Dope estimation?

[Chernobyl]

• #1

Does anyone know of an app or can help me estimate projected drops at longer distances. I do not have a chronograph at this time and tired of wasting ammo trying to figure out dope for varying yardages. I’m currently shooting Berger vld target 140 gr pills with 39.3 grains of H4350. At 500 yards I am dialed in at 10 MOA up, at 600 yards I’m dialed in at 14 MOA up, at 700 yards I’m dialed in at 18.5 MOA up, and at 800 yards I’m dialed in at 23.5 MOA up. I’m trying to figure out MOA needed for 900 yards and up in 100 yard increments. Any assistance is appreciated.

Rifle is a 6.5 RPR

 

[rardoin]

Running a Berger 140 hybrid at 2720 +/- fps in an RPR was about 12.5-13 MOA @ 600yds near 30 feet above sealevel. I calculate your estimated V at 2625fps. This gives a come-up of about 27 MOA @ 900 and 33 MOA @ 1000yds at about 50' ASL/70deg F. This would probably 'get you on paper'. I suggest downloading the Strelok Pro app (or Applied Ballistics app)... borrow a chronograph and get a velocity average for you load.

 

[rwj]

• #1

Does anyone know of an app or can help me estimate projected drops at longer distances. I do not have a chronograph at this time and tired of wasting ammo trying to figure out dope for varying yardages. I’m currently shooting Berger vld target 140 gr pills with 39.3 grains of H4350. At 500 yards I am dialed in at 10 MOA up, at 600 yards I’m dialed in at 14 MOA up, at 700 yards I’m dialed in at 18.5 MOA up, and at 800 yards I’m dialed in at 23.5 MOA up. I’m trying to figure out MOA needed for 900 yards and up in 100 yard increments. Any assistance is appreciated.

Rifle is a 6.5 RPR

Use Berger’s calculator... https://bergerbullets.com/ballistics-calculator/

 

[CharlieNC]

Most ballistic apps for your phone include a truing function wherby you enter actual results such as you have, and the app will calculate the velocity to use going forward. I like Strelok Pro, I think $10

 

[JLT]

Here you go . . .

Range, yards Come-up (MOA)
500 10.0
550 11.9
600 14.0
650 16.2
700 18.5
750 20.9
800 23.5
850 26.2
900 29.0
950 31.9
1000 35.0
1050 38.2
1100 41.5
1150 44.9
1200 48.5
1250 52.2
1300 56.0
1350 59.9
1400 64.0
1450 68.2
1500 72.5
1550 76.9
1600 81.5
1650 86.2
1700 91.0

The above is the output of a simple quadratic model, using your measured DOPE and fitting an X, X^2 form to the data you reported. The fit is quite good, with an r-squared and an adjusted r-squared indistinguishable from 1.00. The predicted values for your reported data are right on the money. Should be very close for YOUR GIVEN LOAD. Let me know if you'd like the coefficients or an Excel file containing the model.

BTW, a chronograph will save you money over the long run. If you so much as change the primers you're using, the above data may or may not fit acceptably.

Good luck!

 

[Rsadams]

I have had good luck with the Lapua program , it's free...

 

[CharlieNC]

Its helpful to have an app with you, since the phone measures barometric pressure and you input actual temperature plus wind as it changes frequently. Best $10 you will spend for shooting long range.

 

[Delfuego]

Borrow a chronograph

 

[pirate ammo]

Borrow a chronograph

or get a donation,, yup

 

[K22]

There's nothing that beats chronographing the load to get your average velocity but if that is not possible you can get an approximation by accessing shooterscalculator.com and estimating your velocity.

If by shooting at the range know the bullet rise and drop between two points, i.e. 100 and 200 yards for your current load you can manipulate the velocity and zero range input in the program to matches this and get an approximation of bullet drop over the extended ranges you desire by selecting the max range and increments, e.g. 400 yards in 25 yard steps.

For example I have my 223 Rem 26" barrel sighted +1.25* inches at 100 yards. Shooting at the range I've averaged about a -0.4* drop at 200 yards. By manipulating the software to match this rise and drop of the bullet I estimate the approximate velocity is 3,200 f/s and zero range is 191 yards for a 55 Nosler (BC = .267*) with a scope height of 1.5"* and 80* degree temp. These inputs match the known bullet rise and drop. This a backwards way of doing it but it's reasonable close, at least better than trying to guess at it.

* known values

 

[dsculley]

Easy way: go to JBM Ballistics (https://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi), put in the required information for your set up including sight height. Estimate your MV and check the output. Adjust the MV until the output matches your real world info (use your longest known range). The projections will be very close. You can then verify and adjust to actual. The more precise your inputs the closer to actual the output.

For instance, I input some estimated information as well as the bullet info to match your 800 yd adjustment and got 28.5 for 900 & 34 for 1000.

No matter how you calculate your dope you will still need to prove it and adjust as needed. Once I get my dope, I prepare a card in 25 yd or 25 m increments.

 

[Delfuego]

Use your loaner Chrono and get an accurate speed. Use JBM online for free, or Shooter app for $10 on your phone. Those 2 items will have you doing better than 90% of everybody

Good luck!

 

[Chernobyl]

Thanks for all the input guys!

 

[wkdickinson]

• #1

Does anyone know of an app or can help me estimate projected drops at longer distances. I do not have a chronograph at this time and tired of wasting ammo trying to figure out dope for varying yardages. I’m currently shooting Berger vld target 140 gr pills with 39.3 grains of H4350. At 500 yards I am dialed in at 10 MOA up, at 600 yards I’m dialed in at 14 MOA up, at 700 yards I’m dialed in at 18.5 MOA up, and at 800 yards I’m dialed in at 23.5 MOA up. I’m trying to figure out MOA needed for 900 yards and up in 100 yard increments. Any assistance is appreciated.

Rifle is a 6.5 RPR

Just MPOI - buy a copy of "Shooter" for your tablet or cellphone, then back into the MV from your drops at 500 & 600 yds. It's slow and cumbersome but with good long range date you should be able dial it in pretty close. But then again if you have good 500 & 600 yd data, what are you looking for, windage?

 

[pirate ammo]

got a crono I'm sending out that may help him.

 

[Dusty Stevens]

I like strelok pro and labradars. Cant imagine trying to do it without em.

 

[Webster]

• #1

Does anyone know of an app or can help me estimate projected drops at longer distances. I do not have a chronograph at this time and tired of wasting ammo trying to figure out dope for varying yardages. I’m currently shooting Berger vld target 140 gr pills with 39.3 grains of H4350. At 500 yards I am dialed in at 10 MOA up, at 600 yards I’m dialed in at 14 MOA up, at 700 yards I’m dialed in at 18.5 MOA up, and at 800 yards I’m dialed in at 23.5 MOA up. I’m trying to figure out MOA needed for 900 yards and up in 100 yard increments. Any assistance is appreciated.

Rifle is a 6.5 RPR

You should be able to use the Berger Ballistics program backwards. You know the drop at 800 yards. Keep programing in different fps for your load until the Berger output drop matches your known drop at 800 yards.

 

[Bc'z]

got a crono I'm sending out that may help him.

I totally forgot about that