Ballistic App/Dope Help

[orientalexpress]

I'm a noob at this Ballistic app / long range stuff, I thought I had a grasp on what was going on but something that happened yesterday makes me want to pull my hair out. I'm hoping one of you guys to explain or confirm that it's common.

Basically, we went out a week ago and doped our rifles at 600 and 750. Logged the elevation, weather conditions, etc. We had chrono'd the week before in different conditions, but we used that MV to plug into the ballistic app. We figured it would be close enough for us to hit something at those distances but we could tweak and confirm. If I recall it was a difference of about .5 mils.

Yesterday under similar (almost identical) weather conditions our dope at the same distances were a difference of .9 mil at 600 and 3.2 at 750. I thought maybe the scope was off, or my reloads were bad, or something but my friend experienced the same thing. We have an identical rifles shooting identical loads (each loaded individually) except his barrel is a little longer than mine. His dope was way off from the week before as well.

I calibrated in the ballistic app it reverse calculates it to give me a muzzle velocity of 2150fps vs the 2628fps we got when we chrono’d 2 weeks before. Once it was calibrated it was pretty close at 1000. I realize that atmospherics/weather can play a fact but that seems severe given the similar conditions and identical location. Something doesn't seem right, what am i missing? Any insight would be greatly appreciated.

 

[Lowlight]

sounds like a lot of shooter error in there, if you are seeing that big a variation and that big a deviation from the actual MV.

I would bet aside from Shooter Errors, there are other inputs added incorrectly.

Lining up your computer at 600 yards to match your recorded hits should not produce this big a variation without a lot of "bad data' or poor shooting involved.

 

[ShtrRdy]

Were you shooting from a different position or supporting the rifle differently?

 

[orientalexpress]

Were you shooting from a different position or supporting the rifle differently?

No from a bench/bipod.

 

[Lowlight]

screen shot your set up screens and ballistic screens, we will find the issue

 

[orientalexpress]

sounds like a lot of shooter error in there, if you are seeing that big a variation and that big a deviation from the actual MV.

I would bet aside from Shooter Errors, there are other inputs added incorrectly.

Lining up your computer at 600 yards to match your recorded hits should not produce this big a variation without a lot of "bad data' or poor shooting involved.

I would tend to agree it's the shooter, and I also agree that there could be some bad data in there. I'm trying to figure out where I went wrong.

 

[orientalexpress]

screen shot your set up screens and ballistic screens, we will find the issue

The bullet data was picked off of the ballistic apps menu.

Regardless of the app, the real world shooting dope is what seemed to be way off, not really the app. The 100 yard zero is good. We are required to confirm at the range I go to. I double checked the torque on the scope rings. Possibly an internal scope problem?

 

[Lowlight]

where is your range card,

There have to be missing pages because 2100fps on you MV should not be anything of value and your BC is easily a 3000fps BC

Give us the shooter screens too

 

[Lowlight]

Give us what you shot to HIT 600 and 750 and what the computer now says to compare

 

[orientalexpress]

where is your range card,

There have to be missing pages because 2100fps on you MV should not be anything of value and your BC is easily a 3000fps BC

Give us the shooter screens too

Sorry, the MV would normally have read 2628fps. the 2100fps number is the number it spit out AFTER i did the "calibration". Once

Give us what you shot to HIT 600 and 750 and what the computer now says to compare

Ballistic App 600=4.1mils, 750=5.9

Date 7/14
Actual impacts 600=4.55, 750=6.6


Date 7/21
Actual impacts 600=6.6, 750=9.4

 

[Lowlight]

Sounds pretty impossible to go from 5.9 Mils or even 6.6 Mils to 9.4

Either your scope broke, you shot a different set of targets, or something else happened.

None of that makes any sense, I would throw your data out and start over by doping the rifle correctly first and then truing the computer.

9 Mils with a 6.5 at 2625is closer to 1000 yards

These numbers are close to right, didn't say which 140gr bullet so I picked a generic one. this data is closer to right

There is a lot more happening here than meets the eye

 

[orientalexpress]

Sounds pretty impossible to go from 5.9 Mils or even 6.6 Mils to 9.4

Either your scope broke, you shot a different set of targets, or something else happened.

