Rifle Scopes Does a true 100% RtZ scope mount exist?

[earthquake]

Looking for a 1-pc scope mount for my switch-barrel rifle that is easy to take on/off during barrel changes, that has a repeatable return to zero.

Maybe I don't have a true switch-barrel, whatever the vernacular is for them these days, but I do home barrel/caliber swap on the regular, and have to remove my optic to do so. It's somewhat annoying having to rezero the scope all the time. Currently using ARC M10 rings.

How is everyone else doing it?

 

[Olen_4504]

I use badger steel rings. not even a 1 pc mount.

i've taken the scope on and off (scope still in the rings, just removed the rings from the base) and done a barrel swap and reinstalled scope/rings and zero didn't shift at all.

 

[MOUNTIC]

A good once piece mount and proper torque seem to work best for me. I make sure my surfaces are clean before tightening. I just put a little clp on a rag and wipe it all down.

I have personally have had the best RTZ with Geissele mounts that I use on my gas guns. Spuhr on my bolt guns have never given me issues either.

 

[bourbonbent]

In my experience, Spuhr mounts and Badger rings and one piece mounts + torque wrench and consistent process gives less zero shift than the scope can make an adjustment to compensate for.

If it shifts much, something’s changed, like particulates on the contact surfaces causing mechanical misalignment that is not attributable to the scope mount/rings or any other equipment based failure, it is operator error by failing to check that all surfaces are clean.

Assuming that all parts are square and straight independent of each other, no additional stresses are created during initial mounting, and that proper cleaning and reinstallation is conducted, return to zero should be literal and exact with a quality ring like Badger, or one piece mount like Badger and Spuhr, should be the norm. I personally see more zero shift from a clean, cold bore to a fouled one. I have also had good experiences with Seekins rings, but it’s been a decade or more since I last used them.

 

[AIAW]

You may want to give these links a read.

https://www.snipershide.com/shooting/threads/eratac-mounts.6901299/

TESTED: The Repeatability of the AXMC and Era-Tac QD Mount

EuroOptic: Guns, Glass, & Gear - - Ever wonder how quick detach rifle components and accessories affect the repeatability of precision shooting setup? Well Derek did - and he made a special trip to the range with the Accuracy International AX, Tangent Theta Scope, and Era-Tac QD Mount to get...

www.eurooptic.com

 

[Aescobar17]

Try removing the glass and remounting the optic several times without removing the barrel. I’d be willing to bet that your issues are with the barrel removal more so than the optic removal.

 

[Aescobar17]

And not implying that the optics don’t contribute, but I’d bet they’re minor while the barrel swap is a larger factor.

 

[phantomskittles]

Agree with Aescobar17 it is probably more the barrel swap if you have quality rings and mount. I use Seekins rings and have taken my scope off before a match and had it return to zero when I put it back on with no difficulty.

 

[earthquake]

Thanks for the advice, all good thoughts. I hadn't considered the barrel causing this. I'll keep experimenting and look into all these options and tips.

 

[Nik H]

I don't know about the rest of the people here but I check zero every time I shoot. Wouldn't this be the easier path?

I have tried a bunch of mounts but never have seen a "truly" RTZ mount. Best one I have tried is the ERA but have not tried a Bobro or Spuhr yet. The errors are small but definitely non-trivial if you are shooting at distance.

Checking is fast and easy and any measured offset is quickly entered into your ballistic solver. Zero is affected not only because of mechanical changes to scope, mount, barrel but also due to lighting conditions on the day you shoot versus the last time you zeroed the rifle.

 

[alicea8541]

Thanks for the advice, all good thoughts. I hadn't considered the barrel causing this. I'll keep experimenting and look into all these options and tips.

You can always just stop changing barrels every week. Dry firing doesn't wear them out. BDSS!!!

 

[Primus]

To actually awsner the OP, no.

It's virtually impossible and there will always be some measurable ammount of shift. The question then becomes who minimizes this the best in a easy and repeatable process that is acceptable.

Some shift half a moa, some a quarter some a 10th, some 100th. But there is no such thing as an absolute return to zero when dealing with these types of interfaces and fitments.

