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Posted: 9/21/2013 1:31:12 PM EDT
| Just got a Matech BUIS that was new in wrapper. As soon as I put it on my upper and tightened it down the head of the screw popped off. No excessive force was applied. I know that LWRC handles Matech spare parts and distribution. But I am not interested in paying $19 in shipping for a $6 part. Anyone know of another source with more reasonable shipping? |
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That's a very commonly broken part, it's known to be the weak link of the sight. BAD makes an improved replacement for the screw and clamp, and it's $19 with free shipping:
http://shop.battlearmsdevelopment.com/BRACKET-SCREW-for-MATECH-BUIS-AR15-M4-M16-FREE-SHIPPING-BAD-BSM.htm Replacing the broken screw with another factory screw may get you the same results as your original one, I'd recommend the BAD upgrade. The original screw has an over sized Allen head. This aspect, in conjunction with the small diameter and relatively weak screw, it tends to over torque, which resulting the recoil screw snapping in two. We have strengthened the mounting screw, in our tests, the factory screw snapped at 30 inch-pound, the screw we selected, a Grade 8 plus, broke between 45 and 52 inch-pound. The Allen head on our screw is smaller to reduce the likelihood of over torque. In addition, the mounting bracket itself has been redesigned. The bracket is counter bored to reduce the protrusion of the screw. The section that interfaces with the sight is twice as thick as the factory clamp (1.25mm vs. 2.60mm). |
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