15 MOA scope base for one mile?

Jon Conley

JMC1
Minuteman
Jun 12, 2019
15
4
I’m trying to get setup for a mile and I’m not sure about my scope base.
The rifle‘s an AR-30 and came with a 15 min scope base. I’ve looked around and called Armalite, it doesn’t look like finding a different base will be easy. I’m trying to find out if the 15 minute base will work.
My scope is a Viper HST and it has 65 MOA in it.
Strelok says I need 227 clicks or 57 MOA. Am I thinking about this correctly? I need 57 MOA and I have 65 in the scope, so that gives me 32.5 mins of vertical plus the 15 mins in the base. That gives me 47.5 MOA and I'm left 10mins short if things ended up prefect..
Well I guess it depends on how many clicks I have left once I‘m sighted in. I’d like to sight in at 100 yd.
I’ve never shot past 1,000 yd so I’m just trying to get this right in my mind.

Thoughts?

AR-30 in 338 Lapua
300 gr Berger OTM @ 2880 fps
Vortex Viper HS-T 6-24
 
Last edited:

AZgeek

Private
PX Member
Minuteman
Sep 30, 2014
549
209
I went with a 45moa base on my 7mm rem mag for this same application distance, but yes 30moa will get you there. Make sure your rings are high enough to clear the front objective from touching the barrel due to the additional cant angle.
 

addertooth

Sergeant of the Hide
PX Member
Minuteman
Dec 21, 2020
118
194
South East Arizona
I went with a 45moa base on my 7mm rem mag for this same application distance, but yes 30moa will get you there. Make sure your rings are high enough to clear the front objective from touching the barrel due to the additional cant angle.
I am a bit confused. With a 20 MOA mount, wouldn't the scope body start pointing more upwards, and you have to adjust your turrets downwards (towards the minimum), to leave you the maximum elevation adjustment to go UP? This would move the front lens of the scope further away from the barrel, wouldn't it? Relative to the front (objective) lens, the rear (ocular) lens would be tilted closer.

I may be wrong here, and if I am, square me away.
 

Steel head

Feral kitten
PX Member
Minuteman
  • Aug 3, 2014
    12,931
    33,548
    Washington
    I am a bit confused. With a 20 MOA mount, wouldn't the scope body start pointing more upwards, and you have to adjust your turrets downwards (towards the minimum), to leave you the maximum elevation adjustment to go UP? This would move the front lens of the scope further away from the barrel, wouldn't it? Relative to the front (objective) lens, the rear (ocular) lens would be tilted closer.

    I may be wrong here, and if I am, square me away.
    Bases with offset pull the front Down and rear up.
    Like a proper Instagram pose.
    940D2B6A-B77E-4FB3-9E98-CAAA836017DC.jpeg
     

    Newbie2020

    Mmmyeah...whatever
    PX Member
    PX Member
    Minuteman
    Jan 10, 2020
    1,232
    944
    Amarillo
    I like my Burris xtr rings w interchangeable Teflon elevation inserts. It’s super flexible for different circumstances.
     

    addertooth

    Sergeant of the Hide
    PX Member
    Minuteman
    Dec 21, 2020
    118
    194
    South East Arizona
    I am a bit confused. With a 20 MOA mount, wouldn't the scope body start pointing more upwards, and you have to adjust your turrets downwards (towards the minimum), to leave you the maximum elevation adjustment to go UP? This would move the front lens of the scope further away from the barrel, wouldn't it? Relative to the front (objective) lens, the rear (ocular) lens would be tilted closer.

    I may be wrong here, and if I am, square me away.
    Thanks... I just had to look at a graphic from Warne to square me away. I got the whole look versus strike thing backwards.
     

    AZgeek

    Private
    PX Member
    Minuteman
    Sep 30, 2014
    549
    209
    For this platform, he could also just keep what he has and use an ERA-tac adjustable mount. Pricey but they provide up to like 70 MOA.
     

    Jon Conley

    JMC1
    Minuteman
    Jun 12, 2019
    15
    4
    As I was saying, I talked with Armalite. There are no 20MOA bases available for my rifle. It has it's own custom base holes and aftermarket just aren't made any longer.
     

