Drop Chart HELP!!!!!!

[H20FOWL]

I have a Weatherby Vanguard S1 270 WSM and I'm making it my long range gun. I have added a new stock, bedded the entire action, and the barrel is free floated. I have a vortex HSLR 4-16x44. I am looking for a gun to hunt with out to 1000 yards or less and just for fun out further.

Iv loaded my own ammo with norma brass, Barnes LRX bullet’s 129 Gr. using WLRM primers, With H4831powder. I have it zeroed at 200 yards. I shot a group of .531 inches with the load at100 yards














I am using the G7 ballistic calculator on the vortex website.

I have chronograph the the load and with the load I it stated the average velocity was 3110 FPS with a 12 FPS spread. I went to the range and shot a 400 yard and 600 yard 5 shot group. I used the true muzzle velocity formula on the G7 and I was low at both 400 and 600 yards. I averaged the two groups with there height and it came out with 3006 FPS. The heat rays were really bad in the scope I don't know if that had anything to do with it.

I returned that night no rays and shot the same at 400 and 600 yards and was an average of 5 inches high at 400 and 5.8 at 600. I shot at 850 yards and all bullets flew over the target. I returned and calculated the data on the trajectory validation and it showed I was pushing 3262 FPS. That was well over the choreographed data I got.

I went to the range again today and created my new drop chart for the 3262 FPS and verified the 200 yard zero. I went to the 400 yard shot, The chart stated 3.5 MOA of adjustment. I dialed it in and shot the five shot group and great group. I did the same at 600 yards and it stated 8.1 MOA of adjustment. My scope is in 1/2 in MOAs so I Dialed 8 MOA. Again great group. here is a picture of the group.

Target picture

I got it backwards the green dots are 400 and red dots are 600.

I went back to 855 yards and and the drop chart showed 15.1 MOA. I dialed the scope to 15 MOA and shot six shells. After the first three I thought I had a wind drift so I calculated it out and .5 MOA and shot three more. Here is the target at 855 Yards

850 yard target
The shots from 850 yards are way low. One shot was off paper due to the adjustment I made for the crosswind that was not there. The other five are at an average of 12.2 inches low (three below the bullseye are the first three). I used the trajectory validation when I got home from the range and it showed that 3161 FPS was the true velocity. I figured the 400 yard group to be -1 inch low at the four hundred and the trajectory validation was 3186.

Those numbers are not to far off my original velocity with the chronograph. not sure what else to do I’v burnt through a lot of ammo and just want to get it right.

Should I do my furthest yard that I want to shoot and do the trajectory validation off of it first, or whats the best way?

Whats the best way to figure out the avenge drop on the target when you have some holes above and below bullseye. I just based it off the ones below since there was more. Is there a way to figure in both?

Any help would be great. Thanks

Pictures won't upload all attach them as soon as possible

[tangolima]

You said your scope has 1/2 MOA per click. You are sure about that? Most modern scopes have 1/4 MOA per click or finer. That may explain you seem under compensating.

Your load is doing 3110 fps with spread of 12 fps. That's better than 0.3%. Even precision electronic systems would have hard time delivering such precision, let alone chemical mechanical system. Exceptional hand loading techniques!

At 1000 yards every single bit of input will have noticeable effect on the output. I guess the chart just get you close enough for the spotter to call out corrections. You need a good spotter on your 2-man team.

-TL

[emcon5]

I am not familiar with the Vortex calculator, and not willing to register with them to look at it, does it include inputs for altitude and sight height over bore?

Run the numbers in JBM and see if they match the Vortex numbers or reality.

http://www.jbmballistics.com/ballist...culators.shtml

[reynolds357]

For long range shooting, a calculator will give you an idea, but thats about it. You have to physically shoot the shots and build a dope sheet.
1/2 and 1 moa adjustment elevation on tactical scopes is becoming quite common. I have a 1 MOA knob on one of my tactical scopes. Its nice for quick adjustment at shorter ranges, but 1 click = 10" at 1k is pretty un-forgiving.

[overthere]

Plugging in the basic values into JBM (not knowing your ambient temperature, humidity, altitude etc.), it shows a drop of 16.8 MOA at 850 yards with that bullet and a velocity of 3262 fps (from a 200 zero). Quite a lot more than the 15.1 you were dialing. A difference of 1.7 MOA at 850 yards is 14.45 inches which is close to the 12 inches low you were seeing.

JBM has been very accurate in what I have used it for.

[Bart B.]

