MCX Top Rail Flexing

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[ARCHIVED THREAD] - MCX Top Rail Flexing

Posted: 5/15/2019 9:26:42 AM EDT

I have a keymod legacy MCX and I have a MAWL mounted on the rail in front. Recently I noticed that the rail has about 2-3 MOA of “flex” in it. If I am shooting off of a barricade and support the rifle near the mag well, the laser is aligned with the scope. However, if I support the rifle with my hand and hold it close to the end of the hand guard, the laser is about 2-3 MOA high and I can see the laser move in the scope.

Has anyone else experienced this flex, any solutions to fix it?

Posted: 5/15/2019 9:31:44 AM EDT

[#1]

You're mounted on the rail/handguard? Or you're mounted on the top rail of the MCX upper/chassis?

Posted: 5/15/2019 9:46:52 AM EDT

[#2]

Quote History

Quoted:
You're mounted on the rail/handguard? Or you're mounted on the top rail of the MCX upper/chassis?

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I have tried both, mounting the MAWL on the top rail that is part of the upper (i.e. doesn’t come off if the hand guard is removed) and on the hand guard itself. I didn’t notice any real difference in the amount of flex and prefer the laser to be mounted further forward for hand placement. It isn’t enough flex to see with the naked but, but on steel at 300 is where I noticed the flex.

Posted: 5/15/2019 12:21:25 PM EDT

[#3]

Quote History

Quoted:

I have tried both, mounting the MAWL on the top rail that is part of the upper (i.e. doesn’t come off if the hand guard is removed) and on the hand guard itself. I didn’t notice any real difference in the amount of flex and prefer the laser to be mounted further forward for hand placement. It isn’t enough flex to see with the naked but, but on steel at 300 is where I noticed the flex.

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Pretty sure 300 yards is way outside what is considered the effective range for laser sighting. I'd say 2-3 MOA is expected at that distance. Is there a reason you need the laser to shoot that far?

Posted: 5/15/2019 12:45:52 PM EDT

[#4]

Are you using a barricade or hand stop to brace, or are you just resting the forearm on the barricade?

Pretty much no matter what rail you have, you are strong enough to induce some flex into it if you are bracing it from the front. Since your optic is mounted so far back (relatively), you will notice less deflection than your laser.

Posted: 5/15/2019 1:07:31 PM EDT

[#5]

One of the reasons, even on ARs, you see some people mount their PEQ or DBAL at the back of the rail is that any one of them will have some deflection, and mounting over the barrel nut will have the least.

Have you looked into getting a night vision compatible optic, like an Aimpoint T2 or Eotech EXPS3 and using that for your 300 meter shots?

Posted: 5/15/2019 5:18:54 PM EDT

[#6]

Quote History

Quoted:
I have tried both, mounting the MAWL on the top rail that is part of the upper (i.e. doesn’t come off if the hand guard is removed) and on the hand guard itself. I didn’t notice any real difference in the amount of flex and prefer the laser to be mounted further forward for hand placement. It isn’t enough flex to see with the naked but, but on steel at 300 is where I noticed the flex.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
You're mounted on the rail/handguard? Or you're mounted on the top rail of the MCX upper/chassis?

I have tried both, mounting the MAWL on the top rail that is part of the upper (i.e. doesn’t come off if the hand guard is removed) and on the hand guard itself. I didn’t notice any real difference in the amount of flex and prefer the laser to be mounted further forward for hand placement. It isn’t enough flex to see with the naked but, but on steel at 300 is where I noticed the flex.

Legacy MCX hand guards are known to have deviation from zero, sometimes (they werent/arent guaranteed RTZ, like the Virtus - but it truly differs from rail-to-rail).

You shouldn't be seeing any "flex" from the chassis/upper itself.

[ARCHIVED THREAD] - MCX Top Rail Flexing

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