30 MOA Base Question

[TexT-Rex]

I have a vortex viper PST Gen II 5-25x50 with Mrad reticle sitting on a 6.5 Creedmoor bolt gun, secured to a 20 MOA base. The range I shoot at has a 1-mi target. I have a 100-yard zero and 18 Mrad of up adjust or 180-clicks up. I'd like to move to a 30 MOA base (Scope only has 70 MOA total elevation adjust so can't manage a 40 MOA base). I can see where 10 MOA = 2.908 or ~2.9 Mrad. My question for those experienced in such things: Would the 30 (vs 20) MOA base yield an actual 2.9 Mrad of up adjustment to my current setup (making is 20.9 vs 18 Mrad), or are there other factors that make that something different or is it possible to predict without verifying after zeroing with the 30 MOA base?

 

[kopcicle]

Axeon Optics Second Zero Eliminates holdover, guesswork, and extensive ballistics knowledge. | Axeon Optics

Pair the Axeon Second Zero with any optic to aim center at long range with no holdover. The easy bullet drop solution for long distance shooting.

www.axeonoptics.com

Charlie TARAC

tacomhq.com

So here's the advantage of using a YUUUUGE amount of "wedge" for extreme long distance shooting.
You regain some of your windage. As you get into the top of the tube your available windage decreases.
There are other optical difficulties but reduced windage availability is the most obvious.

Some of this loss of windage adjustment can be addressed by 30 and 34mm tubes. So , $$$$
You are already at 30mm in a good bit of glass.

I'm wondering if you aren't looking at a bit of a bridge too far. I may be eating chili and beans after midnight but but isn't the 6.5 CM about done [subsonic] at 1500 # 147gr ?

From memory, at around 2850FPS and 147gr, and transonic at 1500-1700 yards,, can be done with an elevation at 19 mils? Then again I could be stoned or stupid. This was years ago and a 6.5 x 55 AI experiment in a 24" barrel and 130-140gr whatever was available.

I just don't see where anything more than a 20 MOA wedge is needed.

Change my mind

 

[Matches Malone]

I have a vortex viper PST Gen II 5-25x50 with Mrad reticle sitting on a 6.5 Creedmoor bolt gun, secured to a 20 MOA base. The range I shoot at has a 1-mi target. I have a 100-yard zero and 18 Mrad of up adjust or 180-clicks up. I'd like to move to a 30 MOA base (Scope only has 70 MOA total elevation adjust so can't manage a 40 MOA base). I can see where 10 MOA = 2.908 or ~2.9 Mrad. My question for those experienced in such things: Would the 30 (vs 20) MOA base yield an actual 2.9 Mrad of up adjustment to my current setup (making is 20.9 vs 18 Mrad), or are there other factors that make that something different or is it possible to predict without verifying after zeroing with the 30 MOA base?

Mathematically in a perfect world, it’s suppose to give you the +2.9.

Where you end up on your zero, the manufacturing process the turret/erector, rounding errors, and the accuracy of the mounts machining will decide if you get a actual 2.9 more or maybe some other arbitrary number like 2.4.

 

[TexT-Rex]

Mathematically in a perfect world, it’s suppose to give you the +2.9.

Where you end up on your zero, the manufacturing process the turret/erector, rounding errors, and the accuracy of the mounts machining will decide if you get a actual 2.9 more or maybe some other arbitrary number like 2.4.

Thanks. That's what I was looking for, that I had the theory or theoretical correct. Of course there is no substitute for real world data. Appreciate the response!

 

[TexT-Rex]

Axeon Optics Second Zero Eliminates holdover, guesswork, and extensive ballistics knowledge. | Axeon Optics

Pair the Axeon Second Zero with any optic to aim center at long range with no holdover. The easy bullet drop solution for long distance shooting.

www.axeonoptics.com

Charlie TARAC

tacomhq.com

So here's the advantage of using a YUUUUGE amount of "wedge" for extreme long distance shooting.
You regain some of your windage. As you get into the top of the tube your available windage decreases.
There are other optical difficulties but reduced windage availability is the most obvious.

Some of this loss of windage adjustment can be addressed by 30 and 34mm tubes. So , $$$$
You are already at 30mm in a good bit of glass.

I'm wondering if you aren't looking at a bit of a bridge too far. I may be eating chili and beans after midnight but but isn't the 6.5 CM about done [subsonic] at 1500 # 147gr ?

From memory, at around 2850FPS and 147gr, and transonic at 1500-1700 yards,, can be done with an elevation at 19 mils? Then again I could be stoned or stupid. This was years ago and a 6.5 x 55 AI experiment in a 24" barrel and 130-140gr whatever was available.

I just don't see where anything more than a 20 MOA wedge is needed.

Change my mind

Thanks for the reply. Not going to try to change your mind because you make sense. The range has targets out to 1,500 yards which the 6.5 CM will do for. I am hand loading 153.5gr and 156gr Bergers at 2800 FPS so your numbers above aren't far off at all. I'd just like to hit that 1750-yard target a couple times and then stick with the 1500 and in ones. Thanks again!