Jump to content
308AR.com Community
  • Visit Aero Precision
  • Visit Brownells
  • Visit EuroOptic
  • Visit Site
  • Visit Beachin Tactical
  • Visit Rainier Arms
  • Visit Ballistic Advantage
  • Visit Palmetto State Armory
  • Visit Cabelas
  • Visit Sportsmans Guide

Measuring scope height?


Recommended Posts

Trying to get an approximate height over bore measurement on my AR10 & RPR. Any tips or simple way?

For AR 10:

Barrel is .80"...... 1/2 would be .40"

Scope tube = 34mm.... 1/2   .66"

Mount height = 1.5"

 

What else do I need?

Would I be close enough just measuring from center of bolt to center of scope tube?

Edited by Lonewolf McQuade
Link to comment
Share on other sites

Is this for a ballistic calculator or something? I generally just eyeball it with a measuring tape. Half way through the barrel to halfway through the scope tube. Should be plenty close. 

 

If you are trying to measure for a specific scope mount, I usually mock up spacers with cardboard or something to make sure my measurements translate over to real world usage. 

 

Link to comment
Share on other sites

On 1/2/2022 at 1:20 AM, blue109 said:

Is this for a ballistic calculator or something? I generally just eyeball it with a measuring tape. Half way through the barrel to halfway through the scope tube. Should be plenty close. 

 

If you are trying to measure for a specific scope mount, I usually mock up spacers with cardboard or something to make sure my measurements translate over to real world usage. 

 

Thank you. 

I was to comparing ballistic app against my notes. I got to playing with different variables & noticed minimal to modest differences depending upon scope height. 

Link to comment
Share on other sites

The parallax when you are way over bore really makes a difference at long range. I try to get all my scopes as low as possible while still being comfortable. Lots of measuring and searching different manufacturers specs. 

PXL_20211114_172337970~2.jpg

Link to comment
Share on other sites

On 1/2/2022 at 3:05 AM, blue109 said:

The parallax when you are way over bore really makes a difference at long range. I try to get all my scopes as low as possible while still being comfortable. Lots of measuring and searching different manufacturers specs. 

PXL_20211114_172337970~2.jpg

Try to keep mine low also. 

Link to comment
Share on other sites

Don't make this complicated.  Don't complicate shiit with complicated shiit.  Height over bore on ARs is usually 2.5". It can be a tenth higher or lower, but it's generally right there at 2.5".

Bolt guns are usually 1.5".

If you want to get crazy, and really measure it, just measure from the center of the BCG to the center of the scope.  That's your Height Over Bore.  The center of your BCG is also the center of your barrel bore.  Can't go wrong with that.   

Link to comment
Share on other sites

  • 6 months later...

I'm currently trying to determine what mount to use for a 3-15x56mm w/ a 30mm tube.  Leaning towards trying the integrated Leupold Mark AR 30mm.  I currently use the 1" version of this mount with a 1" tube 3-9 x 50mm on another AR 10 and there is about 6-10 mm of clearance - hard to measure accurately in the location of smallest clearance. Also, haven't figured out if the 1" (25.4mm versus 30mm scope/mount diameter) will be critical.  Want it as low as possible - but don't it rubbing and like to use lens caps.

Wondering what mounts others have used and like for similarly sized scopes.

Link to comment
Share on other sites

I have an Athlon BTR Argos gen 2

8-34x56 on my 6mm ARC. I used the Athlon 1 piece mount w/20 MOA built in. It's a 30 mm mount. Less than a 1/4" between the rail and lense cap.

I have a couple of the Athlon one piece mounts and they hold up well.

IMG_20220724_153249.jpg

IMG_20220724_153228.jpg

Link to comment
Share on other sites

^^^  I'm running that exact same mount on the 12.5" 6 ARC gun, and love it on there.  44mm objective lens clears well, and keeps it pretty low.  My go-to mount to keep scopes as low as possible is the LaRue LT-158.  That mount is available either in 1" or 30mm, has 10 MOA built into it, and has a centerheight (above the mounting surface) of 1.46".  Most mounts are 1.5" above the mounting surface.  I've used that mount on alot of my guns, and it's close with 50mm objectives, but still clears them and they don't touch the rail, even with Butler Creek flip-up covers on.

Edited by 98Z5V
Link to comment
Share on other sites

Thanks for the input! I'll definitely look at the Athlon & LaRue mounts.  I've also sent a question into Leupold Customer service.  See if and how quickly they respond in the post-Covid world of scarce employees.  And, I saw where Midway currently has some blem VX6 - 2-12x42 for a very decent discount. That's a damn fine hunting scope at $500 off. Trying to hold off on the scope purchase until the bank account has recovered from the rifle purchase (DD5v3). Already have a perfectly good rig setup for this Fall's hunting season.

Edited by MtnMike
typo
Link to comment
Share on other sites

For the record - and because I think good customer service should be commended - Leupold got back to me in less than than 1 business day and informed me that the mount in question would work with the scope in question with 0.15" clearance.  SO their support is still up and running like it used to!

I did look at those LaRue mounts. Love their MBT-2 triggers. But their mounts are kind of pricey.  Especially considering I rarely, if ever, remove a scope I'm happy with. $324 - That's a lot of bullets I can be shooting instead of biting!

Link to comment
Share on other sites

That LT-111 is 1.535" above the mounting surface, and it's just not ideal for a semi-auto, because of that.  It also doesn't get the scope forward, which you want on a 1-piece mount on an AR.  I wouldn't use that for an AR.  They say it's the perfect mount for the OBR - cool.  I get it.  It has zero MOA built in, because the OBR has 20 MOA built right in to the top of the gun.  There are other mounts they make that are better, for ARs.

