Range Report not getting correct trajectory data...

[farshot83]

I've been using "shooter" on my android which I really like but I can't seam to get accurate ballistic data. I input the right data but get incorrect results. Should i input my calculated BC based on my environment? Doesn't the program change the BC for its data based on the environment?

For example.
I zero the rifle at 100 then shoot to 400 yards holding on center mass and I get no recordable bullet drop. If I adjust the scope as shooter says I always have high POI vs POA. I love the flat shooting rounds but I want correct data. Any ideas?

Rifle:
Rem 700, 7mm rem mag. Not modified.

Ammo:
winchester brass fired 12x only neck sized
CCI#250 primer
65gr, IMR 7828
Sierra #1915, Matchking, 150gr HPBT

Environment:
Altitude, 7400 feet
Temp, 35-65
Humidity, 30-50
Etc...

Is it just the program or do I need to modify certain parameters? Been messing with it for some time now and am at a loss for an explanation.

 

[farshot83]

Thank you for the quick response.

I know its not physically possible to get zero drop. My scope is not even worth mentioning but it holds up to the recoil.

My target hasn't been very standard...roughly 4 inch steel plate.
My last 5 shot group was 3004-3014fps and the temp was 51.

I know the air density is roughly 20 percent thinner in my environment but shouldn't I see about a 4 inch drop?

Apologize for my questions? Battling frustrations as you can tell. I'm going to mess with the numbers some more. I'll get better prepared and provide more accurate information with paper bulls from a benchrest setup. Thanks again.

 

[1time]

You should be getting about 4.8 moa which is just over 20" of drop going from 100 yards zero to 400 yards.

 

[farshot83]

That sounds right for "generic sea level data" but with my density altitude of 8000-12500 that isn't even close. I grew up in the Midwest shooting deer in Wisconsin and expected that performance but here in Wyoming with the thin air even holdovers for wind (20mph avg by 1pm) are way off. I recalculated the sierra published BC data and found my environmental BC to be over .600 instead of about .430. When I changed this in shooter it was still giving me incorrect click counts.

They use lab conditions to get their data so its not completely useful. I'll run a new set of formulas and manually plot data to find true ballistic data to match and repeat my results. Thanks.

 

[farshot83]

I floated and bedded it and threw a cheap scope on to test it out. Then ballanced it by adding lead to the buttstock and brought the weight up to 12lbs. Used to cary an M249saw in Afghanistan so I don't mind the weight. Factory ammo gave me about 2 inch group with a 200 zero and 5 at 200 yards but my handloads loaded .008 off the lands gives me .5 inch group of 5 shots at 200 yards using the load data I posted. I shoot at 6 power with a seasoned benchrest shooter spotting for me. Even with my mp40c with my loads at 4.4gr titegroup under 165gr plated I can hit a 6inch steel from 60 yards reliably holding at the top of the plate. Typically the expected impact would be under the plate by 6 inches. I'm getting substantial gains in fps with less powder than what's published as max in all manuals. Not complaining about the rifle but rather the data shooter provides me with.

 

[farshot83]

I usually reserve my criticism for my self first then blame uncontrollable variables. I'm certain I may have input data incorrectly because so many use shooter and its very accurate from what I've read. Regarding the scope, its not spring dampened so I go out past my mark then back in to compensate.

I cut zero corners though. I'm relatively new to the data but not to shooting. I want to get a better understanding of ballistics. I'm certain the fault lies in my numbers. I'll run everything again and if I still have issues I'll post my data and maybe you could help me find the mistake. Thanks again.

 

[Cossack]

farshot, if your rifle is zero at a hundred then there is drop at 400, you never told us how much drop. If you can hold dead center at 400 yards and hit dead center then your rifle is not zeroed at 100. How much drop do you have from 100 to 400?

 

[farshot83]

I know how to zero and I use a range finder for distance, even verified range with a second range finder.
I witness roughly 4 inches of drop.
Shooting angle was less than .5 degree uphill which shouldn't be noticeable but still adds to bullet drop.
I'm not new to shooting but still learning the ballistic data and reloading.

Everything I shoot out here in Wyoming seams to shoot amazingly flat except the 338 which uses a ridiculously heavy bullet. I know I'm getting drop but what I see and what I calculate aren't matching up. I grew up in Northern Illinois and hunted deer in Wisconsin often so I know how my bullet drops. My data was always very accurate out there but I can't find the cause for the inaccuracy here. I just double checked my numbers using JBM online and it states my bullet drop to be just under 20 inches but I'm seeing about 4 inches. I witnessed this via a spotting scope watching my friend shoot my rifle. He's used to this phenomena but I'm still seeking a better understanding which gave up on finding.

I'll post the details when I have a chance to get out to shoot again.
I'll get better data with pictures of the bulls and much more detail.

 

[Darkside-Six]

sounds to me like your scope is not tracking, you said your embarassed to mention what kind it is....chances are it is just a piece of junk that isn't working right.

 

[farshot83]

I could easily blame the horrific scope but...others experience the same phenomena with worthy scopes and multiple cartridges.

