Enter your email address to receive notifications of new posts by email.

The Vault

T25

During the late years of WWII, the US military worked diligently on a replacement for the M1 Garand rifle, which was designated the T20. This was basically an M1, with the addition of a trigger group allowing full automatic fire and with a 20-round box magazine in place of the M1′s 8-round clips. As long as the war continued, this project was pursued with some sense of urgency, and rifles were being actively tested in 1945 and late 1944. By May of 1945, the Ordnance Technical Committee actually recommended procurement of 100,000 T20E2 rifles – a sure step towards their general adoption. However, the war ended a few months later, and the project was no longer particularly time-sensitive. The large order of T20s was not formally placed, and the immediate plans to replace/update the M1 rifles in service were all shelved. Instead, it was decided to pursue a new lightweight rifle program based on the developmental T65 cartridge (which was to become the .308 Winchester and 7.62 NATO). The Olin Corporation had developed a new type of ball powder which would allow the Army to duplicate the performance of the .30-06 cartridge with a half-inch shorter case. This was seen as a valuable way to reduce rifle size and cost.

The head of US small arms R&D, Colonel Rene Studler, anticipated this change of focus, and in March of 1945 he assigned a 37-year-old designer named Earle Harvey to study the characteristics of military breech locking systems and develop an ideal light rifle. Harvey had been toying with designs in his own time since 1942, and he dove right into the project. By the end of 1945 Harvey had a completed design for what would be known as the T25:

Harvey Earle's T25 automatic rifle

Harvey Earle’s T25 automatic rifle, without magazine (photo by Springfield Armory National Historic Site)

Harvey was a skilled designer, and his previous work included a new gas system for the M1, which was made as the experimental M1E9, and would eventually be used in the M14 rifle. He used that gas system in the T25, along with a tilting bolt mechanism which locked into the top of the receiver (somewhat like a Bren LMG). Since the force of firing would push this type of bolt directly back against the locking shoulder in the receiver is would put the bolt in compression. A rotating bolt like the M1 used, by comparison, puts a large shear force on the bolt’s locking lugs, which requires tougher steel and more machining to construct. Harvey judged that his tilting bolt would be both stronger and cheaper than the M1 bolt – and was right, too. In a firing test on May 18, 1948 the T25 was found to withstand chamber pressures of 125,000 psi without an increase in headspace, and pressures of 150,000psi without any parts breakage.

Harvey Earle's T25 automatic rifle

Harvey Earle’s T25 automatic rifle (photo by Springfield Armory National Historic Site)

Harvey also considered several other important factors in his design, including simplicity of manufacture. Given the new nuclear dimension of warfare, the component parts of the T25 were designed to be fabricated with generalized tooling and machines as much as possible, so that production could be distributed to numerous small shops in case of a nuclear strike on the US. Harvey was also very conscious of weight in the rifle, and made use of aluminum and deliberately lightened designs for parts not under direct stress (like the buttplate and trigger guard). The result was a full-power rifle (it was chambered for the 7.62mm T65 cartridge) weighing a mere 7 pounds (unloaded) – a significant technical accomplishment. To mitigate the recoil from such a light overall weight, the design utilized an in-line stock and muzzle brake.

The first four prototype T25 rifles were made under contract for Springfield Armory by the Bennel Machine Company out of Brooklyn, and first completed rifle was test fired in January 1948. A more formal endurance test in April 1948 saw 3500 rounds put through gun #3, with no parts breakages or weakened components. By August, Col. Studler was contracting with Remington for more prototypes to be made (12 were delivered in December 1949, having been delayed several months by design changes). Another 110 were ordered in the summer of 1949, although this quantity was shortly revised to just 50. Production of these early guns was repeatedly delayed by changes requested by the Springfield Production Engineering Branch, as being necessary to make the rifle practical for mass production.

In actual fact, the T25 was no more complex to manufacture than the M1, and the delays to prototype production were founded in an administrative bias at the Armory again new development, rather than actual shortcomings of the T25 design. The final lot of rifles made be Springfield Armory was finally delivered in the summer of 1951. This bias against the rifle would come back to haunt the T25 as one of the main reasons behind its cancellation…

Army testing of the T25 began in September 1948 at Aberdeen Proving Grounds, and the results were quite good. In the first test, the T25 was found to be more accurate than the M1 rifles used as a baseline, and to operate well under adverse conditions, considering its current level of development. Problems were reported with firing pin breakage and erratic ejection patterns, but nothing was particularly surprising or could not be fixed with some more work. In 1949, the decision was made to also restart development of a lightened M1 rifle, and for the following three years (1949-1951) that project would run parallel with the T25.

