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joel1316
02-14-2006, 10:21 AM
Can I use Weaver scope rings on a Picatinny rail?

Thanks!

elmo
02-14-2006, 11:02 AM
yup!

pict. rail is mil spec, weaver isn't. weaver will fit on a pict rail

pict item won't fit on a weaver rail.

maxicon
02-14-2006, 11:38 AM
It's a bit more complex than that, and the answer is "it depends", but it's true that Weaver will usually fit on a Picatinny rail, particularly for rings. Mounts are trickier.

Weaver rail is a design, not a spec. Slot and crossbar dimensions and spacing vary a lot, even within Weaver's designs. In general, the slots and crossbars are narrower than the Picatinny spec, and the spacing is totally variable. Weaver bars fit in 1913 slots (loosely), but not all 1913 compatible bars fit in Weaver slots. Many manufacturers purposely make the crossbars small enough to work on either slot, like on the Eotech holosights.

Picatinny (real name - MIL-STD-1913) is a spec based on the Weaver design, with tolerances. Any true Picatinny spec gear will work with other true Picatinny spec gear, but not all makers hold to the spec, just like with Weaver. Most often, the spacing and/or slot width are different for out of spec gear. Even ARMS, who some credit with developing the Weaver design into the Picatinny style design that was turned into the MIL-STD-1913, makes non-Picatinny spec mounts.

The cases where Weaver style gear won't mount on a Picatinny spec mount usually involve gear with 2 fixed position crossbars. Since the spacing is not controlled in the Weaver design, you can have a case where one crossbar fits in a slot and the other doesn't.

The SU16A is a good example of this - no Picatinny spec gear with 2 fixed crossbars will work on an SU16A, because the SU16A spacing is too short. Also, the slots are narrower than the Picatinny spec, so on some gear, the crossbar is too fat to fit in the SU16A slot. They fixed this with the SU16B and beyond by making them Picatinny spec.

Some gas block rails are not Picatinny spec either - I have one on my JT varmint upper, and RRA sells a varmint upper with what appears to be the identical railed gas block that has the same problem (they call it a Weaver gas block). I have a YHM front flip site with a crossbar that meets the Picatinny spec, and is too wide to fit on either of those railed gasblocks (or the SU16A rail).

This is probably more than you wanted to know, but that's how it works, in a nutshell.

max

joel1316
02-14-2006, 11:51 AM
Maxicon - thanks for the nutshell :)
Midway is going to carry some "picatinny" scope rings soon, maybe I'll just wait for those....

ohsmily
02-14-2006, 11:57 AM
Maxicon - thanks for the nutshell :)
Midway is going to carry some "picantiny" scope rings soon, maybe I'll just wait for those....

Maxicon just gave you a BEAUTIFUL rundown of weaver and MIL-STD-1913 (Picatinny) and then you just go and BUTCHER it with "picantiny". Say it "pick - a - tin - ee" and then spell it "picatinny".

joel1316
02-14-2006, 1:13 PM
Picatinny....

Thanks.... Still trying to get over some jet lag.....

ohsmily
02-14-2006, 2:40 PM
Picatinny....

Thanks.... Still trying to get over some jet lag.....
;)

........................

maxicon
02-14-2006, 6:04 PM
Midway is going to carry some "picatinny" scope rings soon, maybe I'll just wait for those....

I've found it doesn't make a lot of difference with inexpensive to mid-range rings, since you can adjust them back and forth to make up for any variations in spacing.

A lot depends on what you'll be shooting and mounting. The recoil of most .223s isn't enough to beat up good rings, but you still don't want them shifting in the slot. Heavy-duty rings tend to be heavy-weight, too, and that's a tradeoff as well.

Most less expensive rings, like Weavers, have a round crossbar (usually the screw), though some Weavers have squared screws. Better rings, like mid-range Leupolds, will often have a rectangular or square crossbar that's part of the tightening screw, which gives a better fit when it's butted up against the front of the groove, but it's not a tight fit in the groove.

Some heavy-duty rings, like some of Armalite's, have a fixed recoil lug that extends down into the groove and takes most of the recoil load, as well as a screw for tightening the mount down that extends partly into another groove, but doesn't take any load. This lug is a tight fit in a Picatinny spec groove and won't fit most Weaver grooves.

The Leupolds I've used (mostly QRW - my favorite - and PRW, not the high-end stuff) work with Picatinny and Weaver mounts, and are good quality without being dramatically expensive or heavy, while the Armalites need a full-width Picatinny spec groove and correct groove-to-groove spacing in order to fit.

Because there are so many variations in mounts, scopes, and rings, I've found it's good to post what you want to mount and what you want to mount it on, and see if anyone's got any specific suggestions.

I've bought lots of stuff that I thought would fill the bill, only to find there was some quirky little thing that kept it from all working together.

max

joel1316
02-15-2006, 5:50 AM
Once again Maxicon, thanks for the helpful information. Looks like I'll have a little bit of homwork to do.