{"id":68849,"date":"2017-01-25T14:22:38","date_gmt":"2017-01-25T19:22:38","guid":{"rendered":"https:\/\/www.gunsamerica.com\/blog\/?p=68849"},"modified":"2017-01-25T14:22:38","modified_gmt":"2023-08-20T16:48:59","slug":"milsurp-full-auto-garand-secret-world-war-ii-era-t20-rifle","status":"publish","type":"post","link":"https:\/\/gunsamerica.com\/digest\/milsurp-full-auto-garand-secret-world-war-ii-era-t20-rifle\/","title":{"rendered":"MilSurp: A Full-Auto Garand? The Secret World War II-Era T20 Rifle."},"content":{"rendered":"
\"MilSurp:<\/a>

John Garand’s first selective-fire prototype, attempting to up the firepower of the classic battle rifle. Image courtesy of Bruce N. Canfield.<\/p><\/div>\n

\"MilSurp:<\/a>

Bruce N. Canfield’s book, “The M1 Garand Rifle,” published by Mowbray Publishers, is the source of the interesting material in this article. To learn more, pick up your own copy of the 872-page tome.<\/p><\/div>\n

To learn more, visit https:\/\/gunandswordcollector.com\/Templates\/book%20pages\/canfield_M1garand.html<\/a>.<\/p>\n

To purchase an M1 Garand on GunsAmerica.com, click this link: https:\/\/www.gunsamerica.com\/Search.aspx?T=m1%20garand<\/a>.<\/p>\n

Editor\u2019s Note:<\/strong>\u00a0This piece is an abridged excerpt from the book <\/em>The M1 Garand Rifle<\/a> by Bruce N. Canfield. If you would like to explore this subject in greater detail, you can obtain a copy of the 872-page book from Mowbray Publishing, 54 East School St., Woonsocket, RI 02895.<\/em><\/p>\n

During World War II, the Ordnance Department granted a number of developmental contracts for various types of weapons. These weapons were given a \u201cT\u201d (Test) prefix and were intended either to modify the existing M1 rifle to increase its utility or were an entirely different type of weapon that might prove to be an improvement over the Garand.<\/p>\n

The Springfield Armory T20 and variants \u2014 a Glimpse at the Future<\/strong><\/h2>\n

Early in World War II, it was seen that an M1 rifle capable of selective-fire (semi-automatic and fully automatic capability) could be a notable improvement over the standard semiautomatic-only rifle with a limited (eight-round) magazine capacity. To this end, there was a great deal of interest in the possibility of developing a selective-fire, detachable-magazine weapon based on the Garand rifle. Firearm designers soon ran into the same problem that had caused much consternation back in the 1920s and early 1930s when John Pedersen and John Garand were working on their semiautomatic rifles. The problem encountered then was the proper cartridge for a semiautomatic rifle. One of the strong arguments in favor of Pedersen\u2019s reduced-caliber .276 cartridge was that the smaller bullet did not generate as much heat when firing semiautomatically as did the larger .30-caliber cartridge. As gun engineers studied the concept of a selective-fire Garand in the early 1940s, the heating problem again arose, but this time it was greatly magnified when full-automatic fire was factored into the equation. Also, the Garand\u2019s limited eight-round magazine capacity hampered effective use of such a weapon when firing in the full-automatic mode.<\/p>\n

\"MilSurp:<\/a>

Shown is the T20 selective-fire rifle, John Garand’s first “T”-variant rifle. Image courtesy of Frank Iannamico.<\/p><\/div>\n

As indicated by a May 1942 Springfield Armory report, John Garand was developing a selective-fire version of his rifle fitted with a BAR barrel and capable of being used with the BAR\u2019s 20-round detachable-box magazine. The above-referenced heating problem was evident in a Springfield Armory report, which stated that, because of the large capacity magazine, \u201c\u2026problems could well arise due to overheating and cook-off.\u201d It was also reported that Mr. Garand discovered that the additional force required to strip cartridges from the extended magazine resulted in increased friction. The project seems to have been put on the back burner for a couple of years due to more pressing matters, as there are only a few sporadic reports on further development of the design later in 1942 and for most of 1943.In early 1944, however, the project was resurrected and became the focus of a great deal of attention by Springfield Armory. As related by R. Blake Stevens in his marvelous book<\/p>\n

In early 1944, however, the project was resurrected and became the focus of a great deal of attention by Springfield Armory. As related by R. Blake Stevens in his marvelous book U.S. Rifle M14 \u2014 From John Garand to the M21<\/em>:<\/p>\n