I don't think a sight correction smaller than 1/3rd the size of the groups you can shoot afield should be made. Otherwise, the change made may not be seen. If you put all fired shots inside 1.5 MOA, 1/2 MOA corrections are minimum size.

[sirgilligan]

Ballistic Drop calculators are only estimates. I wrote the ballistics calculator in my app and I have compared it to many others. The tables for drag adjustments vary, the algorithms vary, the approximations for adjusted air density vary, and there is not one right answer that I know of.

I went to the Vortex site and used their default values to run a calculation. Note that these are not the values for your firearm or ammunition.



Here is the text from my app:

Untitled Ballistic Info
Sight Height: 1.75
Zero Distance: 200
Muzzel Velocity: 3000
Ballistic Coefficient: 0.617
Wind Direction: 12:00
Wind MPH: 0
Altitude: 5,000
Temperature: 41
Relative Humidity: 50
Barometric Pressure: 25.69
Notes:

Range: 1 yds Vertical: -1.7 in
Time of flight: 0.00s, Wind Drift Right: 0.0"
[Velocity: 2999 fps]

Range: 2 yds Vertical: -1.6 in
Time of flight: 0.00s, Wind Drift Right: 0.0"
[Velocity: 2997 fps]

Range: 3 yds Vertical: -1.6 in
Time of flight: 0.00s, Wind Drift Right: 0.0"
[Velocity: 2996 fps]

Range: 4 yds Vertical: -1.6 in
Time of flight: 0.00s, Wind Drift Right: 0.0"
[Velocity: 2994 fps]

Range: 5 yds Vertical: -1.5 in
Time of flight: 0.01s, Wind Drift Right: 0.0"
[Velocity: 2993 fps]

Range: 6 yds Vertical: -1.5 in
Time of flight: 0.01s, Wind Drift Right: 0.0"
[Velocity: 2991 fps]

Range: 7 yds Vertical: -1.4 in
Time of flight: 0.01s, Wind Drift Right: 0.0"
[Velocity: 2990 fps]

Range: 8 yds Vertical: -1.4 in
Time of flight: 0.01s, Wind Drift Right: 0.0"
[Velocity: 2989 fps]

Range: 9 yds Vertical: -1.3 in
Time of flight: 0.01s, Wind Drift Right: 0.0"
[Velocity: 2987 fps]

Range: 10 yds Vertical: -1.3 in
Time of flight: 0.01s, Wind Drift Right: 0.0"
[Velocity: 2986 fps]

Range: 11 yds Vertical: -1.2 in
Time of flight: 0.01s, Wind Drift Right: 0.0"
[Velocity: 2984 fps]

Range: 12 yds Vertical: -1.2 in
Time of flight: 0.01s, Wind Drift Right: 0.0"
[Velocity: 2983 fps]

Range: 13 yds Vertical: -1.1 in
Time of flight: 0.01s, Wind Drift Right: 0.0"
[Velocity: 2981 fps]

Range: 14 yds Vertical: -1.1 in
Time of flight: 0.01s, Wind Drift Right: 0.0"
[Velocity: 2980 fps]

Range: 15 yds Vertical: -1.0 in
Time of flight: 0.02s, Wind Drift Right: 0.0"
[Velocity: 2979 fps]

Range: 16 yds Vertical: -1.0 in
Time of flight: 0.02s, Wind Drift Right: 0.0"
[Velocity: 2977 fps]

Range: 17 yds Vertical: -1.0 in
Time of flight: 0.02s, Wind Drift Right: 0.0"
[Velocity: 2976 fps]

Range: 18 yds Vertical: -0.9 in
Time of flight: 0.02s, Wind Drift Right: 0.0"
[Velocity: 2974 fps]

Range: 19 yds Vertical: -0.9 in
Time of flight: 0.02s, Wind Drift Right: 0.0"
[Velocity: 2973 fps]

Range: 20 yds Vertical: -0.8 in
Time of flight: 0.02s, Wind Drift Right: 0.0"
[Velocity: 2972 fps]

Range: 21 yds Vertical: -0.8 in
Time of flight: 0.02s, Wind Drift Right: 0.0"
[Velocity: 2970 fps]

Range: 22 yds Vertical: -0.7 in
Time of flight: 0.02s, Wind Drift Right: 0.0"
[Velocity: 2969 fps]

Range: 23 yds Vertical: -0.7 in
Time of flight: 0.02s, Wind Drift Right: 0.0"
[Velocity: 2967 fps]

