Long Range Firing Solutions

[17LiveFree76]

+1 for Applied Ballistics. They have custom drag curves for hundreds of projectiles they actually measured using some high-end doppler radar (not LabRadar, $100k type radar), and if I remember, measured past trans-sonic. Here's an article from Precision Rifle Blog about BC. Check it out, they talk about how not only projectile consistency but things like what kind of muzzle brake you are using can affect your BC.

Personalized Drag Models: The Final Frontier in Ballistics?

I am super-excited about this article! I've actually been working on it for a couple of months, and...

precisionrifleblog.com

My rangefinder has a built in weather station (wind meter run from cell phone linked to rangefinder) and uses BA drag curves.

I've just been entering the bc posted on the box. Would it be better to change that instead of lying about velocity?

 

[Koda]

I have to lie about my velocity to get the range finder to calculate my ark correctly.

it sounds like the only variable you havent accurately double checked is your BC. I would adjust that until it matches your drops.

 

[Member 34319]

This rifle is zeroed at 100 yards. I just shot 6 rounds and only have 1 hole in the paper. It's extremely accurate. 24" proof barrel on custom grind action rem 700. It shoots great out to 1000. The thing that baffles me is with this rifle and several others, I have to lie about my velocity to get the range finder to calculate my ark correctly. This causes me trust issues out past 500 yards

Just checking. Sounds like the Sig range finder should stick to finding ranges then? Might also be something worth reaching out to Sig about if it was purchased for the ballistics calculator? Especially considering that it isn't just the one set of calculation/rifle data error, it seems to be any rifle/ammo information. I' call them and see if they can help you?

 

[17LiveFree76]

I entered the data from Post #12 into Hornady's 4DOF calculator. I'm confused though. You say the original solution had your rifle shooting high. But adding 200 fps fixed it, meaning adding muzzle velocity made your rifle shoot lower?

Anyways, no mention of zero-range or scope height in Post #12 so I substituted 100 yards and 1.88" respectively. As you can see in the results below, adding 3150 fps lowers the come-ups at 600 yards by over 2 MOA.

So, what exactly is it you're trying to calculate?

MV=2875

RANGE (YDS) TOTAL COME UP (MOA) TOTAL WINDDRIFT (MOA) GYRO
0 0 0 3.23
100 -0.38 0.38 3.46
200 +0.93 0.8 3.72
300 +3.01 1.23 3.99
400 +5.4 1.69 4.25
500 +8.05 2.17 4.54
600 +10.95 2.7 4.86



MV=3150

RANGE (YDS) TOTAL COME UP (MOA) TOTAL WINDDRIFT (MOA) GYRO
0 0 0 3.26
100 -0.35 0.34 3.48
200 +0.59 0.69 3.73
300 +2.24 1.06 4
400 +4.18 1.45 4.3
500 +6.33 1.85 4.61
600 +8.68 2.3 4.9

By

I run Applied Ballistics which is a $30/app and never been bothered by the cost when you consider that is less than one wasted box of centerfire rifle ammunition these days. Have also run Strelok but won't be putting any more effort into that app until the stupid sanctions are lifted. Based on your comment that all your rifles are shooting high in comparison to the initial dope in your app it leads me to believe that either a setting isn't getting setup correctly or an input is consistently off. Have you compared your chrono's data to another chronograph to make sure it is pulling accurate velocities within an acceptable margin of variance?

I know this may sound like a really silly question but is your app setup for the proper unit of measure your using? We use a range that is setup in meters frequently and were told it was yards and did not verify each berm/target prior to starting to shoot. All our drop tables were in yards and we started to have a heck of a time 400 yards and out. Then one of us lasered the targets and found out everything was in 100m increments instead of 100yd increments. Adjusted our apps to meters and everything was back to spot on.

With good inputs for BC (G1/G7), twist rate, height over bore and velocity along with good environmental's I have only had to do very minor truing of ballistic data. Our typical process has us verifying zero at 100-yards while collecting chrono data, then input data into Applied Ballistics, fire a group at 800 yards to see if drop data is correct or we need to tweak ballistics to true to actuals and then take it out to 1000-yards plus. If we run into any issues at the longer distances we bring things back and trouble shoot. Does your app ask for what distance your zero is set at?

The sig app doesn't ask for near enough info but the shooter app does. I have not tested the shooter app yet but by the MOA it is giving me I think I will hit high with it as well

 

[ORhutner]

By

The sig app doesn't ask for near enough info but the shooter app does. I have not tested the shooter app yet but by the MOA it is giving me I think I will hit high with it as well

If a different ballistics app is giving you similar drops then this leads me to think it has something to do with your inputs. This is a hard problem to trouble shoot remotely. In general, a good muzzle velocity average and correct bullet BC with correct barrel twist rate should get you very close in a modern ballistic calculator app 1,000 yards and in.

What optics are you using? I doubt it is the tracking in the optics but that is one more possible variable. Is your scope in MIL's or MOA?

What is your ballistic app saying for your elevation adjustment at 500 yards vs. actual needed so that point of aim is the same as point of impact?

 

[DLS]

I've just been entering the bc posted on the box. Would it be better to change that instead of lying about velocity?

Yes!

