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M&P adjustable rear sight pivot pin sliding out?


MilkMyDuds

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Hello,
I have recently ordered the adjustable rear sight for my MP9. The invoice number is 056509
034-004 - Sight/S&W/RearAdj/M&P/Blk/.125N/Requires .285 Tall Front/Tools Included
After a couple range trips, I just noticed today while cleaning the gun that the pivot pin on the rear adjustable sight slid out about 3/8 inch. I pressed down the sight and used a punch to pushed the pin back in. I am concerned though because this is only the 2nd trip to the range. If I had not paid attention, I am afraid the pin may go out and get lost.
Will sight still hold zero after the pivot pin's movement? Is this normal? Could this be caused by too much force of slide on frame? Maybe I need to switch to a stronger recoil spring (have been using 13# and just switched to 11# this week)?

Thanks.

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The pin does not need to be shortened to stay in recess on both ends. It is shorter than the length of the pin hole. However, I don't know how to crimp the 2 opening of the pin hole... Solder or glue? Can you pleas elaborate?

Sent from my SM-N910C using Tapatalk

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Steve, not sure how to do that, but I will google a bit to find out.

I went to the range today and shot only 50 rounds. The pin slid out again, from the left side where the hold opening is bigger. I took some closer look at the Dawson adjustable sight. In my opinion, the pivot pin design does not seem very solid. Some minor vibration could cause a few things to happen:

1. The pivot pin could slide out. What's going to happen when it is totally out? I don't know and I did not test as I don't want to re-zero only 1 week from the world shoot (maybe the fact it slid out already means the sight is no longer zeroed?). Maybe Dawson could clarify. I suspect the sight would be useless.

2. The rear blade could easily move up and down into a tilt with just minor pressure applied from left to right on the blade, e.g. with the tip of my finger slightly pressing it side way from left to right. This is not engaging anything with the spring system that holds the blade in place, as you can see in the picture it is just the top part of the blade moving, while the bottom part is where the spring system controls. It's interesting if you press slightly from right to left the blade holds steady. I am not sure how much impact this has on the POA, especially when shooting fast. I have noticed recently I have been shooting low while shooting fast. Does this have anything to do with it? Again, I don't fully understand why Dawson designed the rear blade in 2 parts with the top part seemingly to move freely (with a pin secured but the pin could move too when there is slight pressure).

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Take a small punch and strike the edge of the hole so it bends a little of the metal over the hole. This will prevent the pin from coming out. Do this on both sides of the sight.

I'm sorry but I don't know any better way to explain it.

I have the same sight on a 9mm 1911 and it seems to work ok.

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Take a small punch and strike the edge of the hole so it bends a little of the metal over the hole. This will prevent the pin from coming out. Do this on both sides of the sight.

I'm sorry but I don't know any better way to explain it.

I have the same sight on a 9mm 1911 and it seems to work ok.

Tried this last night but it was not easy. I dinged around the hole but I was not able to form any crimp. The sight is really hard metal, plus it is still installed on my slide and I was afraid to damage the dovetail. I'd hate having to remove the sight as loctite has been used per Dawson' instructions.

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If you use a small, flat ended round punch (just slightly bigger than the hole), brace the other side of the sight well on something rigid, center the punch on the hole and hit it briskly with a hammer it will end up with the appearance of a crimped primer. This will keep the pin from coming out.

Or, you could clean it well with alcohol and epoxy it in from both sides.

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Thanks Steve.

I did the punch fix, but I don't have a proper size so I had to use a small one to hit the edges of the hole. It looks butt ugly now. I tried it at the range today, and no sliding out after 300 rounds.

I don't know how long this fix could hold though. Hope Dawson has a more permanent fix for this.

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