Home Forums Hunting & Shooting Long Range Hunting kind of new to turret twisting.....maybe a stupid question but...

so if you are shooting at 1000yds and it calls for 53.8 inches of elevation, that is equivalent to 5.38 inches of elevation at 100yds correct? I have in the past just shot with holdover reticles out to about 600 or so, but got a couple of guns that I want to try to take out to 1k on my farm.........not new to shooting but the long range things is a somewhat new area for me, as is turret twisting.

I suggest you use a program like JBM. While the first time getting all the inputs done may be a bit daunting your reward will be
turret twist outputs in the form of MOA or Mil-Rad

http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi



one input that might be difficult is true barometric pressure that accompanies altitude. To help you along:

2000 27.80
3000 26.82
3500 26.33
4000 25.84
4500 25.37
5000 24.90
5500 24.43
6500 23.57
7500 22.71
8000 22.23
9000 21.27
9500 20.79
10,000 20.31

The is second column to right of distance will show you how much to twist the turret. Some of the amounts for MOA are not possible as the typical MOA turret in set in .25 increments. Simply round up or down to nearest increment.

You will need to know the velocity and TRUE BC of the bullet. If there are any discrepancies with the POI at distance IMO you are better off tweaking velocity than BC.

No....with an assumed 100 yard zero, it's 53.8" high at 100 yards to be on at 1K.

I plan to shoot the ranges from 100 out to 1000 and develop the actual drops from shooting. I am just asking that the multiplier of the turret is equivalent to the range compared to 100 yds....I.E. @200 yds, one inch of adjustment for 100 yds will be 2 at 200, 3300, 4400 so on an so forth out to 1k.....so 1 inch of adjustment at 100 yds is 10 inches of adjustment at 1000 yds....is that correct?

so there is not multiplier to the elevation turret? if the turret says 1/4 inch @ 100 yds, isn't that equivalent of 1 inch of travel at 400? or 2.5 inches at 1000?

No multiplier.....

Stop thinking of inches and clicks. Think only of MOA(or mil).

Run the ballistics on JBM in MOA. In simple terms w/ a Leupold scope, when it says 23.75 MOA to be on at 1K, dial in 23 full numbers and 3 more clicks, and shoot.

Yes, you're right. But I'm with aalf- the sooner your stop thinking in terms of inches and clicks, the better. If your scope uses MOA increments, then think about MOA only, and that will be consistent regardless of what distance you're shooting. So your data might be something like 200 yards- dial up 1.5 MOA, 400 yards- 6 MOA, 1000 yards- 28 MOA, etc. No need to complicate things with conversions, multipliers, etc.

But the scopes I have are inch adjustments....and inches and MOA are not a direct correlation though correct?

Correct. Doesn't sound like a scope that will lead to success or confidence for LR shooting. What scope are you using? Using the wrong scope will only lead to frustration. It's well worth having an appropriate scope when getting into this game.

They are the Nikon Prostaff 7s. one is a 2.5-10 and the other is a 4-16. The andjustments seem to be good and accurate as far as what testing I have done on them but again this is all new to me as far as the turret twisting.

I had a couple of Vortex Vipers...one the HST and the other the HS-LR, but honestly they kind of sucked to me optically.......the Nikons are clearer to me

For a few hundred bucks, I'd suggest you pick up a SWFA SS 10x to learn on. I started getting into LR shooting about 15 years ago when Leups, B&L 4200, Burris FFII w/BP, Monarch w/BDC, Conquest w/RZ600, etc, were all I had to work with. The only reliable scopes I knew about at the time were $1500+, which was outside of my university student budget. The Nikons I've played with have either immediately or eventually let me down in the mechanical department. It's extremely frustrating when you're trying to learn the physics of ballistics, wind, scope mechanics, etc, when you don't know if you're missing because of the scope, or because you've made a mistake. We are extremely fortunate these days- scope manufacturers are catching onto the fact that we want scopes that work, not just scopes with clear glass, so we've got several mechanically-reliable options in most every price range.

You also need to stop worrying about how clear your Nikon is and use a scope with a real turret. Jordan's spot on.

aalf shoots a little longer range type stuff too....grin

Just in time....I had a drone headed your way........bigger grin....

