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10/20/2017 1:01:18 AM
9/22/2017 12:11:25 AM
Posted: 8/3/2005 2:41:56 AM EDT
[Last Edit: 8/3/2005 2:44:58 AM EDT by 3ACR_Scout]
Hey all,

I bought a lightly-used #40L and mounted it on my M4 a couple weeks ago (we have the Army-issue BUIS on order but haven't received any yet). I took it out today to zero, qualify, and shoot familiarization at the range and ran into a couple problems.

The first issue is that I had to max the adjustment all the way to the right to bring my shot groups on target - I literally hit the last click on the knob. I've never had to adjust my rear sight that far to one side with any other iron sights. Could this be an issue with the sight mounting crooked or something? If it was twisted to the right somehow, I could see it needing this kind of adjustment. I'll probably go back and try my LMT BUIS that I don't really like, just to make sure it's not me.

The bigger problem - after qualifying (using my M68 sight), I noticed that the #40L was loose, and I tightened it up again (but didn't have any loctite with me). After qualifying, we all spent a bit of time doing familiarization fire with both pistols and M4s. After some sustained auto fire (about 5 or 6 magazines - we were using up some old ammo), apparently the bolt and clamp on the #40L came completely loose and fell out (the parts disappeared into the moon dust out at our range). I guess I should have noticed it rattling, but I didn't realize it until the BUIS fell off my weapon when I set it down to police up my brass.

Anyone run into this problem? I'm wondering if the mounting system just isn't designed for this kind of abuse (sustained fire) or if I just didn't use enough loctite. So now I have a BUIS that I can't mount (I'll have to write to A.R.M.S. for replacement parts I guess). I think a lever or other type of permanently attached locking system would be a lot better than the bolt and clamp that can fall right off the sight. I really like the design of the sight itself - the fixed LMT sight I have just gets in the way of the red dot - but I'd hate to have this happen while I'm outside the wire.

Thanks in advance for your comments / advice,

Dave
Link Posted: 8/3/2005 3:48:23 AM EDT
i have read of issues with the sight loosening itself and bad sights that were causing the max windage.
maybe try and search it?


i personally have yet to encounter any of these problems though and usually put a dab of blue loctite on the screws.
Link Posted: 8/3/2005 4:36:09 AM EDT
I have the same promlem with a standard 40 and called ARMS about it. The tech.(Josh) told me that on some of the early models ( I'm assuming all variations) they made the fit for the receiver a little over size to accomidate for different manuf. tollerances and if you get a spec. or smaller receiver this issue could happen. Give them a call and they will probably replace it like they are doing mine. 508-584-7816.
Link Posted: 8/3/2005 4:54:22 AM EDT

Originally Posted By LOPREFIN:
I have the same promlem with a standard 40 and called ARMS about it. The tech.(Josh) told me that on some of the early models ( I'm assuming all variations) they made the fit for the receiver a little over size to accomidate for different manuf. tollerances and if you get a spec. or smaller receiver this issue could happen. Give them a call and they will probably replace it like they are doing mine. 508-584-7816.



Thanks for the advice - unfortunately I'm in Iraq and would prefer not to have to call them from over here. I tried using their "Contact Us" feature on their website, but the "Submit" button doesn't seem to actually work... Anyone have an email address for them? Thanks again,

Dave
Link Posted: 8/3/2005 8:44:49 AM EDT
Try emailing techsupport@armsmounts.com for replacement parts.

I haven't had any issues with my #40l loosening up but I tightened the hell out of it with the supplied loctite when I installed it. This is after a whole lot of rapid fire strings including full-auto dumps with Cmags etc.

The clamp is plenty strong too....as exhibited by a gentleman on this board who's receiver blew apart and the #40A2 he had on there bent a bit but he claimed that it held the rear of the receiver together. (can't find the post right now but it had pics).

The Army issued BUIS has a "dot" of red loctite on the attaching bolt to keep this from happening as well.

GIve them a call or send them an email and I'm sure they'll fix you up.


Link Posted: 8/3/2005 9:34:42 AM EDT
Link Posted: 8/3/2005 10:01:20 AM EDT
I had the exact same problem that you described. First thing that I did was send my upper back to the manufacturer as I questioned the front sight being canted off to the side. The manufacturer replaced the complete upper (new barrel & receiver). Next, I contacted ARMS and spoke with Josh and he sent me a replacement BUIS 40. After these two fixes, I can finally sight it in without having to adjust all the way over. I still had to adjust the windage a few clicks but now it will sight in without hitting the side of the sight protector. I understand that trying to switch out the upper in Iraq may not be as easy as being in the states, but I would definitely go and get the sight replaced as ARMS has excellent customer service; I'm sure that they would do whatever it takes to get you a replacement sight since you are in the military serving oversees.

As far as the sight losing up, I applied loctite blue and no more problems.

Good luck and keep your head down!
Link Posted: 8/4/2005 9:36:40 AM EDT
I've got a 40L and a 40 that I'm sending back this weekend to get fixed up...
Link Posted: 8/4/2005 11:55:21 AM EDT
[Last Edit: 8/4/2005 11:55:48 AM EDT by VTDefender]
www.ar15.com/forums/topic.html?b=3&f=14&t=238612

Here's the link to the pictures I was looking for.
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