\"MilSurp:<\/a>

View of T20 rifle fitted M1 bayonet and M81\/82 telescope. The weapon was designed to be compatible with items previously standardized for the M1 rifle. Image courtesy of SANHS\/NPS.<\/p><\/div>\n

\u201cReports on the initial trials of the 20-shot M1 model, already made up as mentioned\u2026by John Garand in response to the Ordnance Department\u2019s 1942 request, had noted that the rifle was particularly sensitive to feeding while on automatic fire. With the heavy column of cartridges in the 20-round BAR magazine, the relatively light M1 bolt did not stay open long enough for the cartridges to rise sufficiently to present the base of the leading round for feeding, and as a result the rifle jammed. John Garand reported that either the magazine and its spring had to be redesigned to make its action stiffer, thus losing the desirable feature of interchangeability with the BAR and increasing breech mechanism friction even more, or the rear portion of the M1\u2019s receiver had to be lengthened slightly. This would allow the bolt to recoil farther, thus giving the stack of cartridges in the magazine more time to rise. (In what seemed like the \u2018good old days,\u2019 a jamming problem attributable to the same source had been encountered in a rifle design by a Lt. Hawkins back in 1910. The problem was overcome by simply shortening the cartridges!). No such option was open to John Garand in 1944.\u201d<\/p>\n

\"MilSurp:<\/a>

Shown is serial number 8 T20 rifle. The rear sight is believed to be an experimental Bennel model. Image courtesy of Frank Iannamico.<\/p><\/div>\n

The Ordnance Department\u2019s relatively new policy of utilizing Springfield Armory for extensive research and development work, in addition to its traditional role as a manufacturer, was one of those things that sounded good in theory but did not always work out so well in practice. Additionally, the requirements of the using services and the realities of small arms design and production could often conflict. The development of a selective-fire Garand vividly highlighted both conflicts.<\/p>\n

The T20<\/strong><\/h2>\n

Despite the above challenges, the Ordnance Department\u2019s Technical Committee recommended that Springfield Armory proceed posthaste with the development of a selective-fire version of the M1 rifle fitted with a detachable-box magazine. The weapon was designated as the T20. One of the first issues to tackle was the feeding problems encountered with the 20-round BAR magazine. The difficulty was one of simple physics. A stack of 20 cartridges is heavy and, therefore, rather difficult to lift into the path of the bolt. John Garand championed lengthening the receiver, which was ultimately the option selected.<\/p>\n

\"MilSurp:<\/a>

The T20 had a distinctive muzzle brake design to help control recoil under fire. Image courtesy of Frank Iannamico.<\/p><\/div>\n

A September 1944 Springfield Armory report noted: \u201cInitial trial model of the T20 has been started in this shop. Receiver length will be longer than that of the M1 rifle\u2026 Data are being assembled on time intervals involved in feeding in\u2026selected\u2026slow and fast M1 rifles.\u201d<\/p>\n

Although the Springfield Armory production staff was strongly in favor of keeping the original M1 rifle design as unchanged as possible, each subsequent permutation of the new weapon resulted in the basic M1 action being further altered.<\/p>\n

The initial design was intended to permit semiautomatic fire from a closed bolt (as with the standard M1 rifle) and automatic fire from an open bolt (as with the BAR and most other automatic weapons). However, the Aberdeen testing concluded that, while theoretically desirable, such a mechanism was impractical and this requirement was dropped. It should be noted that one of the few WWII-era selective-fire weapons that successfully employed both closed-bolt (for semiautomatic operation) and open-bolt operation (for fully automatic operation) was the Johnson Light Machine Gun.<\/p>\n

In any event, these issues, plus the necessity to redesign some parts to increase their strength, resulted in the T20 being superseded in January 1945 by the T20E1.<\/p>\n

\"MilSurp:<\/a>

The T20E1 variant of the T20 series incorporated incremental improvements over the T20 rifle. Note the heel of the slightly redesigned receiver. Image courtesy of Frank Iannamico.<\/p><\/div>\n

The T20E1<\/strong><\/h2>\n

The book U.S. Rifle M14 \u2014 From John Garand to the M21<\/em> contains the following summation of the T20E1 tests at Aberdeen Proving Ground:<\/p>\n

