Rifle Scopes Ring Height Info - How to Measure Correctly

[PKT1106]

Re: Ring Height Info - How to Measure Correctly

Can anyone confirm using Burris XTR lows on a Savage 10FP with an EGW 20MOA base and a Vortex PST 6-24x50?

My numbers say I will be clear by 4-5mm, but I want to know if anyone else has this setup.

Thank you.

 

[shorthairs]

Re: Ring Height Info - How to Measure Correctly

Great thread. Thanks to all that participated.

 

[OutRider]

Re: Ring Height Info - How to Measure Correctly

...I now see why my scope ring thread was ignored (lol) but I still never saw much about ring hight for M1A...

...I did not realize mounting glass on an SA NM M1A would be such a can of worms...

...my good buddy is going to love this...he has been berating me for spending so much on an "old" rifle...

 

[GunDudeUSA]

Guys,

The calculator that was mentioned in this thread is no longer active (link doesn't work). I went ahead and created another calculator based on the information that was presented in thread. Enjoy.

Link: Scope Ring Height Clearance Calculator

It has the following features:

1. Preset values for objective bell for most common scopes i.e. Schmidt & Bender, US Optics, Kahles, Nightforce.
2. Preset values for ring heights for most common rings i.e. Seekins, Badger, Spuhr.
3. Has offset adjustment for Butler Creek scope covers.
4. Has calculator to get offset for scope cant (from 0 to 50 MOA).

Feedback appreciated.

 

[50MOAshooter]

OK so I am a newbie with a dumb question, mainly because I doubt my mathematical skills. I have a ruger no.1 in 7mm that I just put Leupold 30mm "high mount" rings on. Part number 51042. The rear ring is .125" taller than the front ring and they are only 3.593" apart from very end to end. I come up with like 140 MOA. Can that be right?!? My scope only has 75 MOA of vertical adjustment.

 

[woodspider]

I just put together my Rem 700 Sendero with the new AICS AX LA . I Have a bushnell HDMR 50mm obj on the way from Dealer... Can someone tell me what 34 mm ring height will work best with this set up and with Butler Creek Caps. Thanks in advance for replies.

 

[Pleistarchus]

Sorry boys, Even as an amateur I have to disagree with the majority of you and go with Mr. Potterfield Gunsmithing - How to Determine the Proper Scope Ring Height - YouTube . Doesn't matter what the numbers say, if I am uncomfortable where my head sits looking through the scope.......well heck with the numbers. What if your 6' 10" and your head is the size of a beach ball, does that mean my head will have to be at a 90 degree angle to be able to look through the eyepiece?

 

[mhuff]

Definitely a good video. John explaines it well.
https://www.youtube.com/watch?v=EB-DwEtwG10&feature=youtube_gdata_player

 

[Wayfaerer320]

Very handy - thanks.

 

[Chris dore]

Need help! I'am having a .260 built by GA Precision with the templar action 20MOA base on a AICS stock the rifle will be left hand..my issue is I've purchased a Schmidt & Bender pmii 5-25x56 which I know will have to be on fairly high rings to accommodate the scopes illumination knob, my question is do I stick with the 20 MOA base and purchase 0 cant rings or purchase 20 MOA rings as well to get the most out of the optic.... I would like to use one of the Spuhr.

 

[Chris dore]

Again any help is greatly appreciated.

 

[shooter6.5]

You are having a great weapon built by one of the best in the business.

Seriously=ask George. He will know. I have one he built and it is a great weapon.

 

[Chris dore]

I will, thanks again.

 

[glassbeaver]

Tag.........

