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Posted: 2/25/2008 6:43:33 PM EDT
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Seems I have a flat learning curve when it comes to picatinny mil standard and weaver style rings. I do know that weaver rings will fit picatinny, but not the other, as the picatinny slot's are bigger. Who in the heck makes a scope ring for picatinny mil-spec that indexes to these rails, in ultra high configuration? I want the recoil lug to fit in my mil-spec upper, with very high dimensions to clear the front sight gas block. I am tired of messing around with weaver style rings to the point of frustration. Thanks in advance! |
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ARMS, LaRue, GG&G, NF Rings, Leupold MK4 rings, and so on will work for Picatinny. Weaver should work just fine. If we can be of help feel free to call. Mike @ CSGW www.csgunworks.com [email protected] Here’s some testimonials about CS GunWorks What do YOU have to say about CS GunWorks What Do You Think Of Cs Gunworks? |
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Picatinny is a spec, with dimensions and tolerances, while Weaver is a design concept, and there are nearly infinite variations on it. That said, in general, Weaver slots are narrower and spaced differently than the Picatinny spec. AFAIK, there's no spec for the gear that fits the Picatinny rail, only for the rail itself. That is, Armalite's recoil lug doesn't need to be the same dimension as LaRue's recoil lugs, and lots of gear doesn't even have a separate lug. Many rings use the cross-slot screw as a recoil lug, and will work on either type of mount. For instance, the Eotech comes with a cross-slot screw that fits both Picatinny and Weaver, and no separate recoil lug. This could theoretically be a problem, as recoil forces push against the rounded shank of the screw, but generally, it's not. Burris' XTR rings avoid this by machining a 90 degree wedge out of the cross-slot screw to butt up against the slot face. Some rings, like Armalite's, have a seperate recoil lug molded into the ring base, or as a separate piece, like the Warne Maxima. These are going to be a tighter fit, but will still have play, as they want them to fit mildly out of spec, dirty, or dinged rails. Some, like ARMS 38 rails, have a square shank on the cross-slot screw to keep the recoil forces square, but they're still a good bit smaller than the slot. With any style, the key is to push the ring(s) all the way forward so the recoil lug or cross-slot screw is against the front of the slot. Here are a few examples: ARMS 38 S-EX bottom, showing the square shanks on the cross-slot screws.  Armalite one-piece, showing the recoil lug. Their rings are similar, and the cross-slot screws don't take any recoil forces in this design.  Warne Maxima with separate recoil lug. This is loose in the ring until it's pushed against the front of the slot. 
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Not that I know of, because it wouldn't fit in a rail that was a little out of spec, and there are quite a few of those out there. The spec is 0.206 +0.008, so there's a little room to play, but it costs a more to hold that kind of tolerance, of course. I don't have the numbers in front of me, but I can post the Armalite recoil lug measurements later. You could ask LaRue what their ring recoil lug measurement is - they're pretty serious about the spec and return to zero. |
| So---If no one has a scope ring with recoil lug to for either Picatinny or Weaver, why bother with the differences in mounts? Now I'm really confused??heThanks! |
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I looked at my mount data archive, and the only ones close to the slot width are the Armalite gear, with recoil lugs of 0.20" for both the rings (which they don't make any more) and one-piece mounts. Armalite's next, at 0.185. I don't have any LaRue or KAC to measure. Most of the slots on the Weaver gear I have are in the 0.15" to 0.18" range. My older RRA scout rail has 0.200" slots (out of spec), so the Armalite gear would be a very tight fit on it. Most vendors don't bother with different gear for the two designs, and make sure it works with Picatinny and Weaver both. Some stuff, like the Armalite rings, wouldn't fit on Weaver gear, but most of it will. Since the recoil forces are all rearward, a solid mount just needs to butt the lug against the front of the slot. What it really boils down to: If it says Picatinny, it'll fit Picatinny, but may or may not fit Weaver. This is especially true of gear with 2 lugs or cross-slot screws, as Weaver spacing is variable, while Picatinny is spec'ed. If it says Weaver, it'll generally fit both Weaver and Picatinny. Eotech says this about their sights with the skinny 0.135" cross-slot screw, like the 552 (some others have ARMS mounts). 
and they spec them at 1 MOA repeatability, which is plenty for their intended usage. Zeiss, on the other hand, has both versions in their Z point sight, but spec them in metric, at 5mm (0.197") and 3.8mm (0.150"), but this increases manufacturing and stocking costs, and makes for more customer confusion. I'd guess the 0.200 range is as tight as you're going to get.
As you can see, it's a bit of a jungle out there. There are specs, but not everyone follows them, and tighter specs increase costs. |
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