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Rifle Scopes Check my math- AI mount for Hensoldt 4-16 ff

bm11

Gunny Sergeant
Full Member
Minuteman
Jun 18, 2010
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Maine
Ok,

I might be doing my math wrong, but here is a "situation" I have run into, and wanted to check it with you guys before I go unnecessarily buy a mount: the guy I just traded with had the Hensoldt 4-16x56 ff mounted in a 45 moa AI mount. He had 5.5 mils of downward travel left on a 100 yard zero with that mount. That being said, I need to come up 27 moa, which is about 8.1 mils, leaving me with 12.6 mils of downward travel. If this scope has 15 mils of total elevation, I only have 2.4 left to go up.

This doesn't make sense to me, which is why I posted this, anyone with personal experience, please chime in.

-Bob
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bm11</div><div class="ubbcode-body">Ok,

I might be doing my math wrong, but here is a "situation" I have run into, and wanted to check it with you guys before I go unnecessarily buy a mount: the guy I just traded with had the Hensoldt 4-16x56 ff mounted in a 45 moa AI mount. He had 5.5 mils of downward travel left on a 100 yard zero with that mount. That being said, I need to come up 27 moa, which is about 8.1 mils, leaving me with 12.6 mils of downward travel. If this scope has 15 mils of total elevation, I only have 2.4 left to go up.

This doesn't make sense to me, which is why I posted this, anyone with personal experience, please chime in.

-Bob</div></div> Your situation is totally unclear. First of all, stop converting from mils to MOA. Is your scope in mils or moa? let's pick a unit and stick with it.

Are you taking this scope and mounting it to a flat rail and now your new 100yd zero is 8.1 mils from the bottom?

Why do you need to come up 8.1 mils? And if you came up 8.1 mils and the scope only has 15 mils of elevation, why would that leave you with 12.6 mils of travel?
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

Here's the deal...

I assume you're shooting the AIAW with the flat picatinny base and that the rail is parallel to the bore. Now, if your scope has 15mils of adjustment and you grab some standard rings and mount it up, you would (theoretically) have roughly 7.5 mils of adjustment either way.

Now let's make another assumption... Let's assume you want to make it to at least 1000yds and that you need 9.5 mils to get there. With the normal rings you'd have to hold-over by 2 mils since you ran out of adjustment at 7.5 mils.

If you bought AI's 18moa base that would cant the bell of your scope downward about 5 mils giving you a theoretical 12.5 mils of elevation to play with... Enough to get you to 1000 and some change.
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

First off I think you are confused. So let me share my insight.
I run a 4-16 ff on my Badger with 40 moa worth of cant. It gives me .5 mils before I bottom out, so in turn it gives me 22.5 mils of elevation. And that is with a 100 meter zero. I am pretty sure that 45 moa would be way to much for the 4-16ff. It would work with the 3-12 ff because it has more elevation to work with.

Cheers,
DM
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

If you can get around the magical number of 35-40 MOA worth of cant you will be golden, Heck even the 28 MOA base will do what you need it to do and leave you plenty of elevation
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: brasscow</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bm11</div><div class="ubbcode-body">Ok,

I might be doing my math wrong, but here is a "situation" I have run into, and wanted to check it with you guys before I go unnecessarily buy a mount: the guy I just traded with had the Hensoldt 4-16x56 ff mounted in a 45 moa AI mount. He had 5.5 mils of downward travel left on a 100 yard zero with that mount. That being said, I need to come up 27 moa, which is about 8.1 mils, leaving me with 12.6 mils of downward travel. If this scope has 15 mils of total elevation, I only have 2.4 left to go up.

This doesn't make sense to me, which is why I posted this, anyone with personal experience, please chime in.

-Bob</div></div> Your situation is totally unclear. First of all, stop converting from mils to MOA. Is your scope in mils or moa? let's pick a unit and stick with it.

Are you taking this scope and mounting it to a flat rail and now your new 100yd zero is 8.1 mils from the bottom?

Why do you need to come up 8.1 mils? And if you came up 8.1 mils and the scope only has 15 mils of elevation, why would that leave you with 12.6 mils of travel? </div></div>I was converting moa to mils because the AI mounts are in MOA. The previous owner of this scope had it mounted in a 45moa base, which left 5.5 mils below zero. The math was used to determine roughly how much I would have to come up to be on paper, and at that point I determined that I wouldn't be left with much travel.
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

From the answers I am receiving, it would seem that the 28 moa base is the answer, OR a Spuhr 30 moa base.