Range: 24 yds Vertical: -0.7 in
Time of flight: 0.02s, Wind Drift Right: 0.0"
[Velocity: 2966 fps]

Range: 25 yds Vertical: -0.6 in
Time of flight: 0.03s, Wind Drift Right: 0.0"
[Velocity: 2965 fps]

Range: 30 yds Vertical: -0.4 in
Time of flight: 0.03s, Wind Drift Right: 0.0"
[Velocity: 2957 fps]

Range: 35 yds Vertical: -0.2 in
Time of flight: 0.04s, Wind Drift Right: 0.0"
[Velocity: 2950 fps]

Range: 40 yds Vertical: -0.1 in
Time of flight: 0.04s, Wind Drift Right: 0.0"
[Velocity: 2943 fps]

Range: 42 yds Vertical: -0.0 in
Time of flight: 0.04s, Wind Drift Right: 0.0"
[Velocity: 2941 fps]

Range: 45 yds Vertical: 0.1 in
Time of flight: 0.05s, Wind Drift Right: 0.0"
[Velocity: 2936 fps]

Range: 50 yds Vertical: 0.3 in
Time of flight: 0.05s, Wind Drift Right: 0.0"
[Velocity: 2929 fps]

Range: 75 yds Vertical: 0.9 in
Time of flight: 0.08s, Wind Drift Right: 0.0"
[Velocity: 2894 fps]

Range: 100 yds Vertical: 1.3 in
Time of flight: 0.10s, Wind Drift Right: 0.0"
[Velocity: 2860 fps]

Range: 125 yds Vertical: 1.4 in
Time of flight: 0.13s, Wind Drift Right: 0.0"
[Velocity: 2826 fps]

Range: 150 yds Vertical: 1.2 in
Time of flight: 0.16s, Wind Drift Right: 0.0"
[Velocity: 2792 fps]

Range: 200 yds Vertical: 0.0 in
Time of flight: 0.21s, Wind Drift Right: 0.0"
[Velocity: 2725 fps]

Range: 300 yds Vertical: -5.9 in
Time of flight: 0.32s, Wind Drift Right: 0.0"
[Velocity: 2593 fps]

Range: 400 yds Vertical: -17.0 in
Time of flight: 0.44s, Wind Drift Right: 0.0"
[Velocity: 2465 fps]

Range: 500 yds Vertical: -33.9 in
Time of flight: 0.57s, Wind Drift Right: 0.0"
[Velocity: 2340 fps]

Range: 600 yds Vertical: -57.1 in
Time of flight: 0.70s, Wind Drift Right: 0.0"
[Velocity: 2220 fps]

Range: 700 yds Vertical: -87.3 in
Time of flight: 0.84s, Wind Drift Right: 0.0"
[Velocity: 2102 fps]

Range: 800 yds Vertical: -125.4 in
Time of flight: 0.98s, Wind Drift Right: 0.0"
[Velocity: 1989 fps]

Range: 900 yds Vertical: -172.3 in
Time of flight: 1.14s, Wind Drift Right: 0.0"
[Velocity: 1879 fps]

Range: 1000 yds Vertical: -229.0 in
Time of flight: 1.30s, Wind Drift Right: 0.0"
[Velocity: 1773 fps]

Range: 1100 yds Vertical: -296.9 in
Time of flight: 1.48s, Wind Drift Right: 0.0"
[Velocity: 1672 fps]

Range: 1200 yds Vertical: -377.1 in
Time of flight: 1.66s, Wind Drift Right: 0.0"
[Velocity: 1576 fps]

Range: 1300 yds Vertical: -471.4 in
Time of flight: 1.86s, Wind Drift Right: 0.0"
[Velocity: 1485 fps]

Range: 1400 yds Vertical: -581.5 in
Time of flight: 2.07s, Wind Drift Right: 0.0"
[Velocity: 1399 fps]

Range: 1500 yds Vertical: -709.3 in
Time of flight: 2.29s, Wind Drift Right: 0.0"
[Velocity: 1320 fps]

Range: 1600 yds Vertical: -857.1 in
Time of flight: 2.52s, Wind Drift Right: 0.0"
[Velocity: 1249 fps]

Range: 1700 yds Vertical: -1027.2 in
Time of flight: 2.77s, Wind Drift Right: 0.0"
[Velocity: 1186 fps]

Range: 1800 yds Vertical: -1222.1 in
Time of flight: 3.03s, Wind Drift Right: 0.0"
[Velocity: 1131 fps]

Range: 1900 yds Vertical: -1444.2 in
Time of flight: 3.30s, Wind Drift Right: 0.0"
[Velocity: 1085 fps]

Range: 2000 yds Vertical: -1696.0 in
Time of flight: 3.58s, Wind Drift Right: 0.0"
[Velocity: 1046 fps]




Here are the screen shots:







Here is a screen shot from another app:



I have found that most of the calculators really start to vary after 300 yards. I do not know which calculator uses the best approximations, models, and algorithms available, but I imagine it is probably an expensive app or device.

