Rifle Scopes Down adjustment with 20moa base necessary?

[ruth]

Guys,

I would like to know if it is necessary for a scope to have any down adjustment left after mounting on a 20 moa base or if the goal with any canted base is to acheive as much up elevation without worrying about down adjustments remaining?

 

[Rob01]

Re: Down adjustment with 20moa base necessary?

The goal is to have 20 MOA more up elevation. How much down you have after zeroing will depend on how much total internal MOA the scope had to begin with and how much windage you used to zero as a large amount of windage can cut into the amount of elevation travel.

 

[ruth]

Re: Down adjustment with 20moa base necessary?

Rob01

Thanks, but do you want "any" down elevation left when you mount a 20 moa base?

 

[MontanaMarine]

Re: Down adjustment with 20moa base necessary?

Well if you have it fully bottomed out you are putting max compression on the erector spring(s).

I'd prefer to have 5 moa or so left at the bottom.

 

[Rob01]

Re: Down adjustment with 20moa base necessary?

I would want some so I am not completely bottomed out but there's really no use for it with a 100 yard zero. How much do you have?

 

[ruth]

Re: Down adjustment with 20moa base necessary?

I have 4.25moa down adjustment left.

 

[Rob01]

Re: Down adjustment with 20moa base necessary?

You should be fine.

 

[McLarenross]

Re: Down adjustment with 20moa base necessary?

On my Rem 700 with a 20MOA base and a 12x44 WOTAC I only have 1 mil down left. Kinda works like a Zero Stop if you think about it.

 

[SuckitTrebek]

Re: Down adjustment with 20moa base necessary?

The real question here is how the hell you do 25 years in the Corps and only deploy once!! Now there is a trick most don't learn.

 

[MontanaMarine]

Re: Down adjustment with 20moa base necessary?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: YourMotherTrebek</div><div class="ubbcode-body">The real question here is how the hell you do 25 years in the Corps and only deploy once!! Now there is a trick most don't learn. </div></div>

No trick. I haven't been back to mil-sigs to update my shit. Stars weren't in the program when I created it, and since i'm on dial-up, I have avatars and sigs turned off.

 

[SuckitTrebek]

Re: Down adjustment with 20moa base necessary?

two deployments, jesus. just messing with you master guns

 

[Timo Turl]

Re: Down adjustment with 20moa base necessary?

amount of downward adjustment needed will depend on what range you zero it to.

 

[MontanaMarine]

Re: Down adjustment with 20moa base necessary?

I spent about 8 years overseas, out of 25.

Earned over 48 months of hostile fire pay, imminent danger pay, combat pay, etc, in El Salvador, Croatia, Egypt, Kuwait and Iraq.

I suppose I did less than some, and more than others. Kinda like everybody else.



An old pic of me at the US Embassy, San Salvador, El Salvador, 1984. The first place I was ever directly shot at, while standing guard on the rooftop.

 

[SuckitTrebek]

Re: Down adjustment with 20moa base necessary?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MontanaMarine</div><div class="ubbcode-body">I spent about 8 years overseas, out of 25.

Earned over 48 months of hostile fire pay, imminent danger pay, combat pay, etc, in El Salvador, Croatia, Egypt, Kuwait and Iraq.

I suppose I did less than some, and more than others. Kinda like everybody else.





An old pic of me at the US Embassy, San Salvador, El Salvador, 1984. The first place I was ever directly shot at, while standing guard on the rooftop.

</div></div>

Might want the stars on that sea service deployment master guns!

Fuck I'm still feeling the effect of the bar from last night, semper fi

 

[k2peaker]

Re: Down adjustment with 20moa base necessary?

Thanks to both of you for your <span style="text-decoration: underline">years </span>of service.

Original question:
With a 100 yd zero on my PH (on a 20MOA AI base), I have .5 mils down avail. Don't think I've used more than +0.1 mils in tac matches. Real world? I'm no pretender.

 

[Lindy]

Re: Down adjustment with 20moa base necessary?

What you want is to have enough elevation to shoot to the farthest distance you wish to - but you don't want much more.

The reason is that when you get the scope close to the edge of the lenses, there may be more distortion of the image than there is near the center.

So, getting as much as you need is good, but don't go for as much as you can get unless you need it.

Heck, that sounds confusing even to me, and I wrote it...

But I think you get the idea. So, with that base, how much "up" do you have?

 

[ruth]

Re: Down adjustment with 20moa base necessary?

Approximately 37-38 moa up elevation.

 

[Lindy]

Re: Down adjustment with 20moa base necessary?

You said that you have 4 MOA "down" left, and 38 MOA "up". That means the total adjustment of your scope is only about 42 MOA.

If you're going to shoot tactical matches which include 1000 yards, you're right on the edge. Under some conditions, like on a cold day at sea level with a .308, you may have to hold over using the reticle.

Many people will not want to use a scope with that little elevation adjustment for tactical shooting, but you can get by with it, as long as you can get a 100 yard zero with it, and you don't plan on dialing windage.

 

[rezmedic54]

Re: Down adjustment with 20moa base necessary?

You really need the extra down on your scope. A very important shooter once told me why. It's when you go to adjust it that on your way down you go past your zero and come up to it and that should be done at every adjustment when coming down. This way you always work from the same side of the treads and I believe that on most 30mm scopes the spring is on the bottom side of the treads so by always working off the same side you always have the same tension against the nut. The shooter was David Tub.

 

[Lindy]

Re: Down adjustment with 20moa base necessary?

Assuming that's true, he doesn't need any more down, because even if his scope adjusts in 1 MOA clicks, which I doubt, he's got enough to go several clicks past his zero and then come up.

 

[ruth]

Re: Down adjustment with 20moa base necessary?

Lindy, with 42 moa total adjustment for scope, what is the max distance I would be able to shoot at regularly without running into trouble with dialing up so much elevation that my windage adjustments start to become effected/reduced?

Is there any way to know if a rifle is better off with a 20 moa or 30 moa base. I say this because the USMC went with a 30 moa base on M40A3, yet I beleive that the 3-12X50 scope they use will reach 1000 with a 20 moa base.

 

[Lindy]

Re: Down adjustment with 20moa base necessary?

The crucial criterion here is that if your scope has only 4.25 MOA of "down" available with a 20 MOA base, you're not going to be able to get a 100 yard zero with a 30 MOA base.

It's not possible to answer your question precisely, simply because many of the variables are unspecified. The scope the Marines are using has far more of an adjustment range than the scope you have.

 

[ruth]

Re: Down adjustment with 20moa base necessary?

Lindy, Of these 2 scopes, which do you think would make the better tactical scope and why?

Zeiss Victory Diavari 6-24x56 T Mildot Reticle .05 MRAD

Zeiss Conquest 4.5-14X50 T Mildot Reticle 1/4"

 

[Lindy]

Re: Down adjustment with 20moa base necessary?

I've no opinion, as I've never seen either of those scopes, and there are a lot of factors which go into the choice of a scope.

The primary items of interest to me in a scope are, with the highest preference first:

1. Reticle - is it one suitable for all lighting conditions, and can I use it easily for holdovers, holdunders, moving target leads, and wind holds? (That pretty much means a FFP reticle.)

2. Reliability. That means the scope must be rugged <span style="font-style: italic">and</span> the adjustment system must be repeatable and reliable.

3. Power Range. I'd like at least a 4-1 zoom ratio. For tactical shooting, I like a power range of 4-16. If I can get a 5-1 zoom ratio, I'd prefer 4-20.

4. Eye relief. Generous eye relief, and one which changes little with power changes.

5. Optical quality.

6. Price.