Was I wrong about the 15 mils of elevation? The specs on the Hudisco site state a total elevation travel of 150cm/100m. Which by my math is 15 mils.
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

In looking on the Sport Optics site, according to their specs there is more like 22.4 mils of total travel. So I would still need a 28 moa base, but I am not as crippled by the 18 moa as I thought.
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

22.4 Mils of total travel on a flat base yields:
11.2 Mils of UP. (11.2 Mils = 36 MOA)
11.2 Mils of DN (11.2 Mils = 36 MOA)

If you put a 20MOA (20MOA = 5.8 Mils) base on it you will have
17 Mils of UP (58MOA of UP)
5.4 Mils of DN

1 Mil = 3.44 MOA

Although you can shoot out to 1000 yards with a 0 MOA base, most of us are putting a 20MOA base on because it doesn't hurt and might help. Nothing more frustrating than running out of scope adjustment.
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

^^^I agree. What bothered me is that the previous owner of this scope had it on a 45 moa base and still had 5.5 mils of down, suggesting that there wouldn't be that much more up left over. But we'll see tomorrow when I get it in.

He (the previous owner) does make a good point though- using the 45moa base does add a makeshift zero stop, which is kind of nice.
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

Novice question: When you say a base is "canted" does that mean it's actually sloped downward? From reading articles on cant errors when mounting scopes (reticules not squared with turrets) it looks like cant is when the rifle is rotated out of the vertical plane that goes through the scope and bore? So does the base intentionally cant the scope (which to me seems completely wrong) or does it have a slight decline?

Sorry for the OT question but I want to make sure I understand the full meaning of cant.
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Aubie</div><div class="ubbcode-body">Novice question: When you say a base is "canted" does that mean it's actually sloped downward? From reading articles on cant errors when mounting scopes (reticules not squared with turrets) it looks like cant is when the rifle is rotated out of the vertical plane that goes through the scope and bore? So does the base intentionally cant the scope (which to me seems completely wrong) or does it have a slight decline?

Sorry for the OT question but I want to make sure I understand the full meaning of cant.</div></div>

You are confusing side to side cant with front to back cant which is necessary to use the elevation in most scopes.
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

This is just too much math for me.....

I have my 4-16 on a 40moa base, have .6 mil down, lots of mils up.

I would be very surprised if you could get a 100 yard zero with the 45moa base.
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jasonk</div><div class="ubbcode-body">This is just too much math for me.....

I have my 4-16 on a 40moa base, have .6 mil down, lots of mils up.

I would be very surprised if you could get a 100 yard zero with the 45moa base. </div></div>It was Mo_Zam_Beek who I traded with, and I think he knows what he's talking about. That being said- the AI mounts aren't labeled (at least mine isn't) and maybe it was really a 28 moa base, which would explain why it still has 5.5 mils of downward travel after being zeroed at 100 yards.
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

Just confirmed with him for sure it was a 45 moa mount that he had it in. In any case, the scope comes in tomorrow, with luck before my range session. I'll let you guys know how much I have left with my 18 moa mount.
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

Just because it has 22 mils of total elevation doesnt always mean 1/2 is up and 1/2 is down. Some mfgs make it so there is more up than down. You really never know until you mount it and try it.

Almost any gunsmith can make a 20moa base into one of a different moa. Just have him mil it off.

Id get a 20 moa base and try it. It should work. If it doesnt take the base and gun to a smith and have him customize the base.
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">what caliber did he have it on ? </div></div>Not positive. Assumed .308 but it was an AW, so it could have been a few calibers at least.
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

here you go.....

2jc64hg.jpg
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

Ended up taking 7.1 mils of elevation from the current zero to get to a 100 yard zero for me. Lowlight- it WAS a 24" barreled AW in .308.

I was in a rush to get it zero'd and my new semi rig zeroed, so I didn't even have a chance to see how much elevation is left.

Nice scope.
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

Cool, glad you got it.

FWIW - I had the same question and PM'd Deadly about which mount. He told me 45 MOA. Worked for me.

Good luck.

bm11 - enjoy your new wonder optic.



Good luck
 
Re: Check my math- AI mount for Hensoldt 4-16 ff

To update this because I said I would- I have just over 15 mils of elevation left using an 18 moa AI mount. So I don't think I need another mount unless I want a quasi "zero stop" mount (don't think I need it, would really need to be not paying attention to lose it with this many mils per revolution.