Scope Mounts for AR advise

[Cevans]

I have just recently acquired a Redfield illuminator 3x-12x scope and need scope rings to mount this on a AR15. The front outside diameter is 68mm and the scope body is 30mm. Can anyone tell me what size scope rings I need and where to find them. I am a complete novice at this, so I tried to research and had nothing but confusion as a result. It will likely go on the picatinny rail of an AR15.

Thanks in advance for your help......I'm old and the larger scope will help with my old eyes.....

[DBTN]

You will most likely need a cantilever mount that allows you to keep the mount on the upper receiver while pushing the scope far enough forward for proper eye relief.  I can't advise exactly what length though.  Look at the offerings form Large, ADM, Bobro, and Midwest Industries.  You will most likely not be able to use standard rings and properly mount the scope on an AR.

[southernasylum]

Aero Precision makes some great cantilever mounts.

-southernasylum

[DaveTN]

63mm is a big objective. All AR’s are not he same. It depends on the type handguards you have. To be certain, you need to know the distance from the top of the handguard where that 63mm objective would be, to the top of the picatinny rail.

[Omega]

More than likely you will need a riser or a high mount set or rings.  My 50mm just barely sits above the hand guards (flat top), any bigger and it would be touching I'd think.  Something similar to this, but be sure to measure from the centerline of your lense to the bottom of your scope to make sure it will clear the rail.  

 

https://www.cheaperthandirt.com/parts-and-accessories/parts-by-gun-model/ar-15/mounts/scope-and-sight-mounts/

[xtriggerman]

A common mistake in selecting a scope for the AR is the fact that it is not large objective friendly with the common full top rail. The scoping geometry of the AR pretty much maxes out with a 40mm objective IF you want the gun to handle with a good check weld and your close to medium range sight ins are relatively close as in point of aim. A 40mm gives you 2 1/4" above the line of bore.  A 68mm is going to put you some where around 3 and 3/8ths above the bore line.  Mounting high over the bore is never good for holding a greater zero'd point of aim with in short to medium ranges.   Its like instead of watching your bullet fly from the back side of the bullet, your looking down at it from above its flight path. Leupold fought the whole marketing of greater light transmission with anything bigger than 40mm for years with data but in the end it was easier to sell scopes with the "bigger is all ways better" schtick to the general public. A 40 mm can be mounted with basic Weaver extra high rings. Good luck on finding a good fit for a monster like a 68 mm.

Edited December 1, 2020 by xtriggerman

[The Legion]

I have this mount for sale on the site. 

 

[TGO David]

WIth that large of an objective lens, you're going to need a mount that puts the midline of the optic at 1.93" or taller.

 

[Capbyrd]

Quick note for everyone.  The objective itself isn't 68mm but rather that's the outside diameter.   The objective is (or should be) 56mm.   It's still a large diameter but not as big as it sounds when you use the OD.