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View Full Version : MaTech BUIS problem: deploying too easily (problem solved!...for now)


Fobjoe
03-03-2010, 1:10 AM
I've been using a MaTech 600M BUIS on my AR-15 and last range session I noticed that it would always deploy after being subjected to the mild recoil from the bench. I would look down after taking a shot and notice that it was only being stopped by my ACOG. I heard that the locking mechanism tends to wear over time and usage but I would expect it to last longer. Is there a way to fix this short of purchasing a new one? It's not really a huge problem since it's still out of the way but I don't like the idea of it touching my ACOG. Thanks for your replies.


EDIT: less than an hour after Joefrank64k's advice, I came up with this temporary fix. I took a replacement eraser for a mechanical pencil and used a knife to cut it down to size. I placed it on the right side of the pin between the mount. I wish the eraser were black for aesthetic reasons, but I know it's not going anywhere.

(windage will be limited in the meantime but rubber will give at least a couple clicks)

aplinker
03-03-2010, 1:11 AM
Failure mechanism #1. Call LWRC and see what they'll do for you. Otherwise you'll need to get a new one.

It's just a little nub that keeps it from deploying. It gets worn down as you deploy it repeatedly. Eventually it stops keeping it folded down.

joefrank64k
03-03-2010, 7:06 AM
I bought a Matech from another CalGunner that he advertised as having that same problem. I was able to fix it pretty easily. YMMV of course.

The issue with mine was that the pivot pin for the flip-up sight had "walked" out of position and was allowing the flip-up to deflect off of the detent and deploy.

I was able to use a thin putty knife to push the pivot pin back into position, and the sight works great!

I don't have photos since I'm away from the house right now, but if this is what's causing your problem, then you *should* be able to see what I'm talking about.

Fobjoe
03-03-2010, 8:41 AM
Well I'll be damned! Thank you, Sir! looks like that was the problem. I noticed that even with use the pin starts to walk out. Time to find a creative way to keep it in place!


I bought a Matech from another CalGunner that he advertised as having that same problem. I was able to fix it pretty easily. YMMV of course.

The issue with mine was that the pivot pin for the flip-up sight had "walked" out of position and was allowing the flip-up to deflect off of the detent and deploy.

I was able to use a thin putty knife to push the pivot pin back into position, and the sight works great!

I don't have photos since I'm away from the house right now, but if this is what's causing your problem, then you *should* be able to see what I'm talking about.

joefrank64k
03-03-2010, 8:55 AM
Well I'll be damned! Thank you, Sir! looks like that was the problem. I noticed that even with use the pin starts to walk out. Time to find a creative way to keep it in place!

Glad it worked out for you! I'm working on a solution as well...let me know if you come up with something that works, and I'll do the same!

Fobjoe
03-03-2010, 9:02 AM
Glad it worked out for you! I'm working on a solution as well...let me know if you come up with something that works, and I'll do the same!

less than an hour later I came up with this temporary fix. I took a replacement eraser for a mechanical pencil and used a knife to cut it down to size. I placed it on the right side of the pin between the mount. I wish the eraser were black for aesthetic reasons, but I know it's not going anywhere.

(windage will be limited in the meantime but rubber will give at least a couple clicks)

:D

joefrank64k
03-03-2010, 9:07 AM
less than an hour later I came up with this temporary fix. I took a replacement eraser for a mechanical pencil and used a knife to cut it down to size. I placed it on the right side of the pin between the mount. I wish the eraser were black for aesthetic reasons, but I know it's not going anywhere.

(windage will be limited in the meantime but rubber will give at least a couple clicks)

:D

Great idea! Thanks! A cheap fix for a sight that only cost me $18!!! And now I now what to do when my other (new) Matech starts to act up...

Gotta love CalGuns! :D

GTXR390
03-03-2010, 9:30 AM
Great idea! Thanks! A cheap fix for a sight that only cost me $18!!! And now I now what to do when my other (new) Matech starts to act up...

Gotta love CalGuns! :D

buy a Troy flip BUIS instead. this thing is solid.

joefrank64k
03-03-2010, 9:59 AM
buy a Troy flip BUIS instead. this thing is solid.

Yes, they are VERY nice...but my brand new Matech cost $45 and my used one cost $18 (both amounts included shipping), and they usually take A LOT of abuse before the problem surfaces...

Compare that to, what, $100 for the Troy? And the only issue is that the Matechs develop "premature deployment" :D

So for $63 I've got 2 BUIS that work great...I've got to pinch pennies where I can since I've been blowing so much $$$ on guns and ammo! :D

GTXR390
03-03-2010, 10:17 AM
Yes, they are VERY nice...but my brand new Matech cost $45 and my used one cost $18 (both amounts included shipping), and they usually take A LOT of abuse before the problem surfaces...

Compare that to, what, $100 for the Troy? And the only issue is that the Matechs develop "premature deployment" :D

So for $63 I've got 2 BUIS that work great...I've got to pinch pennies where I can since I've been blowing so much $$$ on guns and ammo! :D

good point.

was looking at the Matech, but it's sits higher when folded, right? i thought they were more expensive. ~$90??? but coo that you were able to find it for $18

i just went Troy, cuz it's solid...good reviews, and i won't have to replace it anytime soon ;)

joefrank64k
03-03-2010, 10:30 AM
good point.

was looking at the Matech, but it's sits higher when folded, right? i thought they were more expensive. ~$90??? but coo that you were able to find it for $18

i just went Troy, cuz it's solid...good reviews, and i won't have to replace it anytime soon ;)

That Troy is a nice sight! Very well made...

The retail on the Matechs is around $120...but they are often on sale for about $80 from "legit" retailers and you can find the them on the boards every so often, and they usually go for between $45 and $60 new...I think that people get "overruns" from the military (since the Matech is USGI issue) and sell them cheap.

Again, the Troy is a REALLY nice BUIS! Like you said, it's going to last, that's for sure!