The next Aberdeen trials were in February, May, and June of 1950, with the T25 competing against the FAL and EM2 rifles (both in .280 caliber). The T25 showed some weakness in some adverse condition tests, but outperformed its European rival in others. It did have problems caused by poor-quality ammunition, as the batch of T65 ammo supplied for the testing gave erratic pressures. It also had problems with some improperly parkerized parts, and performance improved in the last parts of the testing after these parts had been replaced. Overall, the T25 was a fundamentally sound rifle in need of more development work. Earle Harvey was the only engineer assigned to the T25 project, and he had significant other duties as well. The quality of the rifle is particularly impressive considering the limited time and money that was allocated to it, and it reflacts very well on Harvey’s skills as a designer.

Ultimately, internal administrative bias towards the existing M1 rifle led Col Studler to decide to drop the T25 program late in 1951 or early in 1952, although this decision still had to be made to look like a fair and objective choice. Another round of testing was scheduled for 1952, to include the T25, T44 (Springfield’s product-improved M1, which would eventually become the M14), the Belgian FAL, and the British EM2. Harvey was unable to get the time and engineering assistance necessary to iron out the issues with the T25, as intended by Ordnance Department higher-ups, and the result of the testing was the T25 (and EM2, for what it’s worth) being formally dropped from consideration.

For all the work and political maneuvering of the T25 and T44 (and the other shorter-lived experimental rifles of the period, including the roller-locked T28 and John Garand’s bullpup T31), the program was ultimately doomed to failure. The entire premise of the light rifle program since its inception in the autumn of 1945 was to devise a single standard rifle which could serve as light machine gun, rifle, carbine, submachine gun, and sniper rifle. It became clear to Harvey and the other designers, as it should have been clear to everyone, that the requirements were contradictory and impossible to fulfill. A 7-pound weapon using a full-power cartridge could never be an effectively controllable LMG, and the same gun would yet be too large and heavy to be an effective replacement for the M1 Carbine. The T25 was repeatedly found to be too light to be controllable in full auto, but the design requirement was never altered. This giant elephant in the room of the light rifle program was studiously ignored clear through the adoption and mass production of the M14 rifle, and only really addressed with its replacement by the M16.

9 comments to T25

  • The least successful general-issue rifle ever. Sad.

  • Nat

    Really interesting design, with obvious FG-42 influences. I wonder if anyone has ever tried to reproduce any of these old prototypes? You could design a custom stock for standard M1 Garand, and install sights like this. I once saw a special stock that makes an M1 Carbine look like a Thompson.

  • CaptEndo

    Anyone know where blueprints for the t-25 could be found? I’m intrigued by the possibility of a semi auto version!

  • Chris Brosnahan

    There is and excellent book on US small arms development and acquisition called “Misfire” by William Hallahan. Much or the troubles were due to the Board of ordnance in its different iterations, refusing to accept new ideas & technologies and when finally doing so, ruining the process with micromanagement, the “Gravel Belly” attitude, penury and just plain ignorance. A good read.

    CB in FL

  • Robert E. P.

    I’m also interested in seeing those blueprints… Anyone know if the T25 influenced the design of any other guns, civilian or military?

  • Bob Mandel

    I have always wondered why the 6mm was never considered.I know in the late 19th century the USN used a 6mm Lee rifle and found it not powerful enough.But with modern powders a 6mm(243/244) could fire 110gr bullets at 3000fpm and make for a very deadly round out to 500yds.The 243 is a very popular medium game round and it seems to me that its smaller size and weight would make it possible for infantry men to carry about the same amount of ammo as they do for the 5.56 round.Has the 6mm ever been proposed?

  • Vincent S.

    I can imagine if the Board ever understood that a 7 pound rifle firing a full powered cartridge won’t be very controllable in full auto and didn’t have such an anachronistic erection for a rifle designed in the 30′s (maybe even actually going back to the original development of an intermediate 7mm), the T25 or its conventional stocked T47 would have become a pretty nifty service rifle. Shame it never got the chance to fully mature.

  • Black Talon

    so the t25 was a short stork gas piston with a tilting bolt that was lighter than a rotating bolt gun. someone should make a semi auto version, he would make a lot of money.

    and it looks like the tilting bolt is both stronger and cheaper than the rotating bolt. so why is the rotating bolt system much more popular as to be the dominant locking mechanism for gas operated guns? is it because bolt action rifles are rotating bolt and so there is a bias among fire arm designers for rotating bolts?

Leave a Reply

  

  

  

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>