Troubleshooting The M1 Rifle: Bolt Release Timing
February 09, 2015
Give me a Garand, a pocket full of clips and a place to shoot it, and I'm a happy man. The M1 is easy to shoot, reliable and accurate. Unfortunately, these rifles are 60 to 70 years old, and many saw heavy use with foreign armies before they returned to our shores, so parts wear and breakage is common.
Parts are still relatively plentiful and (in most cases) inexpensive. If your rifle fails to function, your biggest challenge will be finding someone who can fix it. Your average gunsmith who may be great with Remington 870s and Ruger M77s is unlikely to have the knowledge, parts or tooling necessary to repair Garands.
Not a problem. You can probably repair it yourself. Military rifles are designed to be repaired in the field by unit armorers with minimal gunsmithing skills. Parts are interchangeable and disassembly is easy.
Bolt release timing is the position of the clip during the loading cycle at the moment of bolt release. As the loaded clip is inserted into the rifle, pushing the follower down, the follower rod actuates the operating rod catch, releasing the operating rod and allowing the bolt to move forward.
There are half a dozen parts all working together to make this happen. A part that is worn or damaged can delay bolt release, making the rifle difficult to load. The clip will have to be pushed downward into the rifle with more force than normal. We call this condition "late" bolt release.
Military armorers checked rifles for proper bolt release with a special gauge milled from a block of steel in the shape of a loaded clip. A groove was cut into the right side of the block, indicating the release point.
The gauge is inserted into the rifle and the bolt should release when the edge of the receiver is level with the groove. If the block bottoms out without releasing the bolt, the rifle is inspected for worn or defective parts.
Original military gauges are relatively rare, but reproductions are available from Brownells made from Delrin for $38.99. Although the gauge is the best way to determine bolt release timing, a clip of dummy rounds that is marked at the release point in a known good rifle can be used as a substitute.
Once we have determined a rifle suffers from improper timing, it is disassembled and the relevant parts are inspected as follows:
Bullet Guide: This stamped piece of metal is the primary cause of late bolt release. The critical wear area we are concerned with is the little hump in front of the follower arm pinhole known as the "accelerator bearing point". Measure the height of this point with a dial caliper. It should be .179" minimum to .183" maximum. Generally, higher is better.
A shiny spot is usually visible where the accelerator portion of the op rod catch rubs. New guides are available from parts vendors such as Fulton Armory, and it's a good spare part to have in your kit. Expect to pay about $20 for a new one.
The follower arm pin is another high wear part that should be checked. This pin passes through the receiver, op rod catch, follower arm and bullet guide, and is a critical bearing point. I have found that simply replacing this $3 pin will correct the timing on some rifles. The pin diameter should be .156" minimum. Keep a couple spares.
A bent operating rod could also be the culprit, but you can't check it with your dial caliper. A rare, sophisticated gauge is required to check op rods. However, you can borrow a rod from another rifle. If bolt release is corrected and you've narrowed the problem to the operating rod; it can be shipped to Columbus Machine Works for repair. I've sent rods to them on several occasions and their work is exemplary.
Check the follower arm for straightness with a 6-inch scale and check the pivot pin hole in it for size (maximum .162").
Worn parts should be replaced. Modifying parts to adjust bolt release timing will cause other problems. You will need a good bench reference handy when troubleshooting the Garand and I have found none better than The U.S. .30 Caliber Gas Operated Service Rifles: A Shop Manual by Jerry Kuhnhausen, available from Brownells. My copy has served me well since 1995.
A G.I. issue timing gauge. Commercial copies are available. Originals are pretty rare anymore, but Brownells
offers a reproduction made of Delrin that will get the job done.
The timing gauge is inserted into the rifle like a loaded clip and the bolt must release when the milled groove is level with the edge of the receiver. If the gauge bottoms without release, the timing is "late."
This photo shows the bolt locked to the rear. The operating rod catch is fully engaged. A bent operating rod can lead to a variety of problems, including hard loading.