 

[DMW32/16]

To clarify, here's the math I cam doing that tells me LOW will not work, MED will not work, and HIGH will get me only about 2mm clearance:

LOW = .937 " = 23.7998 mm
MED = 1.062 " = 26.9748 mm
HIGH = 1.187 " = 30.1498 mm

Remember the Objective Bell Diameter: 55.8mm

Using the HIGH set of numbers for the mount:

30.1498 - (55.8 x .5) = 2.2498mm

Am I off in the weeds here or is this good math? Seems I should have more room than that for covers...

maybe I misunderstood, I see you converted all the measurements to mm. I did the opposite and converted them to inch leaving me .140 clearance with 55mm outer bell ie 2.16535 rings .823 standard badger and .400 for the 20 moa badger base.
the catch is the x.5 at the end depending on which unit is correct the constant would change the result and would not be the same for both metric and standard.

edit I re did all the math both in st and metric results .140" if I do the math in standard .160" if I do it in metric. (converted both to inch for ya at the end ) aka 4.1 mm metric vs 3.5 mm in inch formula. 20 ths or (.020) isn't a lot but its enough to make the difference in some cases.

{also your formula didn't seem to add the base? anywhere from 6-12mm ish depending on brand and moa size.} is this for a reason?

 

[relentless1]

Thanks, that helps

 

[relentless1]

Thanks, that helps

 

[earthquake]

Is there any consensus on what scope height is "ideal"? Or is is all personal preference? Should one go as low as they can get? Or can you go higher and not have any issues? What's the reasoning for getting low with the scope? Thanks.

 

[30mm]

Guys,

The calculator that was mentioned in this thread is no longer active (link doesn't work). I went ahead and created another calculator based on the information that was presented in thread. Enjoy.

Link: Scope Ring Height Clearance Calculator

It has the following features:

1. Preset values for objective bell for most common scopes i.e. Schmidt & Bender, US Optics, Kahles, Nightforce.
2. Preset values for ring heights for most common rings i.e. Seekins, Badger, Spuhr.
3. Has offset adjustment for Butler Creek scope covers.
4. Has calculator to get offset for scope cant (from 0 to 50 MOA).

Feedback appreciated.

Calculator works great, thank you for posting.

 

[cz777]

The most ideal way to see what rings your need for the stock you have, according to your melon, is to see just were your eye aligns above the bore. If there was just such a device you could put on your rail with a graduated scale showing you just were your eye align above the bore WITH the rail you have selected. Hmmm....

With these, I can tell you within two minutes where you head aligns in the off-hand, kneeling, and prone positions. The graduations are 0.100". Also with the measurement, it will tell you if you will clear the objective of your favorite scope or not. Why fit you to the scope when it should be fitted to you?

where do you get this tool from ???

 

[forrestgump01]

Good info , this helps a lot !

 

[zac_c]

This thread has been really helpful thanks

 

[LoanHarvey]

I have the same issue with my 700CDL with a 20MOA Base and TPS Rings. The Bell of the scope will hit the front of the picantinny rail if I move it back far enough for proper eye relief.
The bell sits plenty far above the barrel, so I don't want higher rings. I heard one option would be to trim back the front of the rail, but I have not attempted that. Just an fyi.

 

[CaptT]

Thanks for the info.. Shopping a scope as we speak.

 

[Keith E.]

Couple of setups here for reference:

1. M40A3 clone-type; Badger Ordnance 20moa base; Nightforce 30mm, 1" high, steel rings; NF NXS 5.5-22x56 with Butler Creek flip-ups. Clears with no issues. other than thinning the part of the objective cover closest to the barrel. It's closer than some may be comfortable with but I have had no issues with it so far.I will update later with a measurement.

UPDATE: Had to thin the part of the objective cover closest to the barrel. It's closer than some may be comfortable with but I have had no issues with it so far.



2. Remington 5R with the same base and scope but with Leupold MKIV 30mm, .840" high steel rings and no Butler Creek flip-ups. Clears but at <.050". Will evaluate and update if any issues are encountered.

UPDATE: Changed the .840 rings to 1" high, steel rings. Scope easily clears now with Butler Creek flip-ups.

Keith

 

[aahunt03]

good thread

 

[Monchichi]

Really good info...thanks for all the helpful posts. Got my scope...now I'm ready to get my Spuhr mount.

 

[jmbd2112]

thanks for the info, just bought a new optic and trying to figure this out....

