Weaver ring fit a Picatinny rail?
Will Weaver rings fit a Picatinny rail?
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Weaver is app. 025 smaller. Because of this will fit, but not vise versa. Because of the "slop", might cause problems in heavy recoiling firearms? 0 -
quote:Originally posted by 5mmgunguy
Will Weaver rings fit a Picatinny rail?
Yes, they should fit.
Picatinny (aka 1913 rail) is a very specific military spec with .206" wide grooves with a regular center-to-center width of .394" between the grooves. Weaver has a spec of .180" grooves, with groove-to-groove distances potentially varying depending on the nature of the mount.
Weaver accessories should all fit onto Picatinny rails (and I've done this), where as the converse isn't true. IE, true milspec Picatinny accessories might not fit onto nominal Weaver rails (but they still might).
What about the 0.026" extra "slop", you ask? In theory, that could allow undersized Weaver accessories about 0.026" back and forth "play" under recoil which could add to inaccuracy, and beat up the mounts.
In practice empirically, people put Weaver accessories onto Picatinny rails all the time, and most don't run into any problems. The fact is, there is supposed to be some play there. . .ie its not a "slip fit" where the bases just barely fit into the grooves, or you have to tap them into place!
If you tighten the rings down properly (not TOO tight!), they shouldn't move under recoil. Also, because of inertia, recoil tends to make scopes/rings jump FORWARD on the rail. So if you move the mounts as far forwards as possible on the base before tightening down, you'll reduce the possibility for movement.0 -
I do this all the time on 5.56 and 6mmx45 ARs without loosening or application of Loctite.
As an aside on loosening of mounts history, I had a lot of loosening of Redfield Jr windage /retaining screws on a lightweight 30-06 rifle in the service.
It was surprising to see that Redfield on an Elephant rifle cal commercial Mauser at the range yesterday. He was practicing for a Cape Buffalo hunt.
Loctite or no it's a weak mount.0 -
I had problems with the cross bolts, weaver is round the other is square profile. The Weaver did not fit the Picatinny rail slots. Some careful work with a file got them installed. 0 -
beantownshootah. Question. You say the Picatinny has a .206 groove width and Weaver has a .180 inch groove width. Isn't the center to center width between the grooves and angle of the groove the critical elements? As long as the rings and the bases are designed to mate in width and groove angle are they not the most important? How does the .026 difference make for back and forth play? 0 -
quote:Originally posted by 5mmgunguy
beantownshootah. Question. You say the Picatinny has a .206 groove width and Weaver has a .180 inch groove width.[
Those are the published specs.
As I mentioned above, in reality, not every piece of equipment with the words "Weaver" or "Picatinny" on them actually MEET those specs. . .so the actual sizes of any given piece may not actually match the above. . .even though they're "supposed" to. IE, there are so called "Weaver" accessories that are actually built to Picatinny specs, etc.
quote: Isn't the center to center width between the grooves and angle of the groove the critical elements? As long as the rings and the bases are designed to mate in width and groove angle are they not the most important? How does the .026 difference make for back and forth play?
Well, I don't think it should be too conceptually hard to understand why if you were to put a .180" wide mounting bolt/rod into a .206" wide slot you could POTENTIALLY get up to .026" back-and-forth play where the mount can "wiggle" back and forth in the slot.
Of course to have any play assumes that the mount is otherwise free to move back and forth. In other words, it hasn't been tightened down, or its worked itself loose! (Or that there isn't some other geometric fit between the mount and slot preventing movement, like a round bottomed bolt sitting in a round-bottomed slot).
If, as you say, we assume that the mount otherwise fits on the rail, and its screwed down tightly enough to resist the forces generated by recoil, its not going to move, regardless of any difference between mount and slot sizes.
That's the reality the majority of the time, and discussion can basically end there.
In short, the .026" POTENTIAL movement is really only an issue if the mount itself is loose (ie it loosened under recoil). Even then, as above, the mount is probably only going to move one direction. . .towards the muzzle, where it will then hit the front of the mounting slot and stop moving. Assuming the mount was centered in the slot to begin with, its only going to move half of the available "play" or 0.013".
Edit (responding to below):
Heh. .Oh. . .I get it now.
Yeah, when I say "groove width", I mean the front-back width of the milled-out slots (not their "diameter", which is the same as the rail "width"). That's where Picatinny and Weaver rails vary.
Of course the width of the rail width has a spec too (its 0.835"), but since the mounts themselves screw down and can easily adjust to rails that are either too wide or too narrow, so long as its "in the ballpark", rail width barely matters.0 -
Thanks! I wasn't correctly understanding what groove we were talking about. My misunderstanding. 0
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