Rifleman Q&A: How Do I Avoid 'M1 Thumb?'

posted on March 24, 2021
** When you buy products through the links on our site, we may earn a commission that supports NRA's mission to protect, preserve and defend the Second Amendment. **
thumb.jpg

Q: I remember hearing the term “M1 thumb” used by my uncle, who carried an M1 Garand during the Korean War. More recently, I’ve seen it mentioned in the pages of this magazine. What exactly does this term mean?

A: After firing the last round from an M1 Garand, the empty en bloc clip is automatically ejected and the bolt locks back, exposing the open receiver. To properly reload the Garand, another eight-round clip is pushed down into the receiver using the thumb of the shooting hand, while the outside edge of that same hand is pressed back against the operating rod handle to keep it from flying forward.

Once the clip is fully inserted, the spring-driven bolt unlocks but is prevented from moving forward because it is still being held back by pressure from the hand. The thumb—and, in fact, the entire hand—is then quickly raised up out of the way, and the bolt is allowed to slam forward, chambering a round in the process.

But sometimes a shooter does not move the thumb fast enough before releasing the bolt, which happened in training or even combat to some G.I.s, or the bolt does not lock completely open, and it slams forward prematurely.

Either way, the bolt can smash into the thumb, resulting in what has become known as  “M1 thumb,” which is not only painful, but embarrassing, and can result in a blood-blackened or shattered thumbnail. In recent years, the term “Garand thumb” has also been used to describe this unpleasant situation. No matter what it’s called, Garand shooters and collectors should obviously try to avoid it.

Note: The latest device designed to alleviate “M1 thumb” is made by Mountain Aerospace Machining and is available at m1thumbsavers.square.site—The Eds.

Latest

Stuart 45 Pistol Pre War Manuevers Web Main
Stuart 45 Pistol Pre War Manuevers Web Main

Guns Of The U.S. Tankers In World War II

Since the end of World War II, debates have raged about the effectiveness of American armored fighting vehicles in that conflict. Despite all the Monday morning armored quarterbacking, American AFVs were war-winners, driven to victory by some the finest fighting men our nation has ever produced.

MidwayUSA Foundation Awards Over $14 Million In Cash Grants In 2025

In honor of National Shooting Sports Month—held annually in August—along with the growing popularity of the sport with new participants, MidwayUSA Foundation announced it has distributed more than $14.2 million in cash grants to support youth shooting sports in 2025.

Making The KelTec PR57 In Wyoming

To make its PR57 handgun, KelTec invested in an entirely new manufacturing facility located in Rock Springs, Wyo. "American Rifleman Television" headed out for an inside look at the company's efficient production process.

Taurus 66 Combat: A New "Fighting Revolver"

First introduced in the 1970s, the Taurus 66 Combat is a medium-frame revolver that has seen several evolutions in its lifetime, and the latest update creates what the company considers "the final word in fighting revolvers."

Review: Taurus GX2

From cars to cellphones, as a product gets more sophisticated, it usually also gets more expensive. And, as modern handguns get more modular and optic-ready, their prices tend to go up.

Rifleman Q&A: A Garand Puzzlement

"We are a father-and-son NRA member tandem in search of an answer regarding the branding of an M1 Garand rifle. We own an M1 rifle that has markings indicating it was a “lend lease to England,” and it also has a .308 barrel/sleeve."

Interests



Get the best of American Rifleman delivered to your inbox.