What is a Weaver mount?

by B.B. Pelletier

A reader asked this question last week, “Just what is a Weaver base and how is it different from other scope mounts?”

History
Back in the 1950s and 60s, firearms did not come with scope mount bases. Gunsmiths made a living attaching scope mount bases to guns so a set of rings could be attached. There were lengthy articles in gun magazines about drilling and tapping receivers for mount bases. They still do some of this, but many of today’s firearms come with scope bases already on the gun – some of them built right into the design.

Scope mounting was such a hassle back then that several companies sprang up to help solve the problems. But scope companies had a lot riding on the ease of mounting their products, so Weaver designed a type of scope mount base that is still very popular today. It’s easy to attach, yet it provides a solid scope mount. It is a wide dovetail (0.617″), but the most important feature is the presence of several slots running across the base. These slots accept keys, which are on the bottom of the scope rings. Those keys keep the scope rings in one place when the gun recoils.


B-Square Weaver base shows the slots for the ring keys. This one is for a specific gun, but Weaver rails also come as bulk extrusions that a gunsmith can cut to fit.


This key on the base of a B-Square Weaver ring fits into the slots on the Weaver base. They will also fit the slots on a Picatinny rail because they’re thinner.

It wasn’t popular to mount a scope on an airgun at the time Weaver mounts came into being. When shooters finally did start mounting them in the 1970s, the Weaver mount wasn’t used. At first, companies such as BSF, Diana and Weihrauch used the raised rails on their rifles for diopter sights as their first scope mount bases, but over time most of them progressed to a wider dovetail – the so-called 11mm dovetail that in reality extends from 9.5mm to 13.5 mm. The Weaver base would have served them well, but they never used it.

Today, the airsoft crowd uses Weaver mounts more than the pellet and BB gun crowd because of their ties to the military. Back in my day, 40 years ago, the military had no good common way to mount a scope on a rifle. Every country and manufacturer did it their own way, which is why some sniper rifles look so odd today. Take a good look at a Mosin Nagant made for sniping!


Mosin Nagant sniper rifle looks extremely archaic with its high-mounted scope. Rifle was never intended for a scope when it was designed in 1891.

When the military finally did get around to standardizing their mounts, they borrowed the slot feature from the Weaver mount and improved it by placing the slots at regular distances from each other. Finally, there was a standard mount base that could use standard equipment. Best of all, the Picatinny rail, as it is called, has wider slots than the Weaver mounts, so Weaver rings will fit a Picatinny base! A Picatinney slot is 5mm wide, while a Weaver slot is 3.5mm.


This Tri Rail has three Picatinny rails extending from the front ring. The slots are wider than Weaver slots and spaced closer together for ease of adjustment.

Picatinny extrusions come in standard lengths that a gunsmith can cut to fit a particular job. And, the mount market is red-hot for Picatinnys right now!

When you see the Picatinny rail, the value should be obvious. It is the Lego block of the scope mount world. Positioning scope rings is easy, and they’re held tight against shock and recoil by the cross key. Unfortunately, airguns do not use them. The first company to try will meet a storm of protest from the shooters who have a heavy investment in 11mm equipment, but Picatinny is by far the better system for mounting a scope.

23 Responses to “What is a Weaver mount?”

  • hb Says:

    sorry to post again but,
    would you recomend my buying the gamo compact in the near future, or waiting to get the izh 46. Would it be worth the extra $80 for the izh. I’m not concerned with weight, just accuracy, trigger pull, and easy of operation. I could go with the 747 because I’m just getting this for fun / club competition (for now). By the way, I just shot a 79/100 with a walther cp sport. Heavy trigger= dropping 21 points. not too shabby though.

    thanks keep up the excellent work

  • Anonymous Says:

    “BB” –
    Why has the industry resisted Weavers for springers? It seems a design that makes sense, given their recoil habits –
    Also – are you actually Tom Gaylord in your spare tome? You sure write like Gaylord…

  • B.B. Pelletier Says:

    The airgun industry is older than the Weaver mount. And they were not focused (pun intended) on scopes in the 1970s. When Robert Law of Air Rifle Headquarters started scoping air rifles, he was breaking new ground. He had to find ways to make it work and the airgun manufaturers were not very accomodating.

    Also, don’t make the mistake that the airgun manufactures know much about their guns beyond how they work. Many companies are completely out of touch with how their guns are being used – even today!

    For example, the German makers all think 12 foot-pounds is a magnum air rifle! We know differently in the U.S., but their major market is the UK, and there 12 foot-pounds is the maximum.

    And the Brits aren’t much better. Only those few companies who come to the SHOT Show and take the time to talk to Americans understand our market. The rest are in the dark and think we all shoot 70 foot-pound guns and can’t hit a barn from the inside.

    B.B.

  • GadgetHead Says:

    Hi B.B.,

    Have you heard any updates about how the Diana scope mounting rings project is coming along?

    Cheers,
    GH

  • B.B. Pelletier Says:

    GH,

    Nothing yet. I expect to hear in four or five months.

    B.B.

  • Don Says:

    B.B. Thanks for the informative article. Its too bad that airgunners did not go to the Weaver or Picatinney bases years ago. Perhaps we wouldn’t be fussing so much about ineffective scope stops with our dovetail bases? How many times have we lamented on Power Springers and their scope problems. I, for one, would like to see us change even though I have several.”powerful springers”.

  • Anonymous Says:

    thanks for your insight on the target guns.But I left out crosman’s co2 target pistol. Is that even in the same league. I don’t mind co2 as long as its consistent for 60 shots

  • Anonymous Says:

    BB,

    I saw that you described in another post how a TalonSS owner tuned his gun. Could you do a post on how to adjust the tophat? My condor is getting about 10 full power shots, but I want to get more consistent shots at lower power setting. Thanks.

