Range Report matched turrets

huntermanpaul

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Last summer I purchased a Vortex Viper pst 4x16x50. I spent the time this winter to develop a load that my Remington 700 pss .308 really likes. I am loading 175 gr burger vld's in Hornady match brass, varget powder, and cci primers. The load is printing .310" groups at 100 yds. Vortex offers a ballistic matched turret for the scope if you provide them with your load data. I jumped on their ballistic calculator and figured where I should be shooting at various ranges out to 1000 yds. At 1000 yards, their calculator and my actual range results are about 4 minutes off. How do i go about making and proving data to provide them with accurate info to build me a turret?
 

Leaddog

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Re: matched turrets

Check your scope tracking first.

Set up a 4 foot target at 100 yards. Starting at the bottom, fire one shot. Using the same point of aim, Dial up 4 minutes and fire another shot. Do this until you have dialed up 40 minutes. Now, work back down to your 100 yard zero.

Measure and record. Now you know if your scope is giving accurate elevation adjustments. Compare with ballistic calculator outputs.
 

huntermanpaul

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Re: matched turrets

Ok thanks! Presuming that the scope is tracing properly and I am not matching their ballistic calc, what next?
 

Leaddog

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Re: matched turrets

I suppose the obvious is your velocity. What is it? Did you chrono your rounds? Are you using the G7 BC of .255?

Post up your zero weather conditions and your range day conditions, if different and I'll run the numbers through my ballistic programs.

I'll need:
Field elevation
Barometric Pressure
Temperature
Humidity
Dew Point, if you have it.
 

roggom

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Re: matched turrets

Did you watch the Vortex video's? There is good instruction on how to "validate" your actual long range drop vs the calculator. That is why like the LRBC/G7 software, it will either adjust your velocity or BC to give actual drop for your load/rifle. Very intuitive software, you do not have to be so dependent on a chrony or manufactures bloated BC numbers.

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Leaddog

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Re: matched turrets

If you didn't record the conditions, I'll need the range location or nearest town, the date, time of day, and I'll look up the historical weather records and get it.
 

huntermanpaul

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Re: matched turrets

I shot 10 rounds through the chrony and had an average of 2733 fps i did base it off of the g7. Altitude at the range is 5075, temp was 48, and I guessed the humidity at 50% that should be close, pressure 24.82. I am zeroed at 200.
 

TOP PREDATOR

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Re: matched turrets

piece of tape and a sharpie

paint current face white, then a covering of flat black. scrape off the black to mark your dope with an exacto knife without scraping off the white.

you can go multilevel with it then (0 X # of revolutions) on a second row of numbers.

call and see if they can match that with the laser etched engraving, then send them the painted turret or tape.

of course to be truely accurate, you'll need three: summer, winter, and spring / fall for at least the a common temperature / humidity aspect.
 

Leaddog

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Re: matched turrets

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: huntermanpaul</div><div class="ubbcode-body">I shot 10 rounds through the chrony and had an average of 2733 fps i did base it off of the g7. Altitude at the range is 5075, temp was 48, and I guessed the humidity at 50% that should be close, pressure 24.82. I am zeroed at 200. </div></div>

I see the problem. You used Absolute Air Pressure instead of corrected. Since air pressure changes about 1 inch per thousand feet, you should have been using approx. 29.90 as your pressure. You'll see about 3+ minutes of elevation difference in your ballistic data come ups at 1000 yards.
 

George63

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Re: matched turrets

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Leaddog</div><div class="ubbcode-body">Check your scope tracking first.

Set up a 4 foot target at 100 yards. Starting at the bottom, fire one shot. Using the same point of aim, Dial up 4 minutes and fire another shot. Do this until you have dialed up 40 minutes. Now, work back down to your 100 yard zero.

Measure and record. Now you know if your scope is giving accurate elevation adjustments. Compare with ballistic calculator outputs. </div></div>

you will not see it at 100 yds until you go past 20 minutes but remember a minute of angle is actually 1.047 inches per 100 yds
 

huntermanpaul

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Re: matched turrets

Thanks for the information! I am hoping to make it out shooting on Saturday. If I do, I will be back with my info.
 

427Cobra

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    Re: matched turrets

    These are a waste of time, if BDC knobs actually worked all scopes would have them, but they don't because there a companies wet dream of sucking money out of new shooter wallet, learn how to use a scope, learn about ballistics, and to successfully deploy that knowledge.
     

    roggom

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    Re: matched turrets

    I have mad my own with white electrical tape and a sharpie. Then cover that with a film of clear packing tape. The turret is then as good as your drop chart for that load and shooting area.