turrets

Brownie

Brownie

New member
So i posted this question on another forum but need all the help i can get. Im trying to understand the MOA concept for long range shooting. So 1 MOA at 100 yards is 1 inch and 4 1/4 inch clicks at 100 would equal 1 inch or 1 MOA. so at 500 yards 1 MOA is 5 inches and a 1/4 inch click on the turret is equivalent to 1.25 inch at 500 yards. so with my ballistics program i figured out my bullet drops 51.7 inches at 500 yards or 9.9 MOA. which would mean if my math is correct i would have to adjust about 40 clicks up on the elevation knob to compensate for the drop?? am i correct in my theory and my math?? if not where am i going wrong or what do i need to change. any help would be greatly appreciated.
 
You have the concept understood and your math looks right. 1 MOA isn't exactly one inch at 100 yards, but it's close enough for most applications.
 
I agree, it all looks pretty good. I wouldn't count 40 clicks though. That's one of the reasons u calculate trajectory compensation in MOA. The turret itself should be calibrated in MOA--whole numbers and hashmarks.
 
Originally Posted By: sscoyoteI agree, it all looks pretty good. I wouldn't count 40 clicks though. That's one of the reasons u calculate trajectory compensation in MOA. The turret itself should be calibrated in MOA--whole numbers and hashmarks.

thinking in MOA instead of clicks makes it easier. don't need all the math.
 
if you don't use the clicks then you have to take your eyes off of the target....at 500 yds it is extremely hard to pick them up again if you look away to "see" your turrets. It is real easy to lay there and crank the turrets in sets of ten and you never have to take your eyes off the prize.
 
Wait a minute. Did I miss something?

What did you zero the scope for before you made the adjustment to 500 yards and how high above bore was scope mounted.

The ballistic programs that I am familiar with require those two data points along with muzzle velocity, ballistic coefficient, grain etc.


Meaning if I my scope is zeroed at 100 yards. it is going to take more elevation change to adjust for a 500 yards target than if I were zeroed at 200 yards, correct?
 
Originally Posted By: CT Shamrock
Meaning if I my scope is zeroed at 100 yards. it is going to take more elevation change to adjust for a 500 yards target than if I were zeroed at 200 yards, correct?

even though your scope may be zero'd at 200 yards, you still have the elevation "used" to obtain that 200yd zero, what i'm saying is, although it may take you less minutes to get to 500 with a 200yd zero, you WILL run out of elevation just as fast as you did using a 100yd zero... on another note, counting clicks according to your pda or ballistic program is meaningless unless you know the EXACT value per click, and i'm not talking what is stated on the turret or owners manual, even though most moa scopes are .250moa per click, most cheaper end scopes don't hold that value, heck i have 4 NXS's and two of em don't hold a .250moa value per click... IF you want to make first round hits, start from the basics, and begin by calibrating your optic.
 
Skinney

We agree. That is one difference between South Dakota and Connecticut. I can count the 500 yards rifle ranges here in CT on one hand with several digits left over.

I am using a Sightron Big Sky S3 6 x 24 x 50 mil dot with target turrets and 0.10 mil clicks on a 6.5 Grendel AR. It seems to track very precisely (at least at the 200 yard range I was testing at). Yes, you can run out of elevation adjustment in some scopes quickly at long range and some do not track very precisely.

Now, if I lived near to you in South Dakota, I would verify that 500 yard shot and my scope tracking adjustments / accuracy with actual live fire. That is absolutely the preferred route, no question about it.

It is not a shot I will get very often here.
 
Originally Posted By: CT Shamrock

It is not a shot I will get very often here.


well if your ever in SD look me up, i have a 1200yd range in my backyard!!!
 
Well [beeep], there is another one for the "Bucket List"!!

So if fishing and upland bird hunting is a "cast and blast" trip, what would an upland birds and predator hunting trip to SD be called?

I see an unfilled niche here for you!

Regards.
 