 

[Cdog1157]

Holy cow, there's alot of info in this thread and I know it's an old one but hoping someone has the same setup I'm going with. Savage model 12 LRP in 6.5 CM with Vortex 6-24x50 optic. The farthest I'll ever shoot is 600 yards and probably do more at 200 yards. Do I need a 20 moa base for that? I used that calculator and it said I needed extra high rings which i don't think is right. Was hoping to have everything here by Friday so I could shoot it over the weekend but Guess i'll just have to wait til i get the base & scope to measure.

 

[Guest]

LawnMM

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Re: Ring Height Info - How to Measure Correctly
10/24/2014 Last edited 11/08/2014 by tucker301
(5 votes)

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Helpful link...

http://www.mil-rad.com/scope_ring_calculator

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KITTYCATMANX26 MONTHS
Premium Member
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Re: Ring Height Info - How to Measure Correctly
11/30/2014
(2 votes)

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Getting the objective as close to the barrel as possible is a conventional rule of thumb, but I find it less important than most folks believe. Obviously, you don't want to have an absurdly high mount, but I have found situations where I need to mount a bit higher. In particular, you will want to make sure that the objective height will synchronize with a clip on NV or thermal scope you may want to add. In this case, you may need more clearance, and it generally comes without much detriment as it's more important to synchronize your scopes. Also, extremely low mounting can leave you more susceptible to mirage.
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Wesquire91XGunny Sergeant
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Re: Ring Height Info - How to Measure Correctly
12/10/2014
(2 votes)

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I have a 50mm obj, but with an MTU contour, I only have .04" clearance with medium seekins rings + EGW HD base. Had to buy high rings, which is still really low.

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ColdBore88XSergeant
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Re: Ring Height Info - How to Measure Correctly
03/16/2015

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What about on AR? Sorry to ask another quesiton about this. I have a .308 that I am looking to put a Leupold 3-18 X 44 on.
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mrshooter

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Re: Ring Height Info - How to Measure Correctly
05/11/2015

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Glad I found this formula. I'm looking to see what will work best on my mega maten
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YamaArashi

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Re: Ring Height Info - How to Measure Correctly
06/25/2015 Last edited 06/25/2015 by YamaArashi
(5 votes)

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Remington 700 action - TacOps 24 MOA base - Krieger M24 contour - Nightforce 30mm tube, 50mm objective lens - Rings 0.97" top of rail/base to scope centerline
= 0.1425" bell clearance

Defiance Deviant action - 20 MOA rail - Krieger M24 contour - Vortex 34mm tube, 56mm objective lens - Rings 1.00" top of rail to scope centerline
= 0.06" bell clearance

AR flat top - 0 MOA rail - SWFA 30mm tube, 42mm objective lens - 1.44" mount from top of rail to scope centerline w/ 10 MOA cant
= 0.40" bell clearance

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FotheringillXCorporal
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Re: Ring Height Info - How to Measure Correctly
07/08/2015
(1 vote)

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If there is still trouble figuring things out, go to Midway's site, pick your scope and scroll down. They will give the exact dimensions of the scope at critical points. Then go to its site for ring and/or riser dimensions. Then figure out if rings and/or risers will give you enough room.





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outsidetheboxAUXPrivate
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Re: Ring Height Info - How to Measure Correctly
07/09/2015
(2 votes)

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I use the Precision Rifle Products right height scope tool.

Just slide it on and set the scope to the proper height, check and order rings.



No muss no fuss.



OTB

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MozellaXPrivate
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Re: Ring Height Info - How to Measure Correctly
07/28/2015

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Careful........ when searching for scope rings you may encounter a "height" measured from the bottom of the scope ring to the center of the tube or to the bottom of the tube. Or, it could be from the top of the mounting surface. It's not easy and sometimes frustrating trying to find out what scope ring makers are actually talking about. And some just say low, medium, and high while doing their best (apparently) to hide the actual measurements. What's more, one manufacturer's "high" might be lower than another brand's "medium". Use caution.

Then there is the problem of barrel contour and/or a base which is tilted relative to the bore; i.e. a "20 MOA base". If I have a sporter barrel contour, my set up may not work for you if you have a bull barrel contour.

One of my rifles has a mounting surface on the action which is higher for the rear ring than the front ring. Of course, that means I have have to shop for special rings or mounting bases.

