Garand op rod.

stevejones

stevejones

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I am new to Garands. I field stripped and greased mine for the first time last night. I noticed the op rod is not perfectly straight. Instead there is a slight curve to it. I put it back together with a sinking feeling but thought i should consult the knowledgeable folks on this forum.

Thanks eveyrone. Steve.
 
The op rod was deliberately bent following manufacture and before installation in a rifle. Do not attempt to re-bend or straighten it.

Do the "tilt test" to verify correct op rod fit. To do this remove the rifle from the stock and remove the action internals incl follower arm pin, follower, follower arm, op rod catch, bullet guide, follower rod and op rod spring. Leave the op rod and bolt in place. Do not remove the gas cylinder or handguards. With the rifle in this condition tilt the muzzle up to a 60 deg angle. The op rod and bolt should move freely to the rear/fully open position from the weight of the bolt and op rod alone. Next tilt the muzzle down to a 60 deg angle. The bolt and op rod should move fwd and fully close from their weight alone.

If the rifle fails the "tilt test" further investigation and corrective action is required.
 
stevejones said:
I am new to Garands. I field stripped and greased mine for the first time last night. I noticed the op rod is not perfectly straight. Instead there is a slight curve to it. I put it back together with a sinking feeling but thought i should consult the knowledgeable folks on this forum.

Thanks eveyrone. Steve.
Click to expand...

Short answer, the M1 op rod "is as crooked as a dog's hind leg".


M1 Garand Tilt Test (or how to check the op rod for rubbing)

http://www.youtube.com/watch?v=tlIoxbtdPXY

Inspecting your M1 Garand

http://www.garandgear.com/m1-garand-failure-to-fire/86-part-inspection

Why Live With Your Old, Worn, Bent, Out-of-Spec or Damaged Op Rod?

op rod repair services

http://www.columbusmachine.com/oprod.htm
 
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IMPORTANT - Make sure you shoot your Garand with the appropriately loaded ammunition or you will really have your op rod bent in a way tht you will not like. The Garand gas system takes a bit of gas off near the muzzle when fired. A slow burning powder in a reloaded cartridge or too heavy a bullet can increase the pressure inside the barrel and put too much pressure on the op rod, resulting in a rod bent out of shape.
 
Some caveats when reloading for a Garand;

-use a reloading manual
-only use IMR4895, IMR4064 or H4895 as these generate the correct gas port pressure to cycle the op rod w/o risk of damage. As a bonus they all yield excellent accuracy.
-use bullets in the 150-168gr range
-always FL resize
-keep brass trimmed below max OAL
-seat primers slightly below flush with the casehead
-don't try to get more than 5 firing cycles out of a piece of brass

For proper functionality apply grease to all specified grease points and make sure that the op rod spring is not broken or badly kinked and is within the specified length of 193/4-201/4 inches.
 
If a rifle fails the tilt test... what can be done? Can a bent Op Rod be straightened and still provide safe service?
 
Cam_S said:
If a rifle fails the tilt test... what can be done? Can a bent Op Rod be straightened and still provide safe service?
Click to expand...

There can be other reasons for a rifle failing the "tilt test" incl interference of the lower band or front handguard liner with the free travel of the op rod. In rare cases the barrel may be installed off top dead center index which will cause the op rod to bind in the gas cylinder or with other parts. If the op rod binds when the rifle is assembled there may also be interference with the stock or stock ferrule. An op rod can be re-bent, but this is a challenging job which takes a lot of patience and trial bending and fitting. I've re-bent a few for proper fit. All other things being equal, its best to try another op rod for correct fit. Pay attention to the lower band as it can be loose or off center. Correct a loose one with another or try a roll pin, rather than the solid lower band pin.
 
I believe the sealed gas cylinder and location of the gas port so close to the muzzle is what makes these some of the most accurate semi auto battle rifles ever made.
With all that #### hanging off the barrel and so many big moving parts they should not shoot like they do....lol
 
Thing is, at the instant of firing, all that iron crap is standing still, just hangin' off the barrel, adding weight and damping vibration.

Gas take-off is just behind the muzzle, so the bullet is GONE by the time the Op Rod starts back, unlocking and carrying the Bolt.

And THEN you look at ALL that damned IRON in that Barrel..... and you start to understand that John Garand really knew his onions.

