[Rich D]

I have a 928,000 SA CMP SG M1, and it has a M(W?) on the op rod near the handle. It's a 35382 6 SA rounded rod which is correct as far as I can find. Could the M stand for match, as it is marked in the same place as my later NM rod?

 

[Orlando]

No, the only National Match op rods are 77 series and were manufactured in the early 1960's

 

[Orlando]

Its either a inspectors mark or Magnetic particle inspection (magnafluxed) that didnt get removed, not sure anyone knows for sure. You will occasionally see the DOD "Eagle & Stars" stamp on HRA op rods that was supposed to be removed before final finishing

 

[krdomingue]

It is a test mark. Magnetic Particle Inspection looks for flaws in the part. Also called Magnaflux. Uses a magnetic field and iron particles. Any flaws break the field in the part tested and the iron particles will cling there.

 

[Rich D]

Did all op rods go through MPI, and they missed removing the mark on mine?

 

[krdomingue]

I am pretty sure that it was just done on a random basis as a quality control measure.

 

[Orlando]

and they missed removing the mark on mine?

Yes

 

[Phil “Murphy” McGrath]

No, the only National Match op rods are 77 series and were manufactured in the early 1960's

And not all 77 series op-rods were NM marked from SA or RA.

 

[Orlando]

And not all 77 series op-rods were NM marked from SA or RA.

Correct and not all NM op rods were used on NM rifles.They were so common they were used on rebuilds

 

[Orlando]

I went and looked back through my notes and in a Garand Collectors Association Magazine there was a all original 43 Garand that had a SA 6 op rod that had the exact same letter "M" . The article went on to say the meaning of the letter was unknown