For some unforeseen reason I'm not getting typical bullet drop and I can not find a ballistic solution to match my field results.

Anyone else on here near Laramie WY? I'd love to share my confusion.
My friend Rich has been a benchrest competitor for over 30 years and he couldn't find the answer either.
He used his Unlimited class rail gun and came up with the same confusing bullet drop phenomena.

I'll post whatever data I collect in hopes of maybe I simply overlooked something. I'll also build tables and charts to show my results and how it differs from "typical" bullet drop.

Give me a few days or so though because I'm going to shoot flat into an elk heart. Maybe a couple antelope to if I have time.
Been waiting to purchase a NightForce but maybe my impatience will settle on a Burris with external turrets.
Thank you for all the input.

 

[Cossack]

I know how to zero and I use a range finder for distance, even verified range with a second range finder.
I witness roughly 4 inches of drop.
Shooting angle was less than .5 degree uphill which shouldn't be noticeable but still adds to bullet drop.
I'm not new to shooting but still learning the ballistic data and reloading.

Everything I shoot out here in Wyoming seams to shoot amazingly flat except the 338 which uses a ridiculously heavy bullet. I know I'm getting drop but what I see and what I calculate aren't matching up. I grew up in Northern Illinois and hunted deer in Wisconsin often so I know how my bullet drops. My data was always very accurate out there but I can't find the cause for the inaccuracy here. I just double checked my numbers using JBM online and it states my bullet drop to be just under 20 inches but I'm seeing about 4 inches. I witnessed this via a spotting scope watching my friend shoot my rifle. He's used to this phenomena but I'm still seeking a better understanding which gave up on finding.

I'll post the details when I have a chance to get out to shoot again.
I'll get better data with pictures of the bulls and much more detail.

Never said you don't know how to zero. Going off your above post, you said that bullet hits point of aim at 400 without adjustments.
What's the barometric pressure right now?

Edit: something wrong with either: your equipment or you didn't measure the distance correctly.
Difference in drop from sea level to ~12,000 feet at 400 yards is only about 4 inches (sea level drop 25 inches and 12k drop is 21 inches). So something got to give here man.
I would just shoot at the 400 yard target with out adjusting for drop to see where bullet is impacting

 

[farshot83]

30.23 not modified in any way.
22.83 corrected for altitude. (minus 1 in per 1000 feet)

I know you didn't imply that I couldn't zero. Just frustrated with these numbers. Feel like I'm banging my head on a brick wall.

 

[Joop]

How high is your scope centerline over the bore centerline and is this factored in (accurately)? Also, are you using a canted base? It's possible that your bullet is still on an upward arc at 100. Even though you are zeroed at that range, it could be moving upward well beyond that and just starting to come down at 400.

 

[tigerfan_9]

two words......box test. test your scope adjustments b/c if it is not tracking then nothing else matters.

 

[farshot83]

The scope offset is 1.625.
Its some shitty Simmons buckmaster 3x9 that came on a used rifle I bought years ago.

I'll do the box test and add corrections if needed.

Need to zero again anyway because I'm cutting the barrel down 3 inches and adding a thread on custom muzzle brake. Doing this Wednesday and going hunting Thursday so I'll post data in a few days. I need to read about a muzzle velocity calibration tool...

 

[farshot83]

Didn't know the velocity tool was in shooter. Thanks

 

[Ring]

did u true shooter?

 

[farshot83]

Not yet. I cut the barrel down and made a muzzle brake for it. I cut a new crown and have not had a chance to find a new OCW. Once I do that I'll true it in shooter. I messed with it a little and I had to raise velocity well above what I know its close to in order to get similar trajectory to what I actually get. Prior to cutting barrel I did install a friends old weaver 1/8iphy scope which we know is perfect and same results with unrealistic lack of bullet drop.

I know about getting to a velocity tool through the graph but it only lets me add or subtract from velocity. How do I get to that tool shown in your screen shot?
Mine is on android if that helps.

 

[Ring]

make sure u have the up to date version of shooter

 

[farshot83]

I dont have that option in the environment menu for the velocity tool.

Oh well. I'll just build charts. Thanks for the help though.

 

[SAPenguin]

It is possible to have 2 zeros. As someone above mentioned, you could be zeroed at 100 yards while the bullet is still travelling on an upward trajectory. It then levels out and drops back down to zero at 400.

I have experienced this with my AR-15 where a 50 yard zero is also a 200 yard zero.

Just a thought. Maybe shoot at 250 yards, and if you are impacting 3 inches high, you know why

 

[woostri]

The only thing that would explain this to me is if the zero at 100 yards never really happened. Shooter, and any other ballistics program these days, is extremely accurate. They model the bullet flight within inches even out beyond 1000 yards. But they are garbage in/garbage out. It's easy to mess up BC's because the published values are usually inflated but even that wouldn't account for the difference between 4" drop and 21" drop. I'd bet the rifle is actually zeroed at around 350 yards. That would give 4 inches drop at 400.

AIM SMALL MISS SMALL