Bottom line: Do good research and if you're not absolutely sure your choice will work, be sure the vendor has a good return policy. This ain't rocket science, because rocket science makes sense. Selecting scope rings sometimes doesn't make sense at all.

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YamaArashi

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Re: Ring Height Info - How to Measure Correctly
08/15/2015
(5 votes)

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Defiance Deviant action 20MOA rail - Krieger M24 barrel

Clearance measured toward end of sunshade.


Seekins 34mm 1" height - Vortex Razor Gen II 4.5-27 = 0.06" clearance

Seekins (Vortex branded) 34mm 1.1" height - Vortex Razor Gen II 4.5-27 = 0.154' clearance

Seekins (Vortex branded) 34mm 1.1" height - Nightforce ATACR F1 5-25 = 0.157" clearance

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Redmanss

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Re: Ring Height Info - How to Measure Correctly
09/03/2015

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LawnMM wrote:
Helpful link...

http://www.mil-rad.com/scope_ring_calculator​

Is this a dead link now? I'm not getting anything.

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MarinePMI

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Re: Ring Height Info - How to Measure Correctly
09/03/2015

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Sure looks like it. Bummer. That was a really handy calculator....

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Shadow722

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Re: Ring Height Info - How to Measure Correctly
09/05/2015 Last edited 09/06/2015 by Shadow722

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Action: Rem 700 SA 6.5x47mm Lapua

Barrel: Re-Purposed Truck Axle (actually a Broughton contour # 7.2)

Scope: Vortex Razor Gen II 3-18x50mm

Scope Base: Nightforce Steel 20 MOA

Rings: Badger MAX Alloy Rings 306-23, 34mm, Low, 0.915" Weight 4.0 oz

Scope Caps: Aadmount

I don't believe it's possible to go much lower than 0.915" with this Vortex due to how far the turret housing hangs below the scope tube. Other 34mm tubed, 50mm objective scopes may not have that problem. Seekins 34mm Lows 0.92" or ARC 34mm M10's 0.94" (24mm) or APA 34mm Standards 0.95", would have also worked as well here. But I'm not sure if APA's 34mm Lows 0.856" would work for this scope. It would be very close....IMHO

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MattDKXSergeant
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Re: Ring Height Info - How to Measure Correctly
09/28/2015 Last edited 10/01/2015 by MattDK
(1 vote)

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Redmanss wrote:

LawnMM wrote:
Helpful link...

http://www.mil-rad.com/scope_ring_calculator​

Is this a dead link now? I'm not getting anything.​

It seems to go down every week or so with a registrar or DNS error. Go back and try again later and it should be back up.

Facemelter wrote:

Here is the equation:
[rail height + ring height] - [bell diameter x 0.5]
If the value is positive, then your bell will clear the barrel.​

Regarding that, if you can't get to the online calculator the equation can be refined a little bit to manually add in the refinements in the web site link referenced above.

[rail height + center ring height + barrel taper height] - [bell diameter x 0.5]

Bell diameter should be measured with scope caps on or factored in.

Regarding barrel taper height, research your barrel profile and scope specs to ensure the initial barrel taper is not going to conflict with the position of the scope and *its* objective taper above it. Very low rings (~0.85") and fwd scope placement could make this a very close call.

If your scope has fold-down BUIS like an AR (or fixed like an M1A) you also need to calc the back side:

[center ring height] - [[ocular bell diameter x 0.5] + iron sight height]

No need to count rail height on an AR or similar where its full length.

If you are getting really detailed, scope cant from a 20 moa rail or similar might matter. Especially with a sunshade. That site has a dedicated calculator:

mil-rad.com/scope_cant_calculator

or do the math yourself as follows:

[tan[MOA cant x [1/60]]] x [length between front of scope to front of rail in millimeters]

EDIT:
cant is kind of tricky since its a multi-step thing. I did it manually with my Windows calculator set to 'scientific' like this (assuming a 20moa rail and 6" (152.4mm) of scope overhanging the front of the rail):

1/60 = 0.01666666666666666666666666666667
0.01666666666666666666666666666667 x 20 = 0.33333333333333333333333333333333
tan(0.33333333333333333333333333333333) = 0.00581782981095534485056207234306
0.00581782981095534485056207234306 x 152.4 = 0.88663726318959455522565982508158

Rounded, that last result is 0.9 mm. So the 20 moa cant reduces clearance on that scope as-positioned (with 6 inches of overhang in front of the rail) by just under 1mm.





