Grandsons Garand

[gunner312]

I finally got my grandsons garand that you guys helped me build and I really appreciate it.

He will be here next month and I will get to give it to him.

I have a problem with it though. It short cycles. I checked the piston and it measures .526 The Gas Cylinder measures .528.
I put a new recoil spring in it and checked the Gas port size it is .0775. De-burred the sharp edges on the Op rod and the op rod catch.

Checked the stock for interference rubs on the op rod and it appears to be OK.

The bold falls freely from locked position to fully to the rear when the rifle is tilted from vertical to 180 the other way.

It has a new Barrel from criterion.

Help?

Jim Wright
(Gunner312)

[k arga]

have you got a piece of a broken op rod spring stuck in the end of the rod?

[Art]

after you do what k arga suggested clean out the gas port.

[Dan Shapiro]

Other considerations:

Is the gas cylinder lock screw valve stuck open?

What kind of op rod spring? Wolf Competition springs are worthless and cause more problems than they allegedly solve.

Op rod spring free length between 19 1/2 and 20 1/4 long?

Follower rod bent or twisted?

Did you clean out the inside of the op rod using a cleaning rod and patch? A lot of gunk accumulates in there. Once clean, lightly grease (smear in the palm of your hand) the 1st half of the op rod spring that goes down the tube.

HTH

[1563621]

Measure op rod, I had a seller selling them 1/2" short.

[Griff Murphey]

Might be one of those Eytie shortened rods they did for their barrel set-back 7.62 conversion program for the Italian military.

[Sunray]

.526" is a thou too big. Gas cylinder is ok. Gas system dimensions are under Fig 23 of Section 5 under Op Rod. Note the need for the provided UN & PW.
I think the port is too small.
Operating parts which fail to move fully to the rear (short recoil) are caused by:
1.Valve leak in gas cylinder lock screw. (Valve not fully seated.)
2.Defective operating rod spring.
3.Undersized piston. (Caused by the use of abrasives when cleaning the piston.)
http://www.biggerhammer.net/manuals/

[gunner312]

I'm taking the rifle to the range this morning.

Replaced the recoil spring with a new one from Orion 7.

Rechecked the gas port. Still checks at .0775, according to the manual I have it should be good. But I'm taking a .080 reamer with me as that is the max size according to the manual. If it still short cycles I'll ream it to .080 and try again.

Wish me luck.

Does anyone out there have a print of the plans for the recoil spring checking fixture that was in a past issue of the Garand Collectors Journal?

Jim Wright
(Gunner312)

[gunner312]

Went to the range and fired the rile. Still short cycles. The piston is good .5255 Cyl is good at .528 I'm using a 1 slot after market gas (no valve) plug fits tight no leaks as near as I can tell. New Orion 7 Spring. So, I'm just about to the point of reaming the gas port bigger. It presently measures .077(-) with my pin gauges.

So My question is, should I ream to .080 or should I go up to .078 then .079 and then .080 while checking for operation between each enlargement?

The oprod and bolt fall free to full open when I tilt the rifle from horizontal to muzzle vertical.

I do notice that the oprod may be rubbing on the bottom of the stock. I'll clean that out before the next round of testing. I won't ream the gas port till I am at the range.

Or what?

Jim Wright
(gunner312)

[k arga]

what are you using for ammo, seems like you have covered everything, did you check to see that there is not a piece of spring in the end of the op rod. If the op rod is clear should be about 15.75", from who and what barrel do you have?

[k arga]

have you checked to see that the gas cyl is lined up with the gas port, this has to be some what an easy fix, just have to find it.

[Dan Shapiro]

Do the tilt test with the barrel/receiver group in the stock, that will indicate if stock rubbing is causing the problem.

Does the ammo work in another M1?

[gunner312]

Will do the tilt test with the stock mounted. Ammo is LC 63


Jim Wright
(Gunner312)

[gunner312]

checking to see but I believe it lines up good.

Jim Wright
(Gunner312)

[gunner312]

I have a new Criterion barrel. Donated by a friend. The first barrel that was given me was a good one, (ME3/TE5) but this one should/will group better. (If I can cure the short-cycling) The Ammo is LC63 for testing (but the darn thing needs to clean up and shoot soon, I'm down to my last six bandoleers). My Grandson will be using re-loads for a steady fodder (I will be teaching him how to re-load ammo this summer for it). The oprod is clear to the end and I cleaned it out with a brush/oil/hoppe's and greased the oprod spring with fresh lubriplate.

[Dan Shapiro]

Checking Kuhnhausen, gas ports for 30-06 barrels according to specs: .0790"+.0015". Ports should be no larger than .0810".
a #47 (.0785") drill shank can be used as a cleanout tool. A #46 (.0810") drill shank can be used as a max gauge.

[gunner312]

Appears that the gas port is small. .077-, so I'll take it out to .079, reamer ordered today. (also a .080+ reamer)

thanks for all the help & advise.

Jim Wright
(Gunner312)

[dryheat]

ME of three isn't all that great. .308 barrels get the gas port reamed out to .093- Don't worry about the gas cylinder lining up with the gas port...it does.
The tit test just fine tunes the rifles for match shooting...it won't stop an oprod from cycling unless there's part of a limb in the way.

[RIPCORD2]

Just an Idea, but have you checked the alignment to make sure the opening in the barrel and gas cylinder are even so the gas cylinder is not restricting the gas flow?
just a thought.-hope this helps --RIPCORD2