    Jon Conley

    JMC1
    Minuteman
    Jun 12, 2019
    15
    4
    I do have this old 20min riser. It's made by UTG Leapers, so I'm sure quality is low and I hate the thought of it being on my rifle. The thing is it seems to be a solid chunk of medal, it's heavy but with a rifle that's already heavy it doesn't matter.
    So now if I use this I will have the 20 MOA and the 15 that came on the action. Do you think I'll still be able to sight in at 100yds with 35mins in my base?

    unnamed (1).jpg
     
    • Like
    Reactions: Slides

    badassgunworks

    Sergeant of the Hide
    PX Member
    Minuteman
    Dec 25, 2018
    362
    283
    The way you calculate what you need to utilize the entire scope travel is take the overall travel from top to bottom in your scope and divide that in half so if your scope has 60 MOA travel you need us 30 MOA base your scope comes reticle centered otherwise you have the same amount of travel up as you do down the total travel from top to bottom is the total travel that the scope has since a parallel mount will only allow you to utilize half of the overall travel you need a can't base to utilize that which is below parallel
     
    • Like
    Reactions: Steel head

    Steel head

    Feral kitten
    PX Member
    Minuteman
  • Aug 3, 2014
    12,931
    33,548
    Washington
    I do have this old 20min riser. It's made by UTG Leapers, so I'm sure quality is low and I hate the thought of it being on my rifle. The thing is it seems to be a solid chunk of medal, it's heavy but with a rifle that's already heavy it doesn't matter.
    So now if I use this I will have the 20 MOA and the 15 that came on the action. Do you think I'll still be able to sight in at 100yds with 35mins in my base?

    View attachment 7561255
    35 moa won’t zero at 100 with that scope probably.
    Also you’ll find at the upper end of travel shading appears and image starts to suffer.
     

    Steel head

    Feral kitten
    PX Member
    Minuteman
  • Aug 3, 2014
    12,931
    33,548
    Washington
    The way you calculate what you need to utilize the entire scope travel is take the overall travel from top to bottom in your scope and divide that in half so if your scope has 60 MOA travel you need us 30 MOA base your scope comes reticle centered otherwise you have the same amount of travel up as you do down the total travel from top to bottom is the total travel that the scope has since a parallel mount will only allow you to utilize half of the overall travel you need a can't base to utilize that which is below parallel
    That’s how I figure out needed elevation.
     

    Jon Conley

    JMC1
    Minuteman
    Jun 12, 2019
    15
    4
    30 moa base will zero at 100 yards though
    I really wanted to go with 100 yards zero to make my Streloak Data as perfect as possible.
    what’s the general consensus of everyone, do most people try to get sighted in at 100 or do you stretch it out to 200yd for the problem I’m having?
     

    Arcticshooter

    Private
    Minuteman
    Jan 13, 2012
    23
    4
    52
    Alaska
    I just set up one of mine with the Era-Tac adjustable 0-20 MRAD mount (0-70 MOA). I went with the QD levers too.
    Not cheap, but they did a beautiful job. I haven't had a chance to zero it yet, just waiting for a break in the work schedule.
    With the 338LP you could really put those 70MOA to use.
    Lastly, stretching your rifle WAY out there, while retaining the use of your 100yd zero is supposed to be pretty easy with this system.
     

    Jon Conley

    JMC1
    Minuteman
    Jun 12, 2019
    15
    4
    I just set up one of mine with the Era-Tac adjustable 0-20 MRAD mount (0-70 MOA). I went with the QD levers too.
    Not cheap, but they did a beautiful job. I haven't had a chance to zero it yet, just waiting for a break in the work schedule.
    With the 338LP you could really put those 70MOA to use.
    Lastly, stretching your rifle WAY out there, while retaining the use of your 100yd zero is supposed to be pretty easy with this system.
    Thanks..
     

    AZgeek

    Private
    PX Member
    Minuteman
    Sep 30, 2014
    549
    209
    Yup. The Era-Tac system works really well. Have one on my Barrett M82A1 and was able to get the full 120 MOA out of my ATACR scope. Again proper ring height (to take advantage its full 70 moa capability with your scope) is required.
     
    • Like
    Reactions: Arcticshooter