Cantilever scope base question.

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  • jy951

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    What is the reason for cantilever scope base/ rings. I can see if you want to position the optic ahead of the rail, but I see no other reason. They appear like they would not be as stable as a standard mount. You see these mainly on ar15 mounts. Can someone please explain what the point is?
     

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    M67

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    On ARs and some other rifles, it's just an extension ring so you can set the eye relief properly. On certain rifles where you can cut down the length of pull and you cram your face against the action, and with the eye relief from a scope being 2.5-4", you might need to move the scope forward to get a proper FOV. As long as the mount is solid (quality) it's still a 1 piece system and is very strong. Same system as the old style extension rings made by Leupold, Millet, Weaver, etc. for certain bolt guns (granted it's not to compensate for a super long action and a short tubed scope)

    On shotguns where the cantilever is on the barrel, you're bringing the scope to you to 1) set eye relief but 2) for turkey and waterfow where you're probably just using a bead or iron sights, have a scope rail on the receiver is a PITA cause you can't see your aiming system with the field (non rifled) barrel.

    This system is solidish, if you drop the gun or the barrel the cantilever can bend and flex which would change your zero, and when you take the rifled barrel off and reinstall it chances are the zero has changed a bit. This system just saves you from drilling and tapping the receiver and for quicker versatility. But if your scope lacks the internal adjustment to get zero'd, you can purposely flex the cantilever into giving you enough adjustment to get sighted in
     

    DeadeyeChrista'sdad

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    I have an old hastings cantilevered barrel and scope for my 1187. It was my go to back in the day. Just take it off at the end of season and set it in a corner of the safe. Come the next year just throw it back on and double check the zero. Absent a good jolt, it never changed.
     

    jy951

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    In the pic above, it seems unnecessary and not as stable as a standard style mount. That one is extreme, but I see no reason for it on most ars other than it might be tacticool.
     

    ol' poke

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    I have one on my A4 AR flat-top. I like it better than the 2-piece rings for just that reason. I just have one connection to make. It's a quick-release to boot, so it's easy on and easy off when I want to back to the A4 sights.
     

    justacog

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    Besides eye relief adjustment, I always thought it also had something to do with trying to help manage the propagation of the percussion shock to the optic by keeping the connection point centered above the receiver after adjusting for eye relief. Some shotguns and higher caliber battle rifles can be punishing to optics. I've also heard some air rifles can be hell on optics because of a high impulse shock wave.
     

    M67

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    In the pic above, it seems unnecessary and not as stable as a standard style mount. That one is extreme, but I see no reason for it on most ars other than it might be tacticool.


    How would it be unstable? It's one solid piece of aluminum. It projects forward but it'll not like it's going to flex

    I typically shoot ARs with the stock at the second position. You get some scopes with long eye reliefs you have to move it forward just to get a proper field of view

    I have an older Trijicon TR21 and at 1.25 power the eye relief is like 4.5 inches

    And about 500$.

    Sphur seems to make the Rolex King Tiger tank of mounts.

    MH

    "Only" $400 for the non QD. I have one Spuhr and it is probably one of my favorite mounts just got the sake of the machining and thought that went into it
     

    gmcttr

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    In the pic above, it seems unnecessary and not as stable as a standard style mount. That one is extreme, but I see no reason for it on most ars other than it might be tacticool.

    If a non-cantilevered base or two separate bases were used, most of a one piece base or the front base on a two piece would be on the handguard and not good at all. You want the entire base/bases on the receiver on an AR.
     

    ljk

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    The ideal location for the scope rings is on the upper receiver, not the handguard/rail.
     
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