Originally Posted By: skinneyeven though your scope may be zero'd at 200 yards, you still have the elevation "used" to obtain that 200yd zero, what i'm saying is, although it may take you less minutes to get to 500 with a 200yd zero, you WILL run out of elevation just as fast as you did using a 100yd zero...

exactly.
CT, this is why you see alot of 'long range' rifles that have a canted base for the scope to mount on.
A canted base automatically puts your scope at a deficit with regard to DOWN adjustment. That deficit in DOWN adjustment allows you to have MORE UP ADJUSTMENT available in your turret.

For example, say, in a pefect world with easy math, your scope has 100MOA total in elevation travel.
And let's assume that with your scope zeroed on your rifle with a 0 degree (flat base), you have exactly 50 MOA UP and 50MOA DOWN elevation. IE, the scope is perfectly in the middle of it's available erector travel...

OK, now take that SAME combo, but mount that scope on a 20MOA canted base atop the rifle.

NOW, after zeroing the rifle & scope again, thanks to that extra angle from the canted base, you'll only have 30 MOA DOWN travel left on your scope. The 20 MOA base 'used up' that amount of travel to get you back on zero.

BUT, (to the benefit to us long range shooters) there is now 70 MOA of UP travel now useable in the scope from that new zero point
smile.gif


Another benefit to using a canted base is that as you dial that UP elevation on longer shots, you are moving the scope through the middle of it's erector travel. Which is much more forgiving on the internals, kinda like not having to go too hard over on your steering wheel to make a U-turn...
wink.gif


make sense?
 
Originally Posted By: knockemdownOriginally Posted By: skinneyeven though your scope may be zero'd at 200 yards, you still have the elevation "used" to obtain that 200yd zero, what i'm saying is, although it may take you less minutes to get to 500 with a 200yd zero, you WILL run out of elevation just as fast as you did using a 100yd zero...

exactly.
CT, this is why you see alot of 'long range' rifles that have a canted base for the scope to mount on.
A canted base automatically puts your scope at a deficit with regard to DOWN adjustment. That deficit in DOWN adjustment allows you to have MORE UP ADJUSTMENT available in your turret.

For example, say, in a pefect world with easy math, your scope has 100MOA total in elevation travel.
And let's assume that with your scope zeroed on your rifle with a 0 degree (flat base), you have exactly 50 MOA UP and 50MOA DOWN elevation. IE, the scope is perfectly in the middle of it's available erector travel...

OK, now take that SAME combo, but mount that scope on a 20MOA canted base atop the rifle.

NOW, after zeroing the rifle & scope again, thanks to that extra angle from the canted base, you'll only have 30 MOA DOWN travel left on your scope. The 20 MOA base 'used up' that amount of travel to get you back on zero.

BUT, (to the benefit to us long range shooters) there is now 70 MOA of UP travel now useable in the scope from that new zero point
smile.gif


Another benefit to using a canted base is that as you dial that UP elevation on longer shots, you are moving the scope through the middle of it's erector travel. Which is much more forgiving on the internals, kinda like not having to go too hard over on your steering wheel to make a U-turn...
wink.gif


make sense?

+1

Let me add one thing. I use a 1 inch grid chart to check the scope. To see if it moves what I dope. I put my laser bore finder in first and then start turning. It will show if your scope is sticking.
 
I think I get it. Is the only use for a 20MOA canted base to provide elevation range for very long shots? It would seem so.

Funny thing here (New England) is that sometimes the cover is so wooded and thick you are better off with a shotgun and open sights than a rifle and scope. Every spring I meet some local turkey hunter whose decoys got mauled by a coyote 20-30 yards in front of them.
 
Originally Posted By: CT Shamrock Is the only use for a 20MOA canted base to provide elevation range for very long shots?

Primarily yes... although alot of guys get them without ever using the added up the mount or base provides.
 
Originally Posted By: skinneyOriginally Posted By: CT Shamrock Is the only use for a 20MOA canted base to provide elevation range for very long shots?


Primarily yes... although alot of guys get them without ever using the added up the mount or base provides.

What skinney said plus...
It you're gonna put a rail on and dial,might aswell have some MOA in the base. I'd rather have it than not.
cool.gif
 
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