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  #1  
Old 05-10-2017, 12:11 AM
VonZipper VonZipper is offline
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Is the Top Rail on the M&P Sport mil spec

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Old 05-10-2017, 08:01 AM
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Yes... it is a picatinny rail, also referred to as MIL-STD-1913.
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Old 05-11-2017, 08:07 PM
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So if it is military spec why is a A2 site not tighten up on it?

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Old 05-11-2017, 08:38 PM
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Maybe the sight is the issue. I have several rings that won't clamp down firmly on the rails of several firearms. Odd are that all the random firearms AREN'T the problem as other rings are fine on them.
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Old 05-11-2017, 09:06 PM
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Quote:
Originally Posted by VonZipper View Post
So if it is military spec why is a A2 site not tighten up on it?
This doesn't make any sense. An A2 sight is pinned and is part of the gas block. Can you post a pic?
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Old 05-11-2017, 09:08 PM
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Wait, are you talking about a rear sight? Maybe an integrated handle like the A3?
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Old 05-11-2017, 09:58 PM
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Quote:
Originally Posted by VonZipper View Post
So if it is military spec why is a A2 site not tighten up on it?

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As mentioned by Rastoff, an A2 front sight is pinned in place on the barrel and an A2 rear sight would be an integrated carry handle.

Please post picture and the brand and part number of the sight you are trying to install. Chances are that the sight is the issue, not the rail on your Sport.
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Old 05-12-2017, 07:37 AM
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If whatever it is you're trying to mount on the upper receiver rail doesn't properly secure... the rail is fine but the accessory is-

A. Defective.
B. Wrong size.
A. Operator error installation.
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Old 05-12-2017, 08:57 AM
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Quote:
Originally Posted by ChattanoogaPhil View Post
If whatever it is you're trying to mount on the upper receiver rail doesn't properly secure... the rail is fine but the accessory is-

A. Defective.
B. Wrong size.
A. Operator error installation.
I'm guessing A (which should be C ), operator error.

I was test fitting an ACOG I just bought used the other day and had it fit perfectly with the QD mount on my one rifle, then I switched it over to another rifle and the QD mount was too tight with the lever. Now how can that be with both being milspec upper receivers......had to be operator error like I didn't have it seated properly or something.
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Last edited by ChattanoogaPhil; 05-12-2017 at 09:06 AM. Reason: CS
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Old 05-12-2017, 09:14 AM
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Quote:
Originally Posted by Kadonny View Post
I'm guessing A (which should be C ), operator error.

I was test fitting an ACOG I just bought used the other day and had it fit perfectly with the QD mount on my one rifle, then I switched it over to another rifle and the QD mount was too tight with the lever. Now how can that be with both being milspec upper receivers......had to be operator error like I didn't have it seated properly or something.
Right.

Different hard coat anodizing applications, some include teflon finishes or completely different finishes like Cerakote can explain slight differences. But if the accessory simply won't secure like the OP suggests then A B or C is my best guess.
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Old 05-12-2017, 10:11 AM
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Just a different finish won't account for it. I've never seen a Picatinny attachment that had less than .125" adjustment. Most finishes are .010" thick or less. It's not the finish.
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Old 08-05-2017, 11:35 PM
VonZipper VonZipper is offline
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I stand corrected. I am referring to the rear handle. I got another handle and all fits fine. Thank you all.
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