None of that makes any sense, I would throw your data out and start over by doping the rifle correctly first and then truing the computer.

9 Mils with a 6.5 at 2625is closer to 1000 yards

What's really strange is my friend has the same model rifle with a 3" longer barrel. Same caliber, same gun, same load recipe. We both got similar differences from week to week, with similar results. I guess I should note that we're shooting light weight 6.5 hunting rifles in 18" and 21" for an endurance style match.

I actually took about 3 shots at 1000 (6'x6' steel plate with a 10"x10" center) with the "calibrated" data which was 15.1. The elevation was very close, the windage needed a little work at around 18" off of the 10x10 to the right.

 

[Lowlight]

I have seen SNELL's Law cause about .5 of difference in data at 1000 yards, in heavy mirage and with forward direct sunlight

But 3 Mils is crazy big.

 

[Dthomas3523]

Yup, something is broken or confused.

3mil swing isn’t really possible.

 

[2aBaC̶a̶]

Interesting that 2 separate rifles would have the same issue. You mentioned reloads. What recipe are you using? If the only common factor is ammo, I wouldn't count that out.

maybe try a box of factory ammo on your next outing to eliminate the possibility of it being a reloading issue.

 

[Diver160651]

Let me take a swing at this because your curve using your data on 7/21 seems to indeed indicate that your running ungodly slow, but also as expected for those types of speeds at those distances. Give or take, the curve actually works. for velocities in and around the 2150-2170

600=6.6
750=9.4
1000= 15.1
Let's not even sweat the BC issue or the .5 mil because at your chrono'd speed and your dope @ 600 thru 1000, is far off. Here is the real thing to focus in on. . you are off by at least 6 mils from your first chrono read @ 1000.

I would usually be really really suspect your true zero, range, or scope but because the 7/21 curve lines up with itself and because you both had similar results, lets just toss the scope and normal stuff aside for now and focus on the possibility that you really messed up your reloads. Maybe you used the wrong powder in some, but my guess might be that you loaded some as you should and the other part of the batch with a stuck scale or other brain fart.

Go ahead and box test your scope, confirm range, that never hurts to cover the usual suspects.

This is so far from what is expected out of a 6.5 even n a short barrel, I would stop.

Get factory ammo, rezero exactly how the gun will be shot. Don't zero with a barrel mounted device. Chrono the loads and reshoot.

 

[Diver160651]

Interesting that 2 separate rifles would have the same issue. You mentioned reloads. What recipe are you using? If the only common factor is ammo, I wouldn't count that out.

maybe try a box of factory ammo on your next outing.

Ha... was typing as you posted.. I agree factory ammo before going anywhere else.

 

[orientalexpress]

Interesting that 2 separate rifles would have the same issue. You mentioned reloads. What recipe are you using? If the only common factor is ammo, I wouldn't count that out.

maybe try a box of factory ammo on your next outing to eliminate the possibility of it being a reloading issue.

I would usually be really really suspect your true zero, range, or scope but because the 7/21 curve lines up with itself and because you both had similar results, lets just toss the scope and normal stuff aside for now and focus on the possibility that you really messed up your reloads. Maybe you used the wrong powder in some, but my guess might be that you loaded some as you should and the other part of the batch with a stuck scale or other brain fart.

Go ahead and box test your scope, confirm range, that never hurts to cover the usual suspects.

This is so far from what is expected out of a 6.5 even n a short barrel, I would stop.

Get factory ammo, rezero exactly how the gun will be shot. Don't zero with a barrel mounted device. Chrono the loads and reshoot.

Hornady ELD-M 140gr. H4350 (edit:41.7 gr). Loaded to eld factory length. Without looking up its whatever the OAL of factory 6.5 eld-M is. I have all of my relatively small reloading items in a plastic bin with a lid. There are 2 pistol powders some 4064 and some 4350. Now I'm not 100% i didn't mix up the 2 rifle powders but I am about 99.99999% sure. I am 100% i didn't load with pistol powder. I think I would have noticed the blue label vs the black label and I just opened the can of 4350 when I loaded these 40 rounds.

