bullet and wind drop charts

[crowsnest2002]

I made this and two other bullet drop charts today for 30degrees, 60degrees, and 90degrees. Can you guys think of anything I should add. I have the yardage marked where the bullet becomes subsonic. Since it's not for hunting purposes I'm not really worried about retained energy. This is for the savage f/tr 308, not for hunting (well maybe a groundhog once and awhile ) If you have some custom drop charts I'd like to see them. Also all the data was collected from using the websites ballistic calculator which is really nice once you play with it.

 

[FearNoWind]

I don't see the elevation on your drop chart. How far are you above sea level?
From what I see you used G1 BC data. the Nornady Amax is a scenar shaped bullet so I'd recommend you run the numbers again using G7. For the MV you list I'd figure the G7 BC to be close to .218 - .219.

 

[crowsnest2002]

Your right, duh should have gone with the g7.

 

[7magcreedmoor]

Quick question: why did you print the drops and windage in inches? Unless you have some trick I haven't heard of, you are making more work to use the info converting drop in inches to clicks or moa @ whatever distance the shot happens to be. If you print your drop chart in whatever the adjustment increment your scope happens to be calibrated in, your work goes much faster in the field. As an example, my scope is MOA turret and reticle. I lase the target, read the drop in MOA off the chart, dial same and shoot. No math. Just wondering...

 

[FearNoWind]

Crowsnest2002,
Just a guess, but are you relying on a mil-dot reticle? The "inches" thing prompted my question. I know when I began with mil-dot reticles I found it easier to print drop charts using inches because I could calculate how many inches were represented by the dots and easily multiply that by yardage to select my aim point. It was clumsy (and my fellow shooters told me it would be) but it worked until I retrained my brain to handle MOA.

 

[crowsnest2002]

Honestly I would like to retrain myself to use MOA. I think it would be better if I did. Any good reading material for an MOA conversion? Maybe some things you read that helped you take the big step.

 

[Barrelnut]

Honestly I would like to retrain myself to use MOA. I think it would be better if I did. Any good reading material for an MOA conversion? Maybe some things you read that helped you take the big step.

It's incredibly simple:

100 yards - 1 MOA = 1"
200 yards - 1 MOA = 2"
300 yards - 1 MOA = 3"
400 yards - 1 MOA = 4"
500 yards - 1 MOA = 5"
600 yards - 1 MOA = 6"
600 yards - .5 MOA = 3"
600 yards - .25 MOA = 1.5"
etc.

Works great with a MOA/MOA scope. For example at 600 yards a scope with 1/4 MOA clicks would be 1.5" per click.

 

[Wedgy]

1 moa = 1.047"

 

[Barrelnut]

1 moa = 1.047"

Of course it is. But that is only .282 inch difference at 600 yards. I can't quite shoot that accurately. So I round down to 1 inch.

 

[Engineering101]

Barrelnut

You slipped a digit. As you noted, the difference between MOA and inches is 4.7%. A typical dialup at 600 yards depending on your rifle will be 50 to 60 inches. If you are off by 4.7% that will be about 2.5 inches. I'm not willing to add that kind of error if I don't have to.

 

[Barrelnut]

Barrelnut

You slipped a digit. As you noted, the difference between MOA and inches is 4.7%. A typical dialup at 600 yards depending on your rifle will be 50 to 60 inches. If you are off by 4.7% that will be about 2.5 inches. I'm not willing to add that kind of error if I don't have to.

Thanks for correcting. It is .282 inches difference PER MOA. So if 12 MOA were required for 600 yards the difference would be 3.38 inches. OMG, that's a little over 1/2 MOA.

This is why I only use my app. Bad at math.

 

[crowsnest2002]

Hey, we're all here for each other and we all learn from our mistakes . That is why I like this site. People are full of information and not afraid to just explain without insult. I am still doing the inch method for now. Thanks for all your input and I'll try to get a little better with moa.

 

[7magcreedmoor]

Hey, we're all here for each other and we all learn from our mistakes . That is why I like this site. People are full of information and not afraid to just explain without insult. I am still doing the inch method for now. Thanks for all your input and I'll try to get a little better with moa.

I would recommend Bryan Litz's book "Applied Ballistics" to anyone seeking a better understanding of this subject. He deals with both theory and practical use in layman's terms, without leaving out anything important. Here is my own "short version" of basic rifleman's scope use keys: The optics we use are calibrated using angular measurements, either minutes of angle, or milliradians. It doesn't really matter which you choose, it is basically a personal preference issue- they are both doing the same thing in the end. I like minutes of angle (MOA) because, well, that's what I like. The important thing is, whichever system you choose, get a scope with the same system in turret and reticle. In other words, if you like a mildot reticle, make sure you have turrets that are calibrated in MILs (usually they will adjust in 1/10th mil per click), or if you like MOA, you want turrets and reticle to both be graduated in MOA (turrets are often 1/4 MOA per click). Having made your choice, print your drop charts in the same unit of measure. When you determine the range to the target (hopefully with a laser rangefinder, but optical measurements can also be used- subject to considerable opportunity for user error), you then consult your drop data, and dial the appropriate MOA or MIL setting. The windage should also be given in the same unit, again so you can dial or hold without having to engage in math conversions on the spot. I had a very difficult time convincing a friend of mine to stop trying to think of everything in inches, which was making his life so much harder when trying to dope the shot in the field. He has finally come around to this simpler approach. I personally go one step further in simplifying the process, and that is having my turrets engraved with the actual range data in addition to the MOA, but I don't want to rush you...

 

[crowsnest2002]

yes, I've always wanted to get his book. I'm sure I'd be the only one reading it in the house. Maybe I can hint around to my wife about it.