Allin, Master Armorer at Springfield Armory ,was chosen as the best. Obsolete muzzle-loaders and stocks of replacement parts were used in Rifles Model 1865, 1866, 1868, 1870, and closely related Cadet models. Calibers were 58 rimfire and 50 centerfire.
The Rifles Model 1873, 1875, 1877, 1880, 1884, 1888 (and closely related Cadet and Long Range/Marksman models) all were made with cal 45 bores but a few chambered differing cartridge case lengths. Manufacturing methods and materials had changed drastically, and there was no parts commonality between the 45 cal rifles and earlier rifles.
The 45-70 Trap Door is often derided by latter-day gun enthusiasts as weak and marginally functional, but such was not the case back then. It was as strong and as functionally reliable as the best single-shots of the day. Joseph G Bilby, a leading expert on ACW small arms and their successors, has examined and fired Trap Doors and other contemporary single-shots, and has concluded that Trap Door was at least the equal of Remington’s Rolling Block, the principal rifle it’s compared with. Quality of materials, manufacturing, and level of craftsmanship evinced in the Springfield-made Trap Doors is as high as any standard-style rifle of the period.
Stuck cases and case-head separations bedeviled all small arms of that time, not strictly Trap Door Springfields to any excessive degree. It was a limitation on ammunition manufacture, not deficiencies in rifle design. Difficulties were not overcome until advances in brass metallurgy and deep-draw case forming were made by the British, in the late 1870s.
The argument about repeater vs single-shot raged for years, but repeaters were then quite unproven and few were reliable. The most popular ones like Winchester’s 1866 and 1873 fired small, weak cartridges but were still quite heavy.
Army Ordnance did acquire a number of repeaters for service tests, but rejected them on grounds of poor reliability and suitability. Not only was it feared that soldiers would fire off all their ammunition too early, it was judged they would balk at carrying the weighty repeaters. Anyone who has hefted a Hotchkiss, a Remington-Lee, a Winchester 1886, a Marlin 1881, or a Chaffee-Reese fully loaded with 45-70 rounds can attest how heavy they are.