Also my buddy loaded his own to the same spec. THat's what's so weird about it.

I didn't shoot all of the 40 rounds i loaded. So I might load up 10 and take them out to compare along with a box of factory ammo.

 

[Diver160651]

For what it is worth, my normal 140 6.5cm load with h4350 is around 2850, and 3025 with 123s. But I down load and use cheap round nose low BC Spears $18 per 100. These I use to practice wind as I am running them at 2200fps.

Point being, it is entirely possible to not put enough powder in and get very slow velocities. I am just putting that out there.. I don’t think it is aliens ? but who knows at this point.

 

[orientalexpress]

Update: Went out to the range this past weekend with the remaining rounds from the previous trip and 30 freshly loaded rounds. While checking my zero at 100, discovered it was something crazy like 8 mils high. I was completely puzzled, but once rezeroed it was very very close to the dope my ballistic app was spitting out up to 500. I think I've ruled out undercharging or using the wrong powder as the loads from previous and the fresh ones shot approximately the same. I pulled a few of them just to double check. After talking to the manufacturer's customer service tech on the phone I think I either have a bad scope or I didn't tighten the turret caps down enough and when I was dialing it was slipping and moving poa. He suggested that I pull the turret cap and remove the numbered zero disk to see if there's any drag marks in there indicating that the set screws were sliding. I'm going to check it when i get home.

 

[seansmd]

Update: Went out to the range this past weekend with the remaining rounds from the previous trip and 30 freshly loaded rounds. While checking my zero at 100, discovered it was something crazy like 8 mils high. I was completely puzzled, but once rezeroed it was very very close to the dope my ballistic app was spitting out up to 500. I think I've ruled out undercharging or using the wrong powder as the loads from previous and the fresh ones shot approximately the same. I pulled a few of them just to double check. After talking to the manufacturer's customer service tech on the phone I think I either have a bad scope or I didn't tighten the turret caps down enough and when I was dialing it was slipping and moving poa. He suggested that I pull the turret cap and remove the numbered zero disk to see if there's any drag marks in there indicating that the set screws were sliding. I'm going to check it when i get home.

8 mills or 0.8 mills high?

 

[orientalexpress]

8 mills or 0.8 mills high?

8 mils. I was shooting over 5x5 steel sight in plate into the berm.

 

[2aBaC̶a̶]

Did you adjust your buddies scope also? How do you explain both of you having the same issue?

 

[orientalexpress]

Did you adjust your buddies scope also? How do you explain both of you having the same issue?

He didn't come with me this last trip. After discussing/texting back and forth all week I found out his dope wasn't near as off as mine. It was still a difference of a mil at 600. Which still seems like alot to me but not near as drastic as what I was seeing.

I also inspected the disk that the external turret screws bite onto when you tighten them. No drag marks, but the tech I spoke with mentioned that you should be able to a little divot/ding where the screw contacts the disk. I didn't see any kind of marks, so I'm wondering if the screws just weren't tight enough. I remember tightening them snugly but didn't want to strip them out, perhaps they need to be just a big on the tighter side.

 

[seansmd]

He didn't come with me this last trip. After discussing/texting back and forth all week I found out his dope wasn't near as off as mine. It was still a difference of a mil at 600. Which still seems like alot to me but not near as drastic as what I was seeing.

I also inspected the disk that the external turret screws bite onto when you tighten them. No drag marks, but the tech I spoke with mentioned that you should be able to a little divot/ding where the screw contacts the disk. I didn't see any kind of marks, so I'm wondering if the screws just weren't tight enough. I remember tightening them snugly but didn't want to strip them out, perhaps they need to be just a big on the tighter side.

You may want to share where you are shooting and see if someone can go help you at the range. +8 mils could be very dangerous depending on the range setup. You said above it was hitting the berm, so that is good!