My first guess as to what will cause large variations is that hardly is the case that you are shooting at an object that is on the exact same plane as the bore of your rifle, or in other words the target is level with the rifle. There is some incline or decline involved, and that greatly effects results.

[AllenJ]

First zero your rifle at 100 yards. Next shoot a 10 shot group at 300 yards without adjusting scope for yardage, aim at the targets center. Now measure the drop of each shot, add them together and then divide by 10. This gives you the statistical average drop for that load....in those weather conditions at that temperature etc. To use a ballistics program I would do the same 10 shots again, only this time at 500 or more yards, then you can match one of the curves in your program to the actual drop of your load.

Chronographs: Do not trust them. Unless you have spent a lot of money for a premium chrono and you're shooting indoors where the light source is constant, your chronograph is giving you a rough estimate of your bullet speed at best.

My final opinion on what you are trying to do is that you've picked the wrong bullet. I love Barnes bullets but they are not "long range" friendly. Barnes bullets like speed, lots and lots of speed. At 900 yards your bullet is going slow enough that I would guess you'll get very little expansion if any at all.

[Mike / Tx]

Just my thoughts on what your looking at doing and where your at.

For starters I personally would suggest looking at a heavier weight bullet at least in the 140gr range if not more. What you might give up in speed your going to gain in downrange energy and a higher BC to boot. That will not give you a flatter trajectory up close but will carry the speed further than the lighter weight bullet, and make up for some of it further out.

Read through the above real close. You will see several pointers that will help you out in your endeavor. Stuff like finding out your actual drops verses simply guessing at them using a calculator. Been there done that myself many times. The calculators are just like mentioned above, good for getting you close but not actual. Until you know what your load is doing in real life you wil fight with things each time out simply using the calculator. Once you get things dialed in however then you can adjust for your BC which may or may not be what you think it is, as well as your actual velocity. Once you can narrow those things down your findings will become actual data.

When I did the drops for my LR rifle set up I started out with a 200yd zero. I ended up with two 1x12 boards screwed together end to end to get up high enough to catch my bullets once I got out to 800+ yards. As mentioned above you zero and hold the same on the target at each increase in yardage until you get in several ranges to plot your drops from. With my testing I was then able to dial in and make one shot hits on targets out to 1175yds. My best group was 5 shots for 9.5".

I never used it to hunt anything that far out, but it is pure terror on anything 800 and in. There again using heavy for caliber bullets and working on accuracy and not so much on how much powder and how fast I could run them. That is why you see so many of the LR crowd using the heavier bullets. It isn't how fast you have to drive them to get them there, but what they have left over to work with once they do arrive.

Nosler, and Berger have both come out with fantastic bullets in the .277 caliber that should work a ton better for you than the Barnes at the longer ranges. I won't say they will do anything better at 350-400 or under, but those Barnes aren't going to open up much for you, once you get out much past that anyway, or not nearly as good as the others will.

[jmr40]

That bullet is not the best choice for what you want to do. As Mike pointed out it is not a long range hunting bullet, and there are much better choices for target bullets too. I like the copper bullets for hunting, and at moderate ranges they work well as long as impact speeds are fast enough. I wouldn't use one past 400 yards though.

Before you get too far into this I'd start looking at better bullet choices. The bullet you are using has a BC of only .463. A Berger 150 is .531 and the Nosler long range Accubond 150 has a BC of .625

[H20FOWL]

I used the JBM Ballistic calculator and it showed the same was the G7 calculated. Should I start with the furthest yard and work up from there.

I looked at the Nosler long Range but it was not good for up close. Nosler stated it would explode on impact and may not penetrate the animal to where Barnes is a all copper bullet so it will stay together. I may look at the Nosler bullet at a later date but for know i only have the barnes. I walk through trees to get to my long range area and sometimes the 50 yard shot comes available. I have an antelope hunt on sept 13 so not enough time to do another load development.