\u201cAt the Aberdeen T20 trial, excessive flash, recoil, muzzle blast and climb were reported. Overheating on rapid fire was a problem, and the open-bolt full auto feature did not materially reduce the incidence of cook-off. In addition, the timing of this open-bolt device was found to be in question, as, depending on when the firer released the trigger, the action might come to rest with the bolt open or closed. Nevertheless, a hard-pressed, wartime Aberdeen Proving Ground concluded that the basic principle of operation was satisfactory, admitting that the \u2018noted feed failures were due mainly to battered and deformed BAR magazines.\u2019 They recommend certain specified, relatively minor changes, and the strengthening of various components, saying that these modifications should be undertaken immediately.\u201d<\/p>\n

\"MilSurp:<\/a>

The T20E1 had a new muzzle brake design developed to help control excessive muzzle blast and flash. Image courtesy of Frank Iannamico.<\/p><\/div>\n

After reviewing the results of the recently concluded Aberdeen testing, the Ordnance Technical Committee determined that some of the initial requirements desired for the proposed new weapon such as firing from an open bolt, a folding stock and short barrel (the latter two features for airborne use) were impractical or unnecessary. After evaluating the reports of the testing, John Garand began work on incorporating the various recommended revisions into an improved version of the weapon designated as the T20E1. The new design was evaluated, and the results were sufficiently encouraging to result in ten rifles being fabricated for further testing, including limited troop trials after which another 100 examples were to be manufactured. The Ordnance Department publication Record of Army Ordnance Research and Development, 1946, compiled under the direction of Col. R.R. Studler, contained the following regarding the T20E1 rifle:<\/p>\n

\u201cThe T20E1 Rifle, incorporating the changes desired as a result of testing previous models, fired both automatic and semi-automatic from a closed bolt, omitting the unsatisfactory feature for holding the bolt open on automatic fire and substituting in lieu thereof two heat flow arresting grooves on the barrel before the chamber for chamber cooling. In addition, the receiver was further modified to simplify the operation of locking the receiver and trigger group together as well as to introduce a more secure means of locking the box magazine within the magazine well. At the same time, the receiver was prepared to mount a telescopic sight, night sight, or grenade launcher sight, as might be desired. The recoil check was modified to take a bayonet. However, the T20E1 was still incapable of mounting a grenade launcher or flash hider. A new box magazine to replace the modified BAR magazine was developed to work in conjunction with the new method of locking in the receiver, and thus this magazine provided the only means of holding the bolt to the rear in its retracted position. This magazine was not interchangeable for use in the BAR.<\/p>\n

The T20E1 Rifle mounted an adjustable bipod from the gas cylinder but this bipod was not readily removable.<\/p>\n

During the period of 22 through 26 January 1945, the T20E1 Rifle was tested at the Ordnance Research Center, Aberdeen Proving Ground. This model was complete in all details, and the test results, other than the failures to feed, were exceptional. These failures to feed were caused by the bolt bearing surface in the barrel being soft. The following minor changes and improvements were authorized to be incorporated in the 10 Rifles T20E1 to be fabricated for service test:
\n\u2022\u00a0\u00a0 \u00a0Induction harden the breech end of the barrel.
\n\u2022\u00a0\u00a0 \u00a0Increase length of the bipod to permit greater command height.
\n\u2022\u00a0\u00a0 \u00a0Redesign the gas cylinder and gas cylinder lock screw assembly to permit ready attachment and removal of rifle accessories.
\n\u2022\u00a0\u00a0 \u00a0Improve the handguard to prevent charring.\u201d<\/p>\n

\"MilSurp:<\/a>

The T20E2 took everything that had been learned through the T20E1 model and adapted it to address those concerns. Image courtesy of Frank Iannamico.<\/p><\/div>\n

The T20E2<\/strong><\/h2>\n

After the above improvements were incorporated into the design, the revised T20E1 rifle was tested further by the Infantry Board and the U.S. Marine Corps Equipment Board. These tests resulted in several additional recommended changes, which were significant enough to warrant a re-designation of the weapon to \u201cT20E2.\u201d The Army Ordnance R&D Record for Fiscal Year 1946 contained details of the recommended changes and the order for the new designation:\u201cFurther tests of the T20E1 Rifle by the Infantry Board and the Marine Corps Equipment board resulted in the incorporation in the T20E2 Rifle of the following improvements:<\/p>\n

\"MilSurp:<\/a>

Cover of the TB 9X-115 manual on the T20E2 rifle. Courtesy of R. Blake Stevens.<\/p><\/div>\n

\u201cFurther tests of the T20E1 Rifle by the Infantry Board and the Marine Corps Equipment board resulted in the incorporation in the T20E2 Rifle of the following improvements:<\/p>\n