Thread: Drop chart help

Hi all,

Looking for a bit of info for creating a drop chart for my short 308 with reloads.
Iv done a simple ladder test to find a decent consistent load. Shooting 150gn interlocks with 44.5grains 2206H. Currently have a 100m zero but upon doing some research I’m thinking a 200m would be best for apparently being able to point and shoot out to 250m ish potentially.
At this stage around 320m would be my furtherest shot id need to take and also be comfortable with.

Is it best I borrow a chronograph to workout muzzle velocity etc then use the Hornady app for example to figure out the drops?
Or forget the chrono, access a 200m range to zero rifle then do some shooting at different distances to gauge where the projectile is landing?

Being in Auckland the closes 300m range is the NZDa one in Tauranga.

Thanks for and info and help.
James

work out muzzle velocity if you have a dial up scope.

Hornady 4dof is really good for a relatively simple end user interface but no different to anything else, bad data in bad data out.

Being able to "point and shoot" is gonna depend on your muzzle velocity & how good the projectile your using is. And the type / size animal your shooting obviously.

If it was me, i would use a chronograph so you can see what you MV is. Hornady has the 150gr interlock data in the 4dof app so you can then use the app, put in all the relevant data the app requires along with the MV and it will give you the information your looking for. Obviously you would want to test at the range & verify but ive found it to be pretty damn close if you dont fudge any of it and take the time to put the correct data in.

From that you could play around with the zero range in the app and see which zero will work best for what your trying to achieve.

I would still make a tall target and verify it with at least 3 ranges.

too easy to do...will post link to pointblank...put in what you know,best guess the rest and tootoo with velocity till it fits....then tootoo with zero range till you have what looks best for you and sight in at that from there on in.

https://www.huntingnut.com/index.php...intBlankOnline

Greetings,
For me it is absolutely essential to have your actual velocity and prepare your drop chart from that, I use the Hornady app for this. 44.5 grains is a mid load and should give around 2,700 fps in a 20 inch barrel based on my own chronographing. Subtract 25 fps per inch below that but to know what you are actually getting chronographing your load in your rifle is the only way to be sure. You may wish to zero a little closer to keep you mid range trajectory down. Your Hornady drop chart will show how much this is. My .308 is zeroed for 172 metres, a handy distance here at home and my standard load chronographs around 2,750 fps. My .223 and 6.5x55 are zeroed at 200 metres. I shot 300 yards (275 metres) recently with the .223 and the drop was close to dead on. You want to have a zero that allows you to take a shot out to your comfort range without faffing about with a range finder. Only you can decide what that is. By all means test your drop chart with actual firing but the drop chart should come first and for that you need the actual velocity.
Regards Grandpamac.

FFS .. think about what youve just typed GPM......
your last 3 lines.....
now go and play with your programme and change velocity by 100fps...and range by 50 yards....you are guessing after all.
the WHOLE POINT of the old rule of 3...3" high at hundred yards was to allow point n shoot out to 300ish yards without fluffing around...and you DONT NEED EXACT numbers for it to work....
I would argue BY ALL MEANS print up a drop chart off the computer but validate on paper to confirm
of just sight rifle in and have rough idea of what drop you are going to have at your roughly guessed range...below 200 yards unless you using something really slow its not going to matter.

that will give some idea of what pointplank looks like and what I mean about changing zero to suit.

[QUOTE=James--03;1404849]Hi all,

Looking for a bit of info for creating a drop chart for my short 308 with reloads.
Iv done a simple ladder test to find a decent consistent load. Shooting 150gn interlocks with 44.5grains 2206H. Currently have a 100m zero but upon doing some research I’m thinking a 200m would be best for apparently being able to point and shoot out to 250m ish potentially.
At this stage around 320m would be my furtherest shot id need to take and also be comfortable with.
Or forget the chrono, access a 200m range to zero rifle then do some shooting at different distances to gauge where the projectile is landing?

yip run with this idea....

Either way is no doubt going to get you a result that will likely do the job, however i would argue that if you can easily get access to a chronograph it would be well worth doing. Even if you dont end up using that info for a drop sheet, its still going to be useful information knowing what your actual MV is and that your SD is good with that load you have come up with. Then you will know if its going to be consistent on those further shots & have a good gauge of how much energy it has out there too.

do you have a rangefinder?
yes its the best to run it over a chroni, theres a forum chroni if you cant russle one up locally

these last few steps take all of a few minutes to do and really take all the guestimation out of things

320m depending where you zero may be easy enough to guestimate based on shoulder shooting and using the back bone as a reference, till you are up and going with all the data youll need to do a drop chart

You can borrow my Crony if close - just a Caldwell but works good.

I’ve never had a Chronograph but am fortunate to be able to verify on a large plate at 565yds.

I zero at 100yds.

Gestimate velocity and put it into my app to get me onto the plate.

Tutu with the velocity to get the right dial up reqd to get on the bull and save it.

Drop chart done.

No reason you can’t do the same with 100 yd zero and verify at 320 on a tall target ? Unless I’m missing something.

B