As to accuracy, I have only one Garand. Got it unfired, a 1953 Springfield. First time out, it shot a .5-MOA group, using the corner of the front sight.... and that is VERY difficult to beat. I shoot it very little because it is so much better than I am. Serious.
 
As long as everything is consistent (tight where required) from shot to shot they shoot very well indeed considering the comparatively slender barrel. A few accuracy detractors to look for when setting up a Garand for accuracy;
-barrel excessively worn or metal fouled
-sloppiness in the rear sight
-loose gas cylinder on barrel splines
-loose lower band
-lack of tension/clamping pressure when the trigger guard is closed
-fore and aft movement of the receiver in the stock
-lack of clearance between the face of the receiver and the rear handguard
-tight fitting front handguard
-op rod rubbing in stock channel, against stock ferrule or inside front handguard liner
-loose stock ferrule
-cracked inside face on gas plug
-loose gas plug
 
purple said:
The op rod was deliberately bent following manufacture and before installation in a rifle. Do not attempt to re-bend or straighten it.

Do the "tilt test" to verify correct op rod fit. To do this remove the rifle from the stock and remove the action internals incl follower arm pin, follower, follower arm, op rod catch, bullet guide, follower rod and op rod spring. Leave the op rod and bolt in place. Do not remove the gas cylinder or handguards. With the rifle in this condition tilt the muzzle up to a 60 deg angle. The op rod and bolt should move freely to the rear/fully open position from the weight of the bolt and op rod alone. Next tilt the muzzle down to a 60 deg angle. The bolt and op rod should move fwd and fully close from their weight alone.

If the rifle fails the "tilt test" further investigation and corrective action is required.
Click to expand...

is this the same with the M14
 
Can someone post a picture of a Garand OpRod showing the correct bends and where they should be located?

Also some pics of bad pistons and lugs would be appreciated.

Thanks!
 
The bends in the tube portion of the op rod are quite subtle and correct fit cannot be judged by eye. You basically need to trial fit one and see if it is a go or no-go for a particular rifle. An op rod that fits one rifle may well not fit another. Minor bend differences in the tube or handle part of the rod as well as dimensional changes or wear on a bolt lug or the bottom of the barrel might make a difference in fit.

The op rod piston should be round in profile and should measure .525 diameter on a dial caliper.

Bad lugs on the rod can show excessive wear on one lug or burring where it engages the op rod catch. Burrs can often be smoothed off. Worn lugs or a worn tab which engages the slot in the receiver can be built up with TIG welding and re-ground to the correct dimension. The Kuhnhausen Shop Manual gives correct dimensions for most parts.
 
Most common cause of burring, wear and damaged lugs is failure to GREASE the thing as per the Manual.

Next most-common cause of battering is a weakened Recoil Spring which has not been changed-out. Garand action is supposed to be STIFF.

I have worked on 'way too many of the things, all from the same causes.
 
Min/max on the op rod spring is 193/4-201/4 inches. Avoid the use of the extra long op rod springs which are sold by Wolff and some others. If you have an overly long one you can cut down the coils on the wide end with a Dremel wheel and then smooth out the tip with a file. One of the hazards of a weak/broken op rod spring, in addition to causing feeding malfunctions, is that the bolt will batter the rear of the receiver and cause it to crack or break out-a real safety concern. A while ago someone had a pic of a cracked receiver heel on this forum and was asking about having it welded. DO NOT even think about this. In addition to all other specified grease points, the op rod spring should be given a light coat of grease to prevent premature wear and allow smooth functioning. Just put some on your thumb and forefinger and run along the length of the spring.
 
About 20 years ago I bought a Garand at an auction. I hadnt inspected it beforehand, so I was not aware of the badly cracked heel that Purple describes.
I have been reluctant to fire it ever since due to this. However, I just ordered a stripped receiver from SFRC last week, and hope to transfer all the bits from one to the other.

The gun was actually from a movie armourer, and I was unaware that there was a set-screw threaded into the muzzle to restrict gas flow to allow blank firing.
My original theory was that the hole drilled thru the set screw was too small at first, and the gun got over-gassed and drove the bolt into the heel too hard.
Now after reading purple's post, I wonder if they cut the mainspring to lighten it for blank use.
 
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