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29aholicXFirst Sergeant
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Re: Ring Height Info - How to Measure Correctly
10/08/2015

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You also have to be conscious of the size of the zoom ring. Millett for example has a fairly large zoom ring and while I could clear my barrel easily, the bolt would not clear the zoom with medium rings.

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Redmanss

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Re: Ring Height Info - How to Measure Correctly
10/09/2015

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Good to hear that link is still running, even if it hiccups every now and then.

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woodlander

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Re: Ring Height Info - How to Measure Correctly
01/14/2016

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Very useful, will have to write this down.

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mushroomberger

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Re: Ring Height Info - How to Measure Correctly
03/30/2016

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Thanks! This is really helpful info to save time and money.

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SHGMAC

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Re: Ring Height Info - How to Measure Correctly
01/10/2017
(1 vote)

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LawnMM wrote:
Helpful link...

http://www.mil-rad.com/scope_ring_calculator​

That is awesome!

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SHGMAC

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Re: Ring Height Info - How to Measure Correctly
01/10/2017
(1 vote)

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ColdBore88 wrote: What about on AR? Sorry to ask another quesiton about this. I have a .308 that I am looking to put a Leupold 3-18 X 44 on.​

I have that exact setup. Was running this IMS for a few years...

... but ran out of elevation travel in my first Precision Long Range course. I upgraded to the 20-MOA version last year and I'm lobbing 308 out to 1,200M now

.

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davisj3537XSergeant
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Re: Ring Height Info - How to Measure Correctly
01/11/2017

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Remember to half the barrel contour clearance. Building onto MattDK's awesome post, I added this and his cant equation into his math. Using PEMDAS is imperative.



Rail Height + Center Ring Height + (Action Diameter - Barrel Taper at full scope length) X (0.5) - (bell objective X 0.5) - (base cant X 0.05) = Clearance



Remington's action diameter is 1.35 BTW; I don't know the other brands, but they have to be very similar. The number used for base cant will simply be the 20 MOA or 30 MOA...etc. The barrel diameter at full scope length can be extrapolated from any barrel maker's contour page.

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360moaXSergeant
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Re: Ring Height Info - How to Measure Correctly
Sunday at 9:30 PM

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The info above is all good to figure out the mechanical clearance needed for a particular scope. But this is not where people should start in their search for proper scope height. The most important factor is shooter comfort. If you get the lowest possible scope height over bore, but find this is not comfortable, you will be doing yourself a grave disservice. People differ in neck length and distance from body centerline to shoulder pocket.

The only argument I've heard for minimizing scope height over bore is to minimize cant effects. But this argument is erronous -- there are multiple solutions to keep your rifle level (bubble levels of all kinds) and the effects of rifle canting are generally over-exaggerated.

Getting a comfortable scope height is much more important than minimizing height over bore.

 

[*Tavman*]

Good read. I'm thinking I probably need to go a little lower than what I'm currently using.

 

[Killer Spade 13]

Scope tube diameter + bolt diameter divided by two plus distance between bottom of scope tube and top of bolt.

 

[Drew9299]

Well said

 

[Okiegunner]

How close to the barrel is too close? I know every barrel moves when you fire a round. I have a 1.5 tall spuhr right now and have .4 between my barrel and sunshade. Thinking of getting the 1.18 tall one which would leave me with .08 between. Is that too close?

 

[mdmp5]

0.08 is fine from what I can see. I've have closer than that. I just amended the original post to include calculation for base and/or mount elevation

 

[JePhyllis]

Just adding some new info. Some brand rings have different measurements. For example, Burris uses the distance between the ring base and the rail mount base as their height. So take care when you purchase a new brand product.

 

[Rick7353]

Re: Ring Height Questions

You also need to take into account the barrel size and the height of the action to the barrel.

