Front sight post wobble

[Bullets & Bacon]

I was just able to go zero my rifle at 100yds and I had to move the front sight post up so far that it wobbles pretty bad. Im using a 16" bcm ar-15 with the front sight that comes with the rifle and this rear sight http://palmettostatearmory.com/index.php/ar-15-05/upper-parts/sights/palmetto-state-armory-mil-spec-carry-handle.html
any advice of how to fix this problem will be much appreciated.

[Redhat]

What is the rear elevation wheel set to?

[citizensoldier16]

Your FSB may not be the F marked type, in which case you would have to raise your front sight post more. When I switched from a carry handle to a flip-up rear sight, I had to install the taller front sight post.

This may not be your problem, but its good info to have. Best of luck.

[Iraqgunz]

If it's a BCM upper, then it's 99% going to be an "F" marked sight base.


Your FSB may not be the F marked type, in which case you would have to raise your front sight post more. When I switched from a carry handle to a flip-up rear sight, I had to install the taller front sight post.

This may not be your problem, but its good info to have. Best of luck.

[mpom]

Simple solution; get a set screw of same thread size and pitch as front sight post, thread in from above with socket wrench recess facing down towards barrel. Thread way down so post can be placed above. Once post is incorrect position, thread set screw up to lock post in place and remove play from post. You can try threading set screw from below as that avoids having to remove and replace post, but front sight towers often are not threaded all the way through.
Keep the Allen wrench in/near rifle so future front sight adjustments are possible.



Mark

[Bullets & Bacon]

What is the rear elevation wheel set to?

300/600

[Redhat]

300/600

Here is some good information that might help you out:

http://m4carbine.net/showthread.php?t=65679

Go to the bottom in post #2 for info on removable carry handle sights on the 16" carbine.

[brs243]

300/600

Are you at 300 or 600?

[FLHXSG]

a little blue loctite on post's thread after zero will do.

[jmart]

If none of these suggestions work, just order a taller front sight post from Bushmaster. They run .04" taller and cost ~ $5. There may a problem with your detachanble carry handle, but you'll need to weigh how much you're willing to get that sorted out vs just springing the $5 and solving the problem.

[citizensoldier16]

If it's a BCM upper, then it's 99% going to be an "F" marked sight base.

Good point. I must have glossed over that part.

[Bullets & Bacon]

I used the set screw solution and now there is no wobble.

And thankyou for all of the advice.