Garand Cylinder Help

[Dave P]

When I re-install the gas cylinder (slide it on by hand) the lock stops at about 12:00. (When I first took it off it this new rifle seemed tighter)

Should I:
A) tap the cylinder on with wood to tighten?
B) tap the lock to tighten?
C) back off the lock 180 deg and be done with it?


I am going to fire it at lunch today for the first time, so I will find out if the gas holes are aligned OK or not, but if the cylinder has slop in it, the sights will also be loose.

What's the right answer?

Thanks guys!
Dave

 

[1911Fencer]

Do you see any 'white' spots or bare metal at the splines behind the where the gas cylinder mates to the barrel? If so, you may be able to tap it on a little further to get the lock to tighten up closer to 6 o'clock.

It shouldn't cause any problems if it's a little further on the barrel. It's quite forgiving. With the cylinder on, and the lock off, you should still be able to see the gas port in the barrel through the cutout in the gas cylinder. As long as that doesn't get covered, you should be fine.

 

[hps1]

Gas cylinder lock should tighten up somewhere between 6 and 8 o'clock for best accuracy. Following from Accurizing the Standard M1, NRA's booklet "The M1 Rifle":

"Standard issue M1 rifles may have gas cyl. locks which, when fully tightened, are located at random positions relative to gas cyl. and must be backed off to the 6 o'clock position. This is within mfg. limitation of standard weapons and is satisfactory. However, it is advantageous for accuracy to select a new gas cylinder lock, which when hand tightened to the barrel shoulder is between the 6 & 8 o'clock position. The lock should then be backed off to align w/gas cylinder. Chamfering gas cyl. lock and advancing the thread travel on the bbl. to achieve 6 o'clock position may affect functioning." (I suspect they are referring to the alignment of barrel gas port with hole in gas cyl. mentioned by 1911Fencer.)

"The gas cylinder lock should not be tightened against the barrel shoulder with force, as excess tightening induces stress on the barrel, may upset mating threads and is detrimental to accuracy."

Enjoy your M1!

Regards,
hps

PS
Go ahead and back off the lock you have for the time being, won't hurt a thing, and keep your eyes open for one which fits your rifle better.

 

[Dave P]

Appears that the lock is bottoming out on its threads, and the cylinder is loose on the splines (before plug is installed) Maybe a little spline peaning is in order? Or find a different/longer/tighter cylinder? Gas holes line up fine, and it functions great!

Accuracy is only OK, maybe 4 MOA at 100 yrds.

Thanks!

 

[hps1]

Recommend the NRA booklet mentioned above ("The M1 Rifle"). It gives easy to understand and follow steps you can take to tighten up your groups on a service grade M1.

Regards,
hps

 

[AZ Jeff]

Everyone offering advice here should be careful to note that there are other factors to consider when optimally locating a gas cylinder on the barrel of the Garand beside cylinder lock "timing".

Under no circumstances should the rear ring of the gas cylinder ever contact the front handguard or it's ferrule when the handguard is seated against the lower barrel band. Such contact will result in major accuracy problems when the barrel and gas system heats during firing.

The optimal axial location for the gas cylinder should be obtained by locating the square hole in the gas cylinder over the gas port in the barrel. Then the gas cylinder lock should be fitted accordingly as others have mentioned. If the gas cylinder is located too far rearward on the barrel, insufficient cylinder volume will be present when the gas cylinder plug is installed, and the gas piston head on the operating rod is in its' forwardmost postion.

It is more important to locate the cylinder according to the barrel gas port than it is to get a gas cylinder lock that "times" to the perfect "7 O'clock" position.

Lastly, any rotational play in the gas cylinder is caused by loose splines, and can be corrected by CAREFULLY peining the spline grooves in the barrel. (A LITTLE tapping goes a long way) Once the splines are tight, the gas cylinder may need to be driven on GENTLY with a wooden block until close, and then drawn down the last bit with the cylinder lock.

 

[Jimmy Mac]

AZ Jeff

Also sometimes you can move the gas cylinder up or down to get a certian type ammo to work in your Garand.

I wound up with a bunch of old Kynoch 30-06 ammo that would short stroke in my rifle. It shot very good but it would short stroke about every other round. Other ammo worked just fine.

I moved my gas cylinder up just a little to give it more "chamber" and this ammo now works 100%.

 

[Dave P]

"Under no circumstances should the rear ring of the gas cylinder ever contact the front handguard or it's ferrule when the handguard is seated against the lower barrel band. "

Jeff, can I eliminate the hand guard rattle with a soft spacer? Like foam rubber stuff between h/g and lower band?

Or now that I think about it, a high temp spacer from the h/g to the bbl might work also?

 

[hps1]

As Jeff pointed out, the upper handguard _must_ have clearance between gas cylinder. As the barrel/gas cyl. heats up the metal expands and will apply pressure to the upper handguard and _will_ change point of impact if this clearance is not maintained.

Accurized M1's have the upper handguard attached to the lower band with two screws and/or glass bedding material. This assebly is pinned to the barrel and will not rattle. The downside is that it is not adviseable to pick up the rifle by the upper handguard once this is done. Rear handguard shall have longitudinal movement, also.

Neither upper or lower hand guard should touch the barrel. The barrel must be essentially free floated for accuracy. I would not put any foreign material in the barrel channel.

Regards,
hps