I recently bought a danish m1 garand and finally took it out to the range today and upon firing I found that it was short stroking. The bolt comes back enough to #### the hammer but not strip off the next round. It did this with both federal m1 garand 30-06 and some hand loads I made up. I dont think it's a lube issue, when I got the rifle I went through and cleaned and re lubed everything. The gas screw was tight. So I'm wondering is it a bad op rod spring or an issue with the piston/ cylinder
M1 garand short stroking
- Thread starter Lucite
- Start date
The gas system is a likely culprit for short recoil. This could be due to a worn op rod piston, a worn gas cyl interior or a loose/defective gas cyl screw. You can measure the piston with a micrometer or caliber; it should be at least .525 diameter. The interior of the gas cyl can be measured with a plug gauge of the proper diameter. The gas cyl screw should be tight and the valve should be fully seated. Fouling or dirt can cause the valve to remain partially open. Also, if the face of the gas cyl screw is cracked, it can cause gas to leak.
The gas cyl must also be properly seated on the barrel to permit adequate gas to flow from the gas port into the cylinder. The aperture in the gas cyl must be aligned with the gas port in the barrel and must not obstruct it. Also, the gas port in the barrel must be clear of fouling.
The next thing to check is the op rod spring. It should measure no more than 20.25 inches and be free of kinks. Minimum length is 19.75 in.Some people install aftermarket op rod springs which are too long.
A binding op rod may also contribute to short recoil. To check for free op rod travel do the tilt test. To do this remove rifle from the stock and remove the op rod spring, bullet guide, op rod catch, and follower. Leave the bolt and op rod in place. Hold the rifle in a horizontal position and elevate the muzzle to a 60 deg angle. The bolt should open from its own weight. Next, depress the muzzle to a 60 deg angle and the bolt should close from its own weight.
The gas cyl must also be properly seated on the barrel to permit adequate gas to flow from the gas port into the cylinder. The aperture in the gas cyl must be aligned with the gas port in the barrel and must not obstruct it. Also, the gas port in the barrel must be clear of fouling.
The next thing to check is the op rod spring. It should measure no more than 20.25 inches and be free of kinks. Minimum length is 19.75 in.Some people install aftermarket op rod springs which are too long.
A binding op rod may also contribute to short recoil. To check for free op rod travel do the tilt test. To do this remove rifle from the stock and remove the op rod spring, bullet guide, op rod catch, and follower. Leave the bolt and op rod in place. Hold the rifle in a horizontal position and elevate the muzzle to a 60 deg angle. The bolt should open from its own weight. Next, depress the muzzle to a 60 deg angle and the bolt should close from its own weight.
op rod spring measures 19.75 and appears to be in good condition, gas cyl screw looks to be in good shape, no signs of cracking, gas piston measures .525, gas port is unobstructed. I don't have gauge pins to measure the gas cyl I could always use telescoping gauges and the op rod does appear to be binding slightly just under 3/16 from the end of travel. That being said do I need a new op rod or can I get away with honing the op rod running surface to get it to not bind. Or could it possibly be a lubrication issue, would a potentially heavier weight grease cause issues?
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Check the interior of the stock for op rod rubbing along the barrel channel or against the interior of the stock ferrule. What is the barrel make? A barrel can be undersized in the area around the gas port which will also permit excessive gas to escape
I think people will be scratching their heads over some of these for years to come. There's more to assembling a properly functioning Garand than just cranking the parts together. Its a fairly forgiving rifle, but there are limits.
handofzeus
CGN Ultra frequent flyer
- Location
- Trout Creekish Ontario.
Don't dismiss the ammo factor either. Although not as crucial as properly fit parts and seals, a different powder with different bullet weights COULD mung things up.
Doesn't appear to be any signs of the op rod rubbing on the stock but it does look like it's rubbing on the stock ferrule near the end of travel. No idea on barrel make but it doesn't look like there is any gas blow by around where the gas cylinder and barrel mate its also a fairly snug fit.
Is there a way to tell with the danish M1's, from looking at the parts they seem to be Italian in origin, serial's are non matching though.
I mean it's a possibility but I feel it's closer the the unlikely side of things. It wouldn't cycle with federal 150gr M1 garand ammo and the loads I made up were 168gr hornady bthp match bullets over 46gr of varget
The "D" numbers on each part refer to the Drawing number for the part. So if there is a revision the "D" number will change too. For example this site ht tp://usriflecal30m1.com/Parts/PartsMFG.aspx?mfg=SA
example:
MFG- SA
Component- Bolt
Drawing Number- D6528287-SA
Heat Lot- A-10
Date Range- January/1952 to December/1954
Serial# Range- 4240000 - 5329999
So I used some inletting black to see where the op rod was contacting the ferrule and I found that not only was it rubbing on the ferrule but it was rubbing on the stock in a couple spots. So I took a chisel and dealt with the high spots on the stock and filed down the ferrule a bit where it was contacting, I'm also thinking I'll but some grease on the ferrule to help things slide a bit better and see if that fixes the issue.
Gas port diameter is also critical to functioning. Max gas port diameter for a .30-06 Garand is .081 (#46 drill shank). You can use a #45 drill shank (.082) as a no-go gauge. A #45 drill bit (.0785) can be used as a clean out tool.
Anything could be possible I suppose but unfortunately I don't, and the more I look at the rifle the more I'm thinking it was build that was done by an inexperienced builder because overall everything is in excellent condition and when I first tore it down it was honestly the cleanest milsurp I've ever been into. At any rate I'll see if what I've done fixes the issue and if not I'll explore other possible fixes. Worst case scenario I have to take it to a gunsmith and have them look at it.
If the rifle passes the tilt test then the fit of the op rod is OK. Having the rod rubbing on the side of the barrel channel or against the stock ferrule does happen and can be easily remedied by sanding/filing the stock or ferrule to relieve contact. Putting a film of grease on the ferrule will show if the op rod is still making contact.
Interference with the op rod is bad for accuracy as well.
Interference with the op rod is bad for accuracy as well.
Brutus
CGN Ultra frequent flyer
I have a Springfield M1 with a Danish VAR barrel. It was once military issue because the Danish armorer placed a small sticker underneath the barrel but on the upper side of the forestock so it's viewable when you remove the barreled action from the stock.
IIRC it was last inspected in 1993 and the 300 meter zero was 13 clicks up from lowest elevation setting.
IIRC it was last inspected in 1993 and the 300 meter zero was 13 clicks up from lowest elevation setting.
Measured the gas port with a caliper and it comes out to .080
If that's the case then it's a build gun.
UPDATE:
So as I was reassembling the rifle I decided to go over it again with a fine tooth comb and I think I found the issue. When I originally checked to see if the gas port was unobstructed I though that it was clearing the opening in the gas cylinder. Turns out it was partially blocked by the gas cylinder opening because the gas cylinder was sitting too far forward due to the front hand guard not being fitted properly, so I took about 1/32 off the back of the hand guard where it fits into the ferrule and I now have 100% clearance of the gas port.
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I have built about 10 of these rifles most with NOS parts I had 1 that would not cycle 100% of the time it took me weeks to figure out by replacing 1 part at a time with known to me good parts turns out the follower arm which I removed from a sealed package for the 50's had a very slight bend tried to straighten it ended up replacing it and problem solved
