I'm trying to figure out how to do this in my head. I dont have a chronograph but I would like to create a drop table. I'm going to a 600 yard range soon, and would like to perhaps gather some data there. My thought would be to record drops at the known distances on the range from 100-600 yards and then plot them in Excel, then obtain a function that I could then use to extrapolate to longer distances. Also, I have FTE for my Iphone, and was thinking another way to get there was to record my actual drops and then try to fit it to a firing solution in FTE by adjusting the muzzle velocity input. Anyone want to chime in?
Range Report Drop Table Without a Chronograph
- Thread starter Domestique
- Start date
Re: Drop Table Without a Chronograph
Is this reloads or factory ammo?
Terry
Is this reloads or factory ammo?
Terry
Re: Drop Table Without a Chronograph
Reloads...
Reloads...
Re: Drop Table Without a Chronograph
I doubt you're going to find a function for Excel that comes close to the calculations used in JBM (or, by extension, FTE). But I do think you can take your dope for several ranges out to 600 and either adjust the muzzle velocity or leave it alone and play with the BC to see if you can fit your drop curve.
I doubt you're going to find a function for Excel that comes close to the calculations used in JBM (or, by extension, FTE). But I do think you can take your dope for several ranges out to 600 and either adjust the muzzle velocity or leave it alone and play with the BC to see if you can fit your drop curve.
Re: Drop Table Without a Chronograph
That's how i do it. Not that it is right, but works for me. My Chrono's not accurate anyways. I shoot a 7wsm with the Berger 180 lvd's. So i use Brian's G7 BC so i know that is a good number. I have Bulletflight on my Itouch. I input a speed that i got shooting over the chrono or one that i think is close. Then i put my steel target somewhere around 700 yards to start with. Dial up the MOA that the Bulletflight says with the conditions off my Kestrel 3500. Have a spotter there to see where your hitting if its off the target. Make scope adjustments till you are on target and write down the changes. Then go into the program and change the muzzle velocity till your drop matches your dope. Then if you have room move the target out to 1000 yards or so. You should be closer now too your real dope once you shoot. Once again make changes till you are on target. Then change MV to match up with your dope. For me its just a small change at 1000 and my 700 really does not change. I found i only need these two points and i am good to go. Also the longer the range you can get for the second shot the better. Then from 700 yards in everything is dead on. I don't think that 600 yards is far enough out too get good data. Try 400 and 600 for your two spots. Then when you can get longer range you will be really close if not on. I have done this same thing with 4 other gun. 7wsm was dead on first shoot, but the others took a little more tweaking. I think this is because i only shoot Berger bullets, and trust all of Brain's BC numbers to be dead on, so all i have to adjust is MV. I have not shoot any other bullet brand so i really cant say. Hope this helps.
That's how i do it. Not that it is right, but works for me. My Chrono's not accurate anyways. I shoot a 7wsm with the Berger 180 lvd's. So i use Brian's G7 BC so i know that is a good number. I have Bulletflight on my Itouch. I input a speed that i got shooting over the chrono or one that i think is close. Then i put my steel target somewhere around 700 yards to start with. Dial up the MOA that the Bulletflight says with the conditions off my Kestrel 3500. Have a spotter there to see where your hitting if its off the target. Make scope adjustments till you are on target and write down the changes. Then go into the program and change the muzzle velocity till your drop matches your dope. Then if you have room move the target out to 1000 yards or so. You should be closer now too your real dope once you shoot. Once again make changes till you are on target. Then change MV to match up with your dope. For me its just a small change at 1000 and my 700 really does not change. I found i only need these two points and i am good to go. Also the longer the range you can get for the second shot the better. Then from 700 yards in everything is dead on. I don't think that 600 yards is far enough out too get good data. Try 400 and 600 for your two spots. Then when you can get longer range you will be really close if not on. I have done this same thing with 4 other gun. 7wsm was dead on first shoot, but the others took a little more tweaking. I think this is because i only shoot Berger bullets, and trust all of Brain's BC numbers to be dead on, so all i have to adjust is MV. I have not shoot any other bullet brand so i really cant say. Hope this helps.
Re: Drop Table Without a Chronograph
You should be able to get the BC for your bullet from the manufacturers website.
You should be able to get the BC for your bullet from the manufacturers website.
Re: Drop Table Without a Chronograph
There are a couple manufacturers whose BCs I'd trust (Lapua, Berger) but others have been off quite a bit from what Litz' tests got).
If you do have a reliable BC, just adjust the muzzle velocity until it matches the results you're getting.
There are a couple manufacturers whose BCs I'd trust (Lapua, Berger) but others have been off quite a bit from what Litz' tests got).
If you do have a reliable BC, just adjust the muzzle velocity until it matches the results you're getting.
Re: Drop Table Without a Chronograph
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 19Scout77</div><div class="ubbcode-body">Go buy a chrono. It is a SMALL price to pay for ALOT of benefit. </div></div>
+1. Especially if you reload. Reloading without a chrono is like eating your ceral without the milk. It can get a little crunchy. People who reload and dont use a chrono are only hurting themselves and wasting there money and time.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 19Scout77</div><div class="ubbcode-body">Go buy a chrono. It is a SMALL price to pay for ALOT of benefit. </div></div>
+1. Especially if you reload. Reloading without a chrono is like eating your ceral without the milk. It can get a little crunchy. People who reload and dont use a chrono are only hurting themselves and wasting there money and time.
Re: Drop Table Without a Chronograph
You can try this ballistic program. Vary the velocities until it matches your data. JBM Ballistics
You can try this ballistic program. Vary the velocities until it matches your data. JBM Ballistics