 

[17LiveFree76]

If a different ballistics app is giving you similar drops then this leads me to think it has something to do with your inputs. This is a hard problem to trouble shoot remotely. In general, a good muzzle velocity average and correct bullet BC with correct barrel twist rate should get you very close in a modern ballistic calculator app 1,000 yards and in.

What optics are you using? I doubt it is the tracking in the optics but that is one more possible variable. Is your scope in MIL's or MOA?

What is your ballistic app saying for your elevation adjustment at 500 yards vs. actual needed so that point of aim is the same as point of impact?

 

[17LiveFree76]

Yes!

Would I increase the number?

 

[17LiveFree76]

The info I entered above is the new app I have not tried yet. My sig Calc doesn't ask for near the info.

 

[drstrangelove]

Never fudge the velocity. Fudge the BC until you impacts are correct. Make sure your bore center to scope center is entered correctly.

 

[ferret427]

I've just been entering the bc posted on the box. Would it be better to change that instead of lying about velocity?

I think that in the Applied Ballistics website library (and also maybe referenced in an older article on Precision Rifle Blog) they published a white paper on when calculating a projectiles flight path, how and when to true either BC or MV so that a calculator can be adjusted to reflect observed behavior, to tune your calculator to better predict a firing solution. Sometimes a MV adjustment is needed, others is BC, depending on where in a projectile is in its flight.

Might have to dig to find it...I think I have seen posts on Sniper's Hide and maybe Accurete shooters about this as well.

 

[17LiveFree76]

Never fudge the velocity. Fudge the BC until you impacts are correct. Make sure your bore center to scope center is entered correctly.

I think that in the Applied Ballistics website library (and also maybe referenced in an older article on Precision Rifle Blog) they published a white paper on when calculating a projectiles flight path, how and when to true either BC or MV so that a calculator can be adjusted to reflect observed behavior, to tune your calculator to better predict a firing solution. Sometimes a MV adjustment is needed, others is BC, depending on where in a projectile is in its flight.

Might have to dig to find it...I think I have seen posts on Sniper's Hide and maybe Accurete shooters about this as well.

I'd definitely be interested in hearing about that

 

[ferret427]

I'd definitely be interested in hearing about that

I seem to remember some of the MV truing came from distance to chrony, and some other factors. Been a few years...sorry I don't remember more, but I remember there are instances where velocity was adjusted.

I'm not good enough of a shot, and never get to shoot far enough where it really matters <sigh> someday I will live in wide open spaces instead of Western WA and can experiment...

The info is out there, you just gotta go digging.

 

[ORhutner]

I seem to remember some of the MV truing came from distance to chrony, and some other factors. Been a few years...sorry I don't remember more, but I remember there are instances where velocity was adjusted.

I'm not good enough of a shot, and never get to shoot far enough where it really matters <sigh> someday I will live in wide open spaces instead of Western WA and can experiment...

The info is out there, you just gotta go digging.

If you can shoot 1" groups at 100 yards then you have the capability already to get consistent impacts at 1,000 yards. Especially if you have a good spotter capable of making wind calls.

 

[ferret427]

1" @100 is no issue at all. I usually get 1-.75" 5 round groups with my AR10, more .75 than 1" (my housemate can get .75 moa or a little less at 300 with it pretty often, one .3moa that I remember).

I'm heading to Idaho this fall to visit the folks. There's a range on the way called Parma Rod and Gun Club. I'm going to check them out. They have range over 1000 and events out to a mile. Would be great to try some long range. Though with .308, 1000 will be far enough . I just want to try to hit something really far and can't do it around here.

 

[17LiveFree76]

1" @100 is no issue at all. I usually get 1-.75" 5 round groups with my AR10, more .75 than 1" (my housemate can get .75 moa or a little less at 300 with it pretty often, one .3moa that I remember).

I'm heading to Idaho this fall to visit the folks. There's a range on the way called Parma Rod and Gun Club. I'm going to check them out. They have range over 1000 and events out to a mile. Would be great to try some long range. Though with .308, 1000 will be far enough . I just want to try to hit something really far and can't do it around here.

I used the shooter app Friday. It was spot on the money with its calculations. I got out to 1100 yards My solutions hit their mark at all ranges and angles in between.

 

[Member 34319]

I used the shooter app Friday. It was spot on the money with its calculations. I got out to 1100 yards My solutions hit their mark at all ranges and angles in between.

So, returning the range finder? I have considered one of those and I'm sort of glad this thread came along.

 

[17LiveFree76]

So, returning the range finder? I have considered one of those and I'm sort of glad this thread came along.

I'll return the kilo 5 but I ran a 1800 with my last rifle that never let me down. I usually wait a few years before electronic gear comes out before I buy one so they have a chance to work out the bugs. I didn't do that with the k5. I will get another one and try it. Especially now that I have this app to compare solutions. One bad thing about the sig is the firing solution only goes to 800 yards. Even though it ranges past that

 

[erslll]

I use my Kilo 5 for ranging. I let my Kestrel with AB do the math. I am pretty impressed with the ranging ability of the Kilo 5.

 

[17LiveFree76]

Does anyone know what velocity is needed for a 212g Hornady ELD-X to expand correctly and be lethal on an elk?