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6/2/2020 2:34:59 PM
Posted: 12/28/2002 6:25:07 AM EDT
I have recently purchased a ARMS #40. I also have a BM flattop upper which I recently discovered is not milspec.  When trying to zero the ARMS I have to screw the front sight almost all the way out to get close to zero. I called ARMS and they offered a $180.00 solution.  Are there any other less expensive solutions out there to this problem?

Link Posted: 12/28/2002 6:26:56 AM EDT
You can get a longer front sight post...they're available, not sure exactly where though.  That's the quick and easy fix...not that $180 bs.
Link Posted: 12/28/2002 6:31:29 AM EDT
That would be a great solution. Anybody know where I can get one?
Link Posted: 12/28/2002 7:11:58 AM EDT
I just asked Pete in NH this same question regarding an RRA flattop and he told me that I would need a taller front sight post.

Here's his e-mail verbatim:

As with Bushmaster , Armalite and RRA You would have to add a taller front sight post
you need 30-40 thousands . The only one that you do not have to do that is with a Colt M-4 Barrel that has a   F   Stamped on left side of front sight housing  Colt makes
a special Taller front sight housing for FT Uppers  its about 40 thousands taller.

I have taller front sight posts at $8.95


His Contact Info:

Pete of Legal Transfers in NH
Po Box 172
Plaistow NH 03865


Link Posted: 12/28/2002 9:23:40 AM EDT

Thanks for the info.  I contacted Pete and he also recommended Ken Elmore at SA warehouse.  Does anybody know how to get in touch with him.
Link Posted: 12/28/2002 10:26:10 AM EDT

Why is it that Pete recommended another person rather than selling you the front sight post himself?  I'm not sure I understand.

Link Posted: 12/28/2002 11:24:04 AM EDT
[Last Edit: 12/28/2002 11:24:55 AM EDT by NYPatriot]
I just E-mailed Bushmaster about the BUIS compatibility issue, and I will post their response when I receive it.
Link Posted: 12/28/2002 1:54:30 PM EDT

He was just providing another option. He has a 60 thousands taller front sight for $8.95. SA warehouse has a front sight which is 40 thousands taller for about $15.00.    

Link Posted: 1/1/2003 8:09:32 PM EDT
Bushmaster's reply to the BUIS compatibility issue...

When Colt came out with the A3 design with the detachable carry handle they made the front and rear sights .040" higher than the sights used on A1 and A2 rifles. The front sight forging is the same but the front sight post when set for mechanical zero is even with the top of the sight ears instead of below them as the plane for the sight post is milled higher. You will notice on 20" A3 barrels there are two raised bands on the barrel under the handguards. This designates that the barrel has the front sight base with the front sight that is milled high for the front sight post. Colt parts lists have a different part number for the higher front sight base barrels and sight bases for A3 and M4 barrels. 

        We decided when we began to build the A3 models with detachable carry handles that we would keep the sight heights the same for all models. Our A3 handle, Flat-top Rear Sight and Rear Flip Up Sight has the same rear sight aperture height as on the A1 and A2 receivers so that all barrels with standard height front sight bases will interchange. The Mark Brown Flat Top Mount also uses this same rear sight height.

        The A.R.M.S. Swan Sleeve and # 40 Flip Up Rear Sights have the higher rear sight aperture height. When used with standard height front sight bases the front sight post must be turned out to the .040" higher position where it is even with the top of the sight base ears for mechanical zero.

        We now carry a .040" taller front sight post, part number 9349056-M for $4.95, to correct this difference.

        The taller front sight post should not stick up any further above the ears than the sight posts used on the Colt barrels.

        Thank you.
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