[AllenJ]

I looked at the Nosler long Range but it was not good for up close. Nosler stated it would explode on impact and may not penetrate the animal to where Barnes is a all copper bullet so it will stay together. I may look at the Nosler bullet at a later date but for know i only have the barnes. I walk through trees to get to my long range area and sometimes the 50 yard shot comes available. I have an antelope hunt on sept 13 so not enough time to do another load development.

I've spent days looking into this and came to this conclusion: There is no such thing as a long range bullet that'll perform well at short range, and there is no short/medium range bullet that'll perform well at long ranges, they just don't make them. Like I said in my post above I'm a huge Barnes fan, my bullet of choice for my 7WSM is the 145 grain LRX but if an animal presents itself much past 700 yards I'm stalking to get closer and not risking making that animal suffer anymore than it has to or just wounding it. When the LRAB came out I was first in line to get some but after reading about their performance at short range they're just range fodder now as I'm not willing to pass up an easy shot in the hope a harder one comes along

Good luck on your hunt.

[emcon5]

Should I start with the furthest yard and work up from there.

If you want a real world drop chart that is 100% accurate, you really need to shoot your rifle at each range and note the actual drop with your rifle.

Realize that if you shoot somewhere else, at a different altitude and different conditions, it won't really apply.

This is why extreme range big game hunting is unethical, and idiotic.

[H20FOWL]

I looked at the Berger bullets and they are not much better BC. The best one is .531 for the 270.

I was looking at Google earth at the area I hunt and the max shot is 700 Yards I don't want to go further than this. I agree I don't want to hurt an animal and make it suffer.

In the G7 calculator I can add the altitude, temp, sp. Will that not make an accurate chart for different elevations as long as i have all the correct data in there with the correct velocity.

[BillM]

Ballistic calculators are to long range shooting what bore sighters
are to short range----close enough to (maybe) get you on paper.

[Mike / Tx]

Ok so with a touch more information you "could" do like I have done many times with a couple of my LR rifles.

You load up a short range load that is great out to 200yds, with a good solid performing bullet like the Partition or Accubond, Interbond or similar type. This gives you the just in case in close shot if needed. Only load one in the chamber when you start through the woods. Granted this load will not be anywhere close to top end velocity, but at 100 through 200 and some yards it groups great and falls only maybe an inch or high at the most from where you have your scope set for the other load. If your dialing your scope for the LR load even better your close in load can be worked into that area when your dial is zeroed.

Once your set up in your LR hunting spot, simply pull that one and chamber the LR round. I have a BR follower installed in my LR rifles so this is pretty easily done. I simply pull one and lay the other in and close the bolt. With the ranges your looking into your not going to find an accurate follow up within reason like you would with a 1-200yd shot. Far to many things cut the odds down unless the animal is down and not moving anywhere.

In the G7 calculator I can add the altitude, temp, sp. Will that not make an accurate chart for different elevations as long as i have all the correct data in there with the correct velocity

The only way you can have your cake and eat it too is to work up your loads using a verified drop chart like mentioned above, where you actually shoot the ranges. Also as mentioned this only works in that altitude, with the current conditions. In order to take the rifle and load elsewhere and expect similar results you would need to verify those drops again at several ranges to adjust for the altitude and current atmospheric conditions.

When we were working up our drops there were folks in other areas shooting the same bullets at the same velocities only they were getting MUCH flatter trajectories, and higher BC's. This was simply due to them being 3000ft higher in elevation than we are here. Not only that but with the added barometric pressures we have here verses what they had we were maxed out several grains below what they were loading. Once you get into reaching out further than around 500yds things change with regard to the loads, and every minute detail will change things a LOT as you get further. It also takes hundreds of rounds testing and practicing before you get a good handle on what to dial up and how much into the wind in order to make that first round hit where you want it to be.

[garyalarson]

Originally Posted by reynolds357

For long range shooting, a calculator will give you an idea, but thats about it. You have to physically shoot the shots and build a dope sheet.

Exactly! You will run yourself ragged chasing your tail trying to get it from any calculator. Build it by hand with confirmed data.

[Jim Watson]

One of our resident LR shooters once posted a method of getting closer than that with calculated external ballistics.

I have always had to do it like most of the guys here, used the charted data to get on the paper, adjust to center, look at the sight setting, and WRITE IT DOWN. I am usually happy to be within a MOA the next time around. But you don't get sighter shots on game. What is your longest actual kill thus far?