 

[atepointer]

FWIW there is a guy on the lease with a Blaser that he changes barrel out all the time and he is always having to mess with scope zero. Scope is g2g as long as he doesn't swap barrels....that solved the problem quickly knowing it wasn't glass or mount, but rifle related. Forget what caliber he stuck with last season, but no more 'scope' problems.

 

[charnicus]

I couldn’t recommend the likes of Spuhr and ERA TAC more. Specifically their non QD offerings. I frequently take the scopes of my gassers during maintenance. I think RTZ can only closely be attained but as @Primus said there will always be a an immeasurable by practical mean to measurable difference on paper.

 

[rob.sfo]

I have multiple Bobro QD mounts that i have had good luck with . I can't afford all the optics I need so I move them around regularly. I'm not an expert but I did a lot of research on this topic and seems like Bobro does it right.

Here's a review from a supposedly reputable source...

Review of the Bobro 34mm Cantilevered Precision Optic Mount

BigJimFish reviews the bobro 34mm cantilevered precision optic mount for quick release mounting of rifle scopes.

www.snipershide.com

Here's a good thread on the topic from this forum...

http://www.snipershide.com/shooting/threads/true-return-to-zero-mounts.196121/

Another from the m4carbine forums...

ADM VS Bobro Scope Mount?

I like them both. The ADM has two locking points the Bobro has one. The logical choice would be adm with two, but many people like Bobro so I was wondering why I would want that over the adm that has two locking points... Specific mounts are ADM Recon and Bobro B03-200-300-R1 Thx

www.m4carbine.net

 

[Darqusoull13]

My experience in moving 2 optics around on 4 guns is Bobro mounts always return exactly where they were on the same gun. My buddy has moved his optic between guns as well. Boro design is solid in my experience.

 

[deersniper]

Pretty sure GDi has the least zero loss of any QD mount.

But a unimount and a t handle torque wrench is probably the way to go unless you need to be able to QD the scope in field to access irons or something

 

[RTH1800]

I spend an inordinate amount of time establishing a no wind zero at longer type range. 600-800 meters. I mean absolute zero. I shoot at dawn, at dusk and at midnight if needed to get that zero in a no wind condition. I shoot both directions on the same range to verify. No way I give that up prior to a needed barrel change.

 

[Primus]

Pretty sure GDi has the least zero loss of any QD mount.

But a unimount and a t handle torque wrench is probably the way to go unless you need to be able to QD the scope in field to access irons or something

Pretty sure...you are wrong.

 

[deersniper]

Pretty sure...you are wrong.

Maybe when you can afford nice stuff you won't be such a fanboi for stuff that breaks from normal use.

I'm done with Bobro mounts. Updated #4 in OP. Replacement received. New video of moving mount. > Optics, Mounts, and Sights > AR15.COM

I have two Bobro mounts. A 30mm single lever mount and a 34mm double lever mount. Last year I had the 30mm quit holding zero after about 400 rounds (estimated). My groups went to 3+ MOA and I could

www.ar15.com

Sorry gdi is too much $$$

 

[littlepod]

I use ADM QD mounts and I've removed and re-attached the scope multiple times and it has maintained zero.

 

[Brasscow]

FWIW there is a guy on the lease with a Blaser that he changes barrel out all the time and he is always having to mess with scope zero. Scope is g2g as long as he doesn't swap barrels....that solved the problem quickly knowing it wasn't glass or mount, but rifle related. Forget what caliber he stuck with last season, but no more 'scope' problems.

3 blaser r8s and 5 scopes in blaser mounts here.

Every single one repeats with absolutely no adjustment necessary. They’re incredible. If his rig is factory blaser parts he should not be having ANY problems. If your blaser is a 1/2 minute rifle you can take it down to bare nuts & bolts and reassemble it between each shot and you’ll shoot a 1/2 min group.

Wish i could say the same for my NF/seekins/badger/bobro rings and unimounts and my multiple AI rifles on barrel swaps. They’re close - within .1 or .2 mil on scope swaps and around a mil on barrel swaps, but the blasers repeat with no adjustment necessary... and i mean NONE.