Typo II op rods come up for sale now and then, it should be feasible to use one of those as is or for a template.
M14s barrel fits onto a Garand receiver
- Thread starter Grizzlypeg
- Start date
Typo II op rods come up for sale now and then, it should be feasible to use one of those as is or for a template.
The cheapest method might be to weld up the cam surfaces of an M14 op rod and re-machine them to fit the smaller garand bolt's non-roller op rod cam lug.
https://weaponsguild.com/forum/index.php?action=dlattach;topic=2347.0;attach=25035;image
https://weaponsguild.com/forum/index.php?action=dlattach;topic=2347.0;attach=25035;image
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I agree. I am looking to see if I can source tubing to replace the m-14 rod part. It seems like a shame to destroy an m14 op rod just for the tube that fits the guide.
I now have all the parts to build one. Just a matter of thinking it through, and deciding how to do it using the minimum number of hard to source parts, or tricky modifications that have a chance of failure.
I plan to re-use my Gi issue fiberglass m14 stock. It should be easy to modify, and I hate to see it go to Trudeau's shredder.
I also see that the feed snout at the tip of the chamber of at least one of my m14 barrels sticks out too far for the garand bolt to close. It will need a little trimming on the lathe.
Great news. The M14 op rod tube is 0.586 in diameter, and the Garand op rod tube is 0.500. The M14 tube is only 5.16" long. I can easily make a new one on the lathe. Cut the tube off the garand op rod, machine a mating stub onto the end, and slide the new tube over it, weld the seam. No point scraping an M14 op rod to source a 5" tube I can machine up. Wall thickness of the Garand tube is approx 0.060".
What would be really sweet would be to find a thin wall tube with an inner diameter of 0.500". Then it could be slide over the Garand tube and machined down to 0.586 to fit the M14 op rod guide.
Aircraftspruce has 5/8 diameter 4130 (0.625) tubing with an inner diameter of 0.495". I'd only have to take 0.0025" off the thickness of the garand tube to fit it over.
Or drill out the tubing to 1/2" inner diameter with a long drill bit. Princess auto has 1/2" cobalt bits, 8.5" long for $15.00
Garand on top, assembled M305 on bottom.
What would be really sweet would be to find a thin wall tube with an inner diameter of 0.500". Then it could be slide over the Garand tube and machined down to 0.586 to fit the M14 op rod guide.
Aircraftspruce has 5/8 diameter 4130 (0.625) tubing with an inner diameter of 0.495". I'd only have to take 0.0025" off the thickness of the garand tube to fit it over.
Or drill out the tubing to 1/2" inner diameter with a long drill bit. Princess auto has 1/2" cobalt bits, 8.5" long for $15.00
Garand on top, assembled M305 on bottom.
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So I torqued an M14 barrel onto my Garand receiver, and it comes up 11 degrees short of indexing correctly. That means i need to remove .003" from the shoulder to have it index right (at 3.6 degrees per thou on a 1/10" pitch thread). Both norinco barrels I tried, come up short of indexing correctly in the Breda Garand receiver.
That also means my chamber will shorten by .003". Currently a no go gauge that is .004 over a go will just close the bolt. So, I should wind up at least .001" over go gauge.
So, this weekend I will chuck the barrel up in the lathe and remove .003 and see how the receiver indexes, and what the head space works out to be. I'll set the barrel up through the chuck and use a spider on the back end of the chuck to get the barrel shoulder correctly positioned and aligned. I'll check the bore with a range rod and see how good of a job the norcino barrel's shoulder was cut perpendicular to the bore.
That also means my chamber will shorten by .003". Currently a no go gauge that is .004 over a go will just close the bolt. So, I should wind up at least .001" over go gauge.
So, this weekend I will chuck the barrel up in the lathe and remove .003 and see how the receiver indexes, and what the head space works out to be. I'll set the barrel up through the chuck and use a spider on the back end of the chuck to get the barrel shoulder correctly positioned and aligned. I'll check the bore with a range rod and see how good of a job the norcino barrel's shoulder was cut perpendicular to the bore.
Yes, I believe they are both chromed chambers, so there is no reaming possible for adding chamber depth. Perhaps a thou or more could be added through lapping the bolt though.
I can try a third barrel I have. I don't want to stretch the threads trying to torque the barrel to 300 ft -lbs to get it to index. A light cut on the barrel shoulder will take some time to set up, but be the best solution.
The barrel I am currently working with, was beyond no-go when installed on the M305 receiver. I seem to recall that with the norinco bolt it measured around .007 beyond a go gauge. It was much tighter though with a Winchester bolt I was using in the Norinco.
rifleman762
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Drilling a hole just 5 thou bigger is probably going to cause trouble. This is a job for a reamer. You could take a 1/2" chucking reamer, cut the shank off and braze on an extension that is under 0.5" diameter to fit down the hole.
I've been thinking of picking up an Italian garand receiver to use some of my m14/305 bits on. Figured i could make a decent, oic legal bm59 semi clone. - dan
Set the barrel up on the lathe and took a couple thou off the barrel shoulder. Still took 150 ft-lbs torque to get the barrel to the correct position. Go gauge fits, no go doesn't. Looks like the headspacing is good, better than when the barrel was installed on the M305. Next step is the Garand op rod modification. It pains me to cut it. I'm likely going to just machine my own piece of hollow steel to fit in the m14 op rod guide, and weld it to the garand op rod, with its tube section cut off. I'll machine a little step / overlap where the new piece joins to the old.
Starting to think that retaining the M14 op rod spring would make the most sense, as it was designed for these shorter dimensions. It is a larger diameter spring than the Garand's, and would require the tube to accomodate it. Clearance of the spring and spring guide close to the op rod catch area would be an issue.
A Tanker Garand spring is going to be made for operation with a greater overall length, as the op rod tube is longer than this setup, so both its compressed and extended length is going to be greater than the m14 setup. From what I've read, fatigued springs can cause all sort of malfunctions, and over powered springs as well. So getting it correct is essential to correct operation and longevity of the receiver.
The maximum space for the spring at compression (bolt fully to rear) is approx 5.7"
A Tanker Garand spring is going to be made for operation with a greater overall length, as the op rod tube is longer than this setup, so both its compressed and extended length is going to be greater than the m14 setup. From what I've read, fatigued springs can cause all sort of malfunctions, and over powered springs as well. So getting it correct is essential to correct operation and longevity of the receiver.
The maximum space for the spring at compression (bolt fully to rear) is approx 5.7"
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Some pics of the M14 op rod and the cut down Garand op rod. The Garand op rod has the machining (bright area) on the tube to clearance it for the op rod guide when the op rod is fully forward. The Garand op rod also has the hooks for the op rod catch that operates when the bolt is held back after the last round.
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