New to me M1 rear sight wiggles - Page 1

[ARCHIVED THREAD] - New to me M1 rear sight wiggles

Posted: 6/27/2018 1:04:02 AM EDT

I got a 1943 M1 yesterday.
While at the range today I noticed the rear sight appeture wiggles left / right. It also caused a couple of fliers way off from the rest of the groups.

A little research shows a few remedies, one being using a Center punch to peen the side to make it fit in there tighter. Does anyone have pics of the peening to show where to hit it ?

Or, do I just buy a replacement or two and hope one is nice and tight ?

Attached File

Posted: 6/27/2018 1:07:14 PM EDT

[#1]

Where did you get the rifle? Type II lockbars I see...do you mind posting some more info on the rifle??? (Make, SN, barrel date...etc) Stock looks to be in amazing shape - curious if you have something close to "correct." Almost all lockbar sights were replaced with the TE105 during post-war arsenal rebuilds.

I wouldn't mess with what you have. It could hurt the potential high value.

Posted: 6/27/2018 3:12:02 PM EDT

[#2]

Got the rifle from a customer. He some how got it from his wife’s mother’s cousin who was in WW2 and the Korean War.

It’s a April 1943 receiver with a 1951 Barrel in excellent shape

Posted: 6/27/2018 3:14:10 PM EDT

[#3]

The sling is also dated 1943

Attached File

Posted: 6/27/2018 3:16:54 PM EDT

[#4]

Does the stock have any cartouches? Does the oprod have a relief cut?

Interesting that it went through a rebuild and got a new barrel but still has original sights.

Posted: 6/27/2018 3:32:07 PM EDT

[#5]

Stock has a P stamp under the grip behind the trigger.
Not sure about the oprod cut out

Posted: 6/27/2018 3:42:23 PM EDT

[#6]

The arsenal standard method for tightening the rear sight (left to right) is to use a center punch on the side of the sight base on the right side just above the wide part of the sight ramp (midway from top to bottom).
Caution:
1) Punch with ramp in place.
2) Punch lightly and get slowly more aggressive. Many sight bases get cracked by being hit too hard.
3) IF you have other parts, try to find a combination that is what you want (before you crack the sight base).
4) With a caliper or micrometer, check the ramp to verify a uniform width. If not, stone (don't file) the sides to assure a smooth and accurate operation.

Don't crack the base (see #2 above)

Posted: 6/27/2018 9:47:46 PM EDT

[#7]

I believe thats a winchester upper handguard clip.

Posted: 6/27/2018 10:21:13 PM EDT

[#8]

Looks like the windage knob is a tad loose.

Should look more like this;

And here's a pic of the op rod cut;

An uncut rod will have a 90° bend where line has the circular cutout.

Btw, great looking rifle!

Posted: 6/28/2018 6:28:39 PM EDT

[#9]

I've done it once. You hit the sight base where the aperture edge corresponds. Three places. Then carefully do each one again until the aperture fits snug. It's then lapped. Per Kuhnhausen manual.

You do risk cracking through depending on how hard the base is. I've done it once and it worked out.

Posted: 6/28/2018 10:10:49 PM EDT

[#10]

Quoted:
I got a 1943 M1 yesterday.
While at the range today I noticed the rear sight appeture wiggles left / right. It also caused a couple of fliers way off from the rest of the groups.

A little research shows a few remedies, one being using a Center punch to peen the side to make it fit in there tighter. Does anyone have pics of the peening to show where to hit it ?

Or, do I just buy a replacement or two and hope one is nice and tight ?

https://www.AR15.Com/media/mediaFiles/27901/7E5C348B-7F2A-4D0B-B728-B91AB71EFA96-588588.JPG https://www.AR15.Com/media/mediaFiles/27901/F1BA121D-64EC-4456-BE5D-87AC4D25D88F-588589.JPG

View Quote

That lock-bar sight ain't locking.

Posted: 6/28/2018 10:51:11 PM EDT

[#11]

For what its worth ive got the lock bar and the screw on the left side as tight as it can go without getting so crazy and breaking something.

the aperture still wiggles and the sight base piece that surrounds it which has the two little ears sticking up wiggles a little also.

Posted: 6/30/2018 12:38:41 AM EDT

[#12]

Doing a little digging around online it looks like the rear sight spring cover can be the culprit for the wiggling aperture.

Should a guy try to replace that before peening any parts with a Center punch ?

Posted: 7/1/2018 7:35:41 PM EDT

[#13]

Quote History

Quoted:
Doing a little digging around online it looks like the rear sight spring cover can be the culprit for the wiggling aperture.

Should a guy try to replace that before peening any parts with a Center punch ?

View Quote

Yes. It may not fix it entirely, but it should tighten things up.

Posted: 7/3/2018 12:31:42 PM EDT

[#14]

Quote History

Quoted:
Yes. It may not fix it entirely, but it should tighten things up.

View Quote

The spring loaded sight cover will cure any up and down movement but not any left to right.

Posted: 7/4/2018 11:19:51 AM EDT

[#15]

Quote History

Quoted:
Looks like the windage knob is a tad loose.

Should look more like this;

https://www.AR15.Com/media/mediaFiles/648/20180627_200408-589509.jpg

And here's a pic of the op rod cut;

https://www.AR15.Com/media/mediaFiles/648/20180627_200438-589514.jpg

An uncut rod will have a 90° bend where line has the circular cutout.

Btw, great looking rifle!

View Quote

Finally took the rifle apart just now. It is an SA oprod, and it is uncut.

Posted: 7/4/2018 12:04:31 PM EDT

[#16]

I ordered a rear sight cover spring.
Tore the sights apart for a full cleaning. There was the expected amount of gunk and surface rust in there. Did a full cleaning and greasing of the parts.
Put in the replacement spring cover.

It seems to have tightened it up GREATLY. It takes actual force to make it wiggle at all. Before just your pinky could make it move both directions without any force applied.

I did notice that the sight apurture goes have a visible gap in it where it slides inside the base.
I should have ordered a new sight apurture as well but didn’t want to spend too much on parts.

I also replaced the oprod spring - the new one looks 1/4” or more longer than the original.

I’ll post a range report this afternoon !

Posted: 7/4/2018 3:23:22 PM EDT

[#17]

Currently at the range.
I’ve had 3-4 failures to feed.
Empty case fully ejected but the new round wasn’t picked up by the bolt.
I did a grease and oil job on the rifle while I had the stock off.
It did this 1-2 times before I put the new oprod spring in.
I’ve never had this issue with a Garand so any advice would be appreciated.

Edit - the gas plug was an 1/8th of a turn loose but I was out of ammo after I realized this and tightened it.

[ARCHIVED THREAD] - New to me M1 rear sight wiggles

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