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Posted: 1/11/2004 10:45:12 AM EDT
| I know this is a real newby question, but in the AR world, I'm a real newby. I've just built my first AR, using gunshow components. I've got an Olympic Arms M4-A3 upper with a detachable carry handle. I just got a carry handle mounting rail from Model 1 sales. My older Tasco PDP2 red-dot won't fit well on the rail. It seems that the rail is thicker than the sight was designed for. My question is this. What are the differences between the available mounting rails, both AR "picatinny" type and commercial "Weaver" type rails? If I order a scope, how will I know what rail it is made for? |
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The standards for the Mil-Spec 1913 rail, developed at Picatinny Arsenal and commonly called a Picatinny rail, are based on the Weaver rail. Weaver rails have a specified width and angle to the rails, but there were no specifications for where the cross-slots had to be, how wide they could be, how deep they could be, how many slots per inch, spacing, and so forth. The 1913 specs standardized all that, so that devices could be moved from one gun to another. The problem you're having is almost certainly due to out-of-spec parts. Many of the cheap Chinese-made rails are made from extrusions and are not perfectly straight, and aren't machined straight. They may resemble an ARMS product at first glance, but the [b]details[/b] are very different. Some ring designs will allow a greater variation in rail width, and others don't. It sounds like yours are the latter. You're either going to need to return your rail and find one that will work with your existing rings, or get new rings that will work with your rail. -Troy |
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Yes, the caheaper rails are usually poorly machined and way out of spec. Your best bet is to mount directly to the receiver. If it is too low for you, I would reccomend getting a riser and a back-up sight from one of these companies: [url=http://www.armsmounts.com]ARMS[/url] or [url=http://gggaz.com]GG&G[/url] Look around this site (the Industry section and the Equipment Exchange) for some good deals on these items. They probably cost more than what you wanted to spend, but they are really the only options for good, in-spec accessories. As Troy has said before, buy cheap and buy twice. |
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