M1 Timing Blocks - someone please educate me

[DTC]

Hi All,

I've searched the web and the forum archives and haven't been able to find any technical data on exactly how to properly use the timing block for the M1 Garand.

I bought a homemade machined aluminum timing block on an online auction, but it lacks the engraved instructions/markings that the original steel block had. The Delrin blocks being sold don't seem to have them, either.

I'm just curious what the original block says- and/or would like to see a technical manual/bit of instructions if they exist somewhere.

I'm betting there are several of you here that can point me in the right direction and/or read what it says on yours. Thanks in advance for your time.

ALSO- mine doesn't have the holes drilled in the end of the block. Is a dummy round actually supposed to fit in there? (The holes aren't offset like the cartridges in an enbloc clip would be, anyway...)

Machined Aluminum


Original Steel




Delrin

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[alaska Robert]

From my understanding you insert the timing block into the rifle and the bolt should no release till it gets to the top of the timing block. I don't think the holes make any difference. I have enclosed a photo from my USGI timing gage and a photo from the Garand technical manual. I hope this helps.
Attachment 14062Attachment 14061

[Cajun J]

How do you know which part to replace, assuming bolt is not released. Is this simply trial and error?

[alaska Robert]

Hello Norm, there is a Garand Technical Manual at the website highspeadlane.net . There is a section under malfunctions and corrections that might help or take it to a qualified gunsmith. Here is the link to the manual:
M1 Garand Ordnance Maintenance TM 9-1275

[Rick Cummelin]

How do you know which part to replace, assuming bolt is not released. Is this simply trial and error?

Yes, it's pretty much trial & error, BUT... If your op rod doesn't release as it should, the FIRST part to try is the bullet guide, especially if you are currently using a WWII-type guide. The late-type bullet guides, with the notch, are designed to have a different release point and will "usually" cure a timing problem, at least 60-70% of the time. I always keep several NEW & UNUSED late guides in the part box to use just for this purpose.

[Rick Cummelin]

Since you asked for the markings, here's what is on my GI timing block:

TOP:
US RIFLE CAL 30 M1 & M1C RIFLE
ASSEM 7265698 7265699 TIMING
7319920 B (in a slightly larger font)

RIGHT SIDE:
MUST NOT RELEASE (on the large flat surface below the notch)

MUST RELEASE (on the small flat surface above the notch that protrudes)

To use, simply push in just like you would load a clip of ammo, but more slowly. The bolt SHOULD NOT release before the block has been inserted to the depth of the notch.

However, the bolt SHOULD release when you get to the notch. The protrusion above the notch keeps you from inserting it any further.

My experience has been that very few M1s ever release the bolt early (before the notch), But lots of worn rifles, especially WWII rifles with the early bullet guide, will NOT release the bolt in the notch like they are supposed to. You can even push the block in till it bottoms out a few times, but IF you have a timing problem, the bolt still will NOT release.

This doesn't mean that the rifle won't fire properly--Most still fire & function just fine. This tool is commonly used when a rifle exhibits some malfunctions that are usually attributed to poor timing, like failure to catch the clip on insertion, premature ejection and/or failure to release the bolt (to go forward) when a full clip is inserted.

A clip full of dummy rounds is also useful when troubleshooting timing problems. Lots of worn rifles will fail the timing block test, buit a clip of dummies can be inserted and will eject properly, including the clip with the 8th round.

As I mentioned in my previous post, chnaging old/worn bullet guides and replacing them with a BRAND NEW late-style guide WITH THE NOTCH IN THE SIDE will cure most timing problems discovered by using the timing block.

Hope this helps.

[DTC]

Thanks, everyone. I didn't get the notification and realize ya'll had replied.

My rifle releases EXACTLY at the bottom edge of the notch. I guess the "must not release" on that side of the notch is a bit confusing. Hopefully, they mean on the solid section and not at the lower notch edge.

Will go now and read the links you posted.

[Learmorer]

That is the correct use of the block. The bolt should not release before reaching the bottom of the notch. The bolt should release before the top of the notch bottoms out on the reciever rail. If the timing is "early" you may file, stone, or grind a little off the point on the bullet guide where it contacts the accelerator lever. Be careful here, a litte bit goes a long way due to the leverage added by the accelerator lever. If the timing is slow due to worn parts, replace the bullet guide or other worn part.

The holes through the GI block are to lighten it, they have no other purpose.