The 158 isn't that much - it's $258 now. 

https://www.larue.com/products/larue-tactical-spr-s-mount-lt158/

10 MOA built in, 1.46" height over mounting surface, and you'll be very hard pressed to find a cantilever mount for an AR that will get lower than that, and still clear big objective lenses.  Don't count it out.  Buy once, cry once.

It used to be $210, and if you selected Legacy VFZ Mount, it took $50 off, and you'd get it for $160.    You can thank ONE GUY for that...

I Did That Biden Stickers, That's All Me I Did That-Biden Sticker Funny Decals (C, 100PCS)

Link to comment
Share on other sites

OK. Confessing my ignorance.  What the difference between a scope mount with 20MOA vs 10MOA?  I very rarely shoot at distances more than 150 yards.  Pretty sure I read somewhere the Leupold has 20MOA built in.

Also, in their defense the Leupold Mark AR mounts are made in the US and the one on my WW has been bullet-proof and never moved at all.  They're held on with 5 bolts.

Don't see any current discount for the VFZ mount at LaRue.  The Leupold is currently $77 at Midway.

2 pieces of info I don't have:

(1) Exactly -the height over mounting surface for the 30mm Leupold - not sure how this is measured and is that the same thing as ring height? Top rail to the center of the scope on my 1" version on my WW measures right at 1.5".  Leupold specs the ring height for the 30mm version at 1.4".  I've always been told that you want to go as low as possible - but obviously your objective lens needs to clear.

(2) Anyone have any idea of the weight of the LaRue in its QD and/or VFZ configurations?  Don't see this info on their webpage. Leupold is 5.8 oz. I try to keep my rifles and gear as light as possible w/o sacrificing ruggedness.  QD does have some appeal. It might be nice to be able to use the same scope on multiple rifles.

Now to sneak the newest black rifle into the house from the truck while the wife is still asleep ... once inside it should blend in unnoticed! 

Link to comment
Share on other sites

98 is correct the 111 has no moa in it the OBr has 20 in the rail i use mine on both LR 308 and a bolt gun mostly on the bolt gun that rail has 20 MOA built in it

To measure scope height measure from center of bore to center of scope rings that is the value you put in your ballistic solver.....

How low you mount your scope on any rifle has as much to do with what your stock is like and what is comfortable for you to shoot, if your scope is 1/8th over the bore which is low and you can not get your eye aligned with it to shoot properly then that mount is to low so you will have to figure out your scope /stock /and how you mount the rifle to get proper scope height... your mileage may very  .......

Edited by Magwa
Link to comment
Share on other sites

Isn't minute angle of the mount is the amount of vertical angle of change, in minutes , between the bore of the rifle and the bore of the scope?

The more minute of angle mounting drops the line of sight of the scope to accommodate the drop of the bullet for long distance shooting. Right? or wrong?

https://www.nssf.org/shooting/minute-angle-moa/

Edited by mrmackc
Link to comment
Share on other sites

So,  a 20 MOA mount tilts the scope down (to raise the barrel angle up) twice as much as a 10 MOA? If I am understanding correctly.

I actually started out as a math major decades ago ... obviously killed off those brains cells over the decades.

Link to comment
Share on other sites

9 hours ago, MtnMike said:

So,  a 20 MOA mount tilts the scope down (to raise the barrel angle up) twice as much as a 10 MOA? If I am understanding correctly.

I actually started out as a math major decades ago ... obviously killed off those brains cells over the decades.

This is correct math. ^^^

Link to comment
Share on other sites

17 hours ago, MtnMike said:

Don't see any current discount for the VFZ mount at LaRue. 

Well, you certainly blew Reading Comprehension then.  Selective Reading is what you did, and if you really looked at what I said, I told you it was $258 now.  BEFORE I told you that JoeBama has fucked everything up, and it's now $258. That's "inflation" and "supply chain delay" that caused this.   It USED TO BE $210, and IF (BEFORE) you didn't want the QD levers, you got it $50 less, at $160.  I thought I was pretty clear on that, but apparently now, I wasn't and must be more clear.  Reading Comprehension, my man.  Stick with it.  Read UP there if you think I'm BSing you.  I stated it right.  You didn't read it right, and got all wrapped around the axle.

On 7/25/2022 at 9:04 PM, 98Z5V said:

It used to be $210, and if you selected Legacy VFZ Mount, it took $50 off, and you'd get it for $160.    You can thank ONE GUY for that...

 

On 7/25/2022 at 9:04 PM, 98Z5V said:

The 158 isn't that much - it's $258 now. 

 

Edited by 98Z5V
Link to comment
Share on other sites

@98Z5V No worries my friend. I read you right.  Just thought maybe I was currently missing a price differential on the VFZ vs the QD mount.

What I really want you to do, because I'm a selfish egotistical bastard, is to disassemble your gun and weigh the 158 mount - (even though there's a 90% chance I'll still get the the Leupold - cause I'm bent that way and it appears to be slightly lower).  But I would never actually expect you to do that. I think I'm the only one who anally weighs his components.

My biggest problem with the Leupold Vx5 3-15x56 is it weighs in at 22.2 oz., which is heavy by my standards.  I'm constantly face the dilemma when choosing scopes of going with the larger objective lens (which I Iike for low light hunting) versus the added weight they bring.  The Vx5 3-15xx44 weighs 19.7 oz. And the Vx6 2-12x42 weighs in at 19.9 oz and includes the very nice Alumina magnetic lens caps.

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...