I don't have a problem spending money on good glass(that doesn't necessarily mean most expensive to me) and can afford it, so its no big worry to me honestly. How are the SWFA variables comparing to the fixed powers? Ill probably get thru our deer season with what I have and rework the scopes over the winter.

You have been given good advice. I'll just add this: when I got a Jeep, my buddy described Jeep ownership as "Finacial sodomy, plus joining a cult!".... LR shooting is like that.

Couple suggestions.... run a Tall Target Test at 100 yards on your existing scopes. That will tell you lots about your scopes mechanically, and plus that, help wrap your brain around the math of it. Look for things like the actual POI drifting left or right relative to the vertical stadia.... windage changes when you've only dialed elevation.... failures to repeat (big groups) as you dial between shots.... Etc. Maybe what you have is awesome and will do the job! One way to find out.

This is a pic of such a test I ran years ago. I was dialing 4 MOA between every shot. See the error in windage at 8 MOA? That scope still sufficed to kill steel plates to 900 or so and a deer at 600, but that's not ideal.



(Please note that this is really more of a "medium target test".... and that I was not super-rigorous about it. You can get as geeky as you want with these tests. However, even simplified ones as above can tell you a LOT in the early going. )

A similar test on my Swaro 3-10 revealed that the mechanical tracking was not true to the vertical reticle stadia. As I dialed in more elevation, holding the reticle plumb to the plumb-line on the target, the POI drifted off to the right, to where it was about 1.5 MOA off in windage at 16 MOA of elevation, if memory serves. Other than THAT, it tracks and repeats pretty well! But that's a big deal. This is a very messy target as I was running a similar test on another scope. It was never meant for public consumption, but I'm including it so you can maybe see what I'm trying to say here. 1000 words and all that.

The variables are great, too, and will easily get you to 1000 if you're using good bullets at reasonable speed. If budget isn't a limitation, then also consider the Bushnell LRHS and DMR/ERS, Nightforce NXS, and Vortex Razor Gen II. There are also other good options, but the price goes way up. Size and weight vary among the options, so you'll have to take all that into consideration for your specific rifles and uses, but all of those options have proven to be mechanically robust.

Yes, inches/100yd and MOA are directly linearly correlated. At 100yd, 1 MOA equals approximately 1.047". If your turret adjustments are 1/4" @ 100yd per click then your scope adjustments are (1/1.047)/4 MOA per click which is ≈0.239 MOA per click.

The advice to start thinking in terms of MOA [or mRADs] is good advice. If you know your bullet's muzzle velocity [MV] and ballistic coefficient [BC], you can use any good ballistics calculator to compute a table of MOA drop vs range for a given scope zero range [usually 100yd]. The BC is fairly easy to look up. The MV can be measured with a chronograph or some other device or alternatively can be calculated by most ballistics calculators using the actual measured drops at several distances for a given bullet and BC.

As Azshooter mentioned there are numerous other inputs to ballistics calculators that you will need to know or estimate such as absolute barometric pressure [that is actual station pressure - not corrected sea level pressure usually reported by weather services], temperature, humidity [although this is not very critical - 50% is a good compromise], crosswind velocity and direction component, scope sight height above the bore, target inclination angle, etc. and if you are serious about shooting to 1000yd things like barrel twist rate, firing azimuth, latitude, etc. start to become important. Also don't overlook range estimation errors.

The advice from Jeff O to perform a tall target test to measure scope adjustment tracking is definitely good advice if you intend to dial turrets for distance correction. These scope tracking factors [SF] can also be inputs to some ballistics calculators or you can just manually correct the ballistics calculator tables drops and windages for the SF. If you are shooting out to 1000yds, you should also consider some sort of anti-cant level to insure that your rifle hold is correctly aligned to the vertical to reduce cant error. Another factor to keep in mind is the available scope elevation adjustment for shooting to longer ranges - some scopes will not have enough adjustment available and you will need to add additional hold-over or install scope bases/rings/mounts which have a built-in elevation for long range shooting.

Think fast- 28.65 MOA correction, what do you set the scope to?

I think he was asking if IPH and MOA were equivalent.