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surplusshooter
09-21-2011, 10:31 AM
I have seen N.M. (National Match) rear sights on M1 Garands that were marked on the rear sight base "NM" and some that are marked "NM/2" and they were both marked in yards not meters. Can anyone tell me what the difference is ? Thanks.

Unclenick
09-21-2011, 11:27 AM
Good question, and I'll be interested to hear a reply from someone who actually knows. It might have to do with whether or not they have the standard windage thread for 1 moa clicks, or have the 1/2 pitch thread for a matching knob for 1/2 moa clicks. But I'm just speculating. You can see the thread difference by looking in the right side of the base, though.

pro-nra
09-21-2011, 12:10 PM
To piggy back on the OP NM question, I’ve noticed that on my NM hooded rear sight there is a notch and you can turn the hood to either the 12 o’clock or 6 o'clock position. I though I read somewhere that it will raise the elevation by MOA? My questions is, to raise it by MOA, do I turn the notch to 12 o’clock or 6 o'clock position?

Unclenick
09-21-2011, 01:15 PM
The notch is on the high side of the .004" eccentric hole, so notch at 12:00 is a 1/2 moa up.

kraigwy
09-21-2011, 02:10 PM
The NM sights on the M1 are the same as the M14.

Elevation is obtained by rotating the eye piece up or down. Say the notch is up and you want to come down 1/2 min. Simply turn the notch down. If the notch is up and you want to come up 1/2 min. Turn the notch down then click up one click.

As to windage. There is notches spacers to get the clicks for the sights. Changing it, to give you twice as many notches gives you your half minute clicks.

National Match Sights may or may not have NN stamped on them. The best way to tell, short of shooting the rifle is to mount a dial indicator on the rifle. Click the sights and see how much they move.

The sight radius of the M1 is 27.75 inches. To move the impact one inch at 100 yards you need to move the sight .0077.

So if the dial indicator shows .0077 movement per click, then you have 1 min. clicks. If the dial indicator shows a movement of .003385 then you have 1/2 min clicks.

I've seen 1/4 min (rear) sights on a M14. Again they just changed the disk. However I was never able to shoot good enough to worry about 1/4 moa in High Powder, besides with the half min clicks, I had enough numbers to worry about.

Mark H
09-21-2011, 02:32 PM
"Real" NM sights also have 64 TPI on the windage knob and sight base. USGI has 32 TPI.

Mark

surplusshooter
09-21-2011, 06:57 PM
Does anybody know the answer to the original question: "What is the difference in NM sights marked "NM" and "NM/2". ????

m1bondo
09-22-2011, 01:53 AM
IIRC, NM/2 bases had a larger radius cut to allow for full depression of a hooded aperture.

surplusshooter
09-22-2011, 08:34 AM
Hey "m1bondo", thanks for answering my original question. I think you are right now that I think about it, all of the M1 Garand rear sight bases that I have seen that were marked "NM/2" also had hooded apertures. Now, this brings up another question, but I think I know the answer to this one. I have seen rear sight bases marked "NM/2A". I think these were the bases made for the M-14 National Match rifles and were marked in meters on the elevation knob. Am I correct on this ?

JimF
09-22-2011, 09:28 AM
Hey "m1bondo", thanks for answering my original question. I think you are right now that I think about it, all of the M1 Garand rear sight bases that I have seen that were marked "NM/2" also had hooded apertures. Now, this brings up another question, but I think I know the answer to this one. I have seen rear sight bases marked "NM/2A". I think these were the bases made for the M-14 National Match rifles and were marked in meters on the elevation knob. Am I correct on this ?

Yes, you are!

AZ ED
09-22-2011, 10:07 AM
Very interesting....................................... :D AZ ED out.

Rolling Thunder
09-22-2011, 11:57 AM
Hey "m1bondo", thanks for answering my original question. I think you are right now that I think about it, all of the M1 Garand rear sight bases that I have seen that were marked "NM/2" also had hooded apertures. Now, this brings up another question, but I think I know the answer to this one. I have seen rear sight bases marked "NM/2A". I think these were the bases made for the M-14 National Match rifles and were marked in meters on the elevation knob. Am I correct on this ?

All the variations of NM marked rear sight bases are originally M1 rifle. You are correct on the metric marks: M14. The M1 sight knobs were not originally marked in meters but they can be used.

It's all right here:

http://www.thegca.org/pdfs/Evolution_of_National_Match_Rifles_SA.pdf