  • hb Says:

    From the crosman and daisy which one.
    from compact and 46 which one.
    sorry for all questions, just want to make the best purchase possible. 10 meter is one of my favorite things. I shoot 10 meter precision air rifle (anshutz guns and one FWB for international air) and 50 precision small bore (anshutz guns) in high school. awesome experience. Going to nationals this summer

  • Vince Says:

    BB – I can’t hear about “Picatinny” rails without thinking of my first engineering job out of college – small cal weapons at Picatinny Arsenal. My second day at the job my boss puts a sub-machinegun (M231) on my desk and says “See if you can take it apart and figure out how it works”!

    Oh, well…

    I finally got an MP513 today (from a vendor who delivers to NJ) – and man, that thing is something out of the ordinary. Very large, unexpectedly light, very military-looking, kicks like a mule, very hard to cock and tiring to shoot. Not the gun to shoot when you wanna relax… but there is something oddly attractive about it.

    Don’t remember if you mentioned it way back when in your review, but it appears that the safety is really a hammer. The trigger releases the hammer but the gun doesn’t actually shoot until the hammer hits a release for the piston.

    Kinda wishing I had been able to get a .22, but the place I ordered it from only had .177′s.

  • Anonymous Says:

    can an airsource gun that has enough clearance accept a 9oz co2 tank? i might get one if that was the case. even a 9 oz would provide 1000′s of shots

  • dm20 Says:

    speaking of scopes ad their mounts, you usually tout the leapers scopes as best for the money. i have no doubts, but the price range for scopes is huge. i was shocked to see a friend of mine scope his 30-06 deer rifle with a $400 scope!
    i pointed him towards the leapers, but he just smiled and assured me his was superior to my “pellet gun” scopes. i can imagine shooting a deer rifle would make the smallbores a bit wimpish.
    in the world of scopes, does the savage/weatherby analogy apply, or is it something with the optics that changes the price margin?

  • B.B. Pelletier Says:

    Crosman CO2 guns,

    What are you referring to? I don’t know who you are and I have no idea of which target guns you refer to. I communicate with 20-40 readers each day – some of them responding to blogs posted two years ago.

    Please tell me which target guns you mean and which Crosman CO2 model you refer to and I will answer your question.

    I’m not angry, but with all the traffic we have, it gets confusing unless the question is more specific.

    B.B.

  • B.B. Pelletier Says:

    Condor owner,

    Perhaps I can help you, but I need to know more about your gun.

    Please tell me how you qualify the “10 powerful shots.” A Condor should get at least 20 powerful shots.

    Are you expecting a velocity variation of 20-30 f.p.s.? If so, you will be disappointed. To get 20 shots, a Condor may have a velocity spread of 75 f.p.s. But at 50 yards, the groups will still be tight, because the pellets used to measure max velocity are never used for accuracy.

    So please tell me more about your experience and I will try to help.

    B.B.

  • B.B. Pelletier Says:

    hb,

    When you go to the nationals in July, be sure to stop at the Pyramyd Air booth and say hello.

    Daisy, IZH 46M.

    If you shoot an FWB, you understand good target guns. Why fool around? Get the IZH 46M if that’s what you can afford. I shot one in regional competition for a year.

    B.B.

  • B.B. Pelletier Says:

    Airsource,

    Even with enough clerarance, there is still the problem of threads. Paintball tanks don’t have the same thread pattern as AirSource. You need an adaptor.

    Google it.

    B.B.

  • B.B. Pelletier Says:

    dm20,

    I have owned and used Leupold scopes (your $400 brand) and the Leapers scopes I tout are superior to them in every way. EVERY way! Leapers are clearer, brighter, have better reticles and crisper adjustments.

    Specifically, almost any Leapers scope will best a Leupold Vari-X II in all categories. I sold my Leupold Vari-X II because it wasn’t significantly better than any Tasco or Simmons (cheap scopes) I owned.

    Now, there are Leupold scopes that are superior to Leapers for clarity (though not brightness. The Vari-X III series is an example. They are more expensive, and they are worth the price. But a run of the mill $400 Leupold isn’t anything to brag about.

    B.B.

  • Anonymous Says:

    BB,

    Correct me if I am wrong, but I believe that the Umarex Desert Eagle comes standard with 2 Picatinny rails, one of which is detachable. So at least in the realm of replicas the airgun community has made a small foray into the Picatinny world.

    Keep up the good blogwork!!

    Phil from AZ

  • B.B. Pelletier Says:

    Phil,

    Right you are! As I wrote the blog I was thinking about recoiling air rifles and I overlooked the modern pistols. Some airguns therefore DO come with Picatinney rails!

    Thanks,

    B.B.

  • Erikusan Says:

    I have both an M14 and a VSR-10 (AGM model), both springer airsoft rifles, and both have picatinny rails, unless I’m mistaken. However, I can’t for the life of me seem to get my scope rings on. Any suggestions? Please email me at erikusan is me at juno dot com. (Make that all one word)

    Many thanks, and happy hunting!

  • B.B. Pelletier Says:

    Erikusan,

    Weaver mounts fit on both of these guns easily. I have done it.

    Are you sure you have Weaver mounts? Do the bottoms of them look like the ring in this post (the second picture)?

    B.B.

  • Erikusan Says:

    Yessir indeed they are identical to the ones in the lower picture.

    According to the VSR-10′s description, it uses a Picatinny rail, but obviously the description is mistaken.

    Thanks to the wonderful Customer Service department, I’ve ordered some Weaver scope rings that should be arriving in a few days.

    Many thanks!

  • B.B. Pelletier Says:

    Erikusan,

    As this post mentions, Picatinney rails will accept Weaver mounts. The gun comes with Picatinney rails.

    B.B.

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