Bushmaster A2 sight.....?

[Tony Mig]

I've got a new Bushmaster XM15 E2S, I've had it to the range and shot it for the third time today, and noticed something odd about the rear sight assembly.
The rear sight assembly is a sepperate unit of the top handle, and I never noticed this before, but it seems to move slightly. I cocks to the left (counter clockwise) and throws it slightly out of line with the channel in the handle, not by much, and the sights still seem to be dead on, but the fact that the entire assembly can more gives me concern.
I inspected the assembly, and looked over the spec sheet drawling and parts breakdown to insure nothing was missing, and it doesn't appear to be any lost screws or pins.
Is it normal for these rear sights to do this.....?
Is this a Bushmaster thing, or are all A2 type AR rifles like this.....?
If this is not right, is there an easy fix, or am I looking at sending this rifle back to Bushmaster.......?

I appreciate any help or advice you other AR shooters can provide....thanks

 

[Quintin Likely]

That's normal, just the nature of the beast. Focus on the front sight and don't worry about it. Some competition sights use two (or more) pins that are installed vertically through the sight base to ward off bad karma and that side play, but otherwise, don't worry about it. I forget the exact reason as to why it's cocked to the side a little, though. Something about the tension applied on the windage end of the sight I think.

 

[Rexrider]

Here is a "second" on your sight being normal. All A2 sights are made this way (Sights on an A3 carry handle do the same thing as well). The amount of play may vary from rifle to rifle but there will always be some amont of movement.

As long as the sight returns to the same position under spring tension you are good to go. If it just flops around then something did break.

Enjoy the rifle.

Cheers

 

[226]

My A2 attached to an A3 type detachable handle on my Colt 6920 does that. As long as it swings / has tension to the same side (looking from the rear, front right on mine) your zero should be fine.

 

[hksw]

There is an amount of space between the A2 rear sight assembly and the carry handle to allow for unhindered movement of the sight during adjustment.

There is a rear sight helical spring and ball bearing detent in a hole located in the left front of the rear sight base frame between it and the upper receiver handle. (The spring and ball are entirely contained and held in position between the sight base and handle as long as the sight is not raise out of its position.) It is difficult to see but if you hold the rifle up to a bright background or light you can see the ball. The purpose for this spring and ball bearing detent is to apply force to the left side of the handle causing the sight to rotate counterclockwise (viewed from the top) until the right side of the sight base butts up against the right side of the handle. By doing this, the sight is basically insured of providing a repeatable position for the rear sight after any adjustments are made and after recoil.

 

[Tony Mig]

I thank you good people for this information. It's just that I didn't notice this until today, and thought I might have lost a pin or screw.

My previous AR rifle was a Colt A1, and the sight was built into the handle, this A2 type sighting system is kinda new to me, so I can strike this off as a learning moment.....

A while back I owned an M1A, and had the sight adjustment screw fall out on me while shooting. I couldn't understand why I was hitting low, then that screw hit the shooting bench, and I stopped wondering. After that, I paid a little more attention to checking such things while cleaning.

Again I thank you all for helping me out on this one........

 

[Commissar Gribb]

welcome to the world of A2 sights! I think you'll like it better here

sure beats slow adjustments with a dummy bullet