To make it easy,

40mm or less - low rings all the time
50mm obj - low rings on < 5 contour
Medium rings > #5 and up (strait barrel get med high)
56mm obj Medium on < 5 contour (sometimes med high)
Medium high on sendero contour
High on >7 contour

34mm...
50mm objective - lows will work all the time
56mm objective - lows < sendero or #5 contour Sometimes lows will fit number 7 contour barrels, but it depends on how long the shank is after the smith installed it.
Highs for sure anything larger than #7

This is assuming our ring height and our rail height. Also using buttler creek caps. YMMV...

Thanks for that. I use your rings and they are great.

 

[Hemiphil]

This what I use, very simple and intuitive

http://www.mil-rad.com/scope_ring_calculator

 

[mildot 72]

hi glen

 

[LunaCustomGuns]

Excellent advice, thanks

 

[Sainte70]

http://www.mil-rad.com/scope_ring_calculator

 

[Sinocopa]

Great information!

 

[OH_FAL]

I know lack of clearance is the penalty for getting rings too short, but what happens if we get rings higher than necessary?

 

[Sainte70]

I know lack of clearance is the penalty for getting rings too short, but what happens if we get rings higher than necessary?

You end up holding your neck all the way back/up at a very awkward and painful angle to be able to shoulder the rifle and see thru the scope at the same time.

I shouldered my brothers r700 this weekend and experienced this. It was not fun.

When you get behind your rifle, everything should be set up where it all falls in line naturally to fit your body with little or no adjustment. That is just my uneducated, inexperienced opinion when it comes to long guns though.

 

[Full Otto Tactical]

Great thread!

 

[Sainte70]

The only problem with the height calculator that I see is that it does not take into account the length of the scope, especially if it has a long sunshade installed.

 

[Archer01]

Guys,

Lately, on average of about 1 per day, I have seen quite a few posts (mostly from newbies) regarding questions about what ring height should be used. They usually request pics for comparison. For all new guys, there is a systematic way of calculating ring height that doesn't require more than a simple elementary school ruler. You measure 3 things:
1. the height of the front of your base/rail from the barrel
2. the height of your rings from the top of the rail to centerline
3. the outside diameter of the bell of the scope (not the size of the objective lens)

Here is the equation:

[rail height + ring height] - [bell diameter x 0.5]

If the value is positive, then your bell will clear the barrel. Ideally, you want that bell to be about 1/4" or less over the barrel. This will give you a tight cheek weld. Be sure to account for Butler Creek caps if you intend on using them.

If you are using a 40mm objective, then you can use the lowest rings and bases available, as the bell will certainly clear the barrel with no problem. i.e. don't worry if the bell ends up being higher than 1/4" over the barrel.

Hope this helps.

mike

Just another note. If you are using a scope base and/or mount/rings that have built in elevation, that may have to be accounted for in the case of very small clearance. To calculate this, we need to know the amount of elevation built into the mount/rings and/ or base, and the length from the end of the scope base to the end of the scope bell. Convert MOA into degrees, and then the equation is:

Tan ? x length

For example, if you are using a 20 MOA base, and the distance from the edge of the scope base to the end of the bell is 5". 20 MOA = 0.333 degrees, so:

Tan 0.333 x 5 = 0.029"

This means that you need an extra 0.029" of clearance in addition to the calculation above
Mr. Calvin Wyche w /All Credentials &Entitlements I

 

[Archer01]

I am-Mr. Calvin Wyche w/All Credentials & Entitlements

 

[DJL2]

If anyone might find it useful, I just measured the objective OD on my SIG Tango6 4-24x50mm. OD comes out to 2.280 inches (average of five measurements, taking into account the “bell” is not perfectly round). That’s 58mm, as near as makes no difference.

Centerline height / radius: 1.14 inches, 29mm.

 

[WheelieJustin]

What would you put into the calculator for a Burris 25moa base on a Sendero barrel? That is the part that is a little more guesswork. Have a Steiner 4-16x56 the bell is 64.7mm. Have the choice of rings of 1 inch or 1.25. The 1 inch will be really close. Should probably get the 1.25? Whats a .3 gap.