DOPE/drop chart data.

[Formidilosus]

I'm not sure what's so hard.

6 MPH base wind for 7RM with 162 ELDX - using minutes of angle
100= 0.25
200= 0.50
300= 0.75
400= 1.0
500= 1.25
600= 1.5
700= 1.75
800= 2.0
900= 2.25
1000= 2.5

Without a ballistic calculator, how are you determining what wind speed matches different bullets?




So took both skilled MOA users, and skilled mil shooters and ran timed wind call exercises using that technique against mil wind bracket.

So uneven ranges, varying wind speeds, varying wind angles. Using the above method resulted in an average wind call development of +/- 5 seconds slower for the MOA users versus the mil users. It also resulted in three times the amount of errors that were .25 MOA or larger, compared to mils that were .1 mil or more off.



I never said one could come up with a way to make a wind call with MOA. I said, there isn’t an equivalent MOA wind system that is as clean, simple, correct, and easy to use across all ballistic profiles. This isn’t a guess. There are multiple places that have and continue to try to find a way to do MOA that works as well as mil wind brackets.

 

[Formidilosus]

As an aside.

I hear a lot of guys say they don't dial wind, but on the initial shot I really don't understand why you wouldn't. The typical mil reticle is going to have 1 mil or .5 mil subtensions. How are you holding an accurate .3 mil or .7 mil hold?

If you can spot your shots, I get making a quick wind hold adjustment but it seems more precise to dial wind on the first shot.

I can dial 7 clicks, can't hold .7 mil...precisely anyway.

How much time do you have with mil reticles, field shooting under time constraints, and have you ever had modern training on the system?

A mil reticle with .5 mil increments can be consistently and correctly broken down into .1 mil increments visually, with a .05 mil precision by new users within 10-15 minutes of practice.


We hold wind, because in field conditions wind holds change rapidly. If I dial wind, and then get a wind shift while prepping for the shot- do I come off the gun to redial? Wait for the wind to be correct for the dialed solution? No. Dial elevation, hold wind. That allows one to instantly make a wind call correction if needed.

 

[Ratbeetle]

How much time do you have with mil reticles, field shooting under time constraints, and have you ever had modern training on the system?

A mil reticle with .5 mil increments can be consistently and correctly broken down into .1 mil increments visually, with a .05 mil precision by new users within 10-15 minutes of practice.


We hold wind, because I’m field conditions wind holds change rapidly. If I dial wind, and then get a wind shift while prepping for the shot- do I come off the gun to redial? Wait for the wind to be correct for the dialed solution? No. Dial elevation, hold wind. That allows one to instantly make a wind call correction if needed.

You certainly are full of yourself, aren't you?

Extensive. Mil/mil is all I shoot and all I've ever shot. I'm not talking a PRS match, I'm talking a hunting situation where you locked down on an animal. You're telling me that it's just too difficult to reach your right hand up and twist three times before squeezing off your typically one and only shot?

If I have enough time to exstensively "prep" for a shot I have enough time to dial a slight correction for a shift. This isn't a 10 shot course of fire where a guy is moving between stations that might take 5 minutes.

A miss would be a different story. If I spot the shot, I'll make a wind hold.

And you might be able to break down .5 mil subtensions into .1 mil increments visually but it's not going to be more precise than dialing.

 

[amassi]

Tag

Sent from my SM-G892A using Tapatalk

 

[BCD]

So how does one determine the wind bracket for a particular bullet and caliber (I'm using Mil scopes)?

Thank You!

 

[lkwoolsey]

So how does one determine the wind bracket for a particular bullet and caliber (I'm using Mil scopes)?

Thank You!

Gotta go shoot in various wind conditions and keep a log of how your bullet behaves. The army taught us a basic formula, but that's using a specific bullet. Best way is to go shoot and keep track.

 

[Formidilosus]

So how does one determine the wind bracket for a particular bullet and caliber (I'm using Mil scopes)?

Thank You!

The first number of the bullets G1 BC is generally correct.

Gotta go shoot in various wind conditions and keep a log of how your bullet behaves. The army taught us a basic formula, but that's using a specific bullet. Best way is to go shoot and keep track.

I do not need to shoot in various winds to know what the bracket is.

So, your argument why one is better than the other is that you know a guy that is slow and makes mistakes compared to a different guy you know that is not as slow and makes less mistakes? It sure is hard to argue against hard facts like that.

I didn’t say “a guy”.

Yeah, you right- I don’t understand MOA.

 

[tm7554]

One thing i'm not following for the MIL example is the rate of drift per 100 yards. On an 800 yards shot the velocity on the first 100 yards is greater than that of the last 100 yards (ex. 3000 fps at muzzle and 1850 fps at 800 yards). So how can the wind drift be the same for each 100 yard increment even though the velocity is not? Feel like i'm missing something here.

 

[Reburn]

One thing i'm not following for the MIL example is the rate of drift per 100 yards. On an 800 yards shot the velocity on the first 100 yards is greater than that of the last 100 yards (ex. 3000 fps at muzzle and 1850 fps at 800 yards). So how can the wind drift be the same for each 100 yard increment even though the velocity is not? Feel like i'm missing something here.

Your thinking a mil is the same at 100 yards as at 800 yards. A mil or moa is bigger the farther out you get.

You will understand better when you figure out how many inches a 0.1 mil is at 100 yards and a 0.1 mil at 800 yards.

 

[tm7554]

No I understand that, I’m purely looking at the rate of drift shown on their bracket. It’s the same for the first few hundred yards as it is the last. Yet, the project has lost probably at least 1000fps at those distances. Meaning the projectile spends more residence time in the wind from 700-800 yards than from the muzzle to 100 yards. Yet the drift in mils is the same?

 

[tm7554]

406smth thank you

 

[Reburn]

Well again. The value for a 0.1 mil at 100 yards is 0.36" and at 1000 yards is 3.6". So while the drift only increases by 0.1 mil the value of 0.1 is increased by the yardage as well.

So for every tenth of a second the bullet spends from 700-800 yards the value for the 0.1 mil has increased in the same manner.

Other then the loose understanding on how and why it works that I have above I can tell you the first number for the G1 BC is pretty damn close to lining up across all my boolits and speeds for all my guns.

 

[Texasbuckeye]

I plugged my bullet data into a ballistic calculator and simply changed the wind speed to see what my “wind bracket” is for my bullet and estimated factory round MV. I found 5.5mph gave me a 0.1mil per 100 yard bracket out to 800 yards. Of course this may change slightly if I find my MV considerably lower than listed, tho I find that hard to fathom it would be low enough to effect windage.

Edit: prior to reading this post I had no concept of the wind bracket. This is why I love reading practical stuff on these boards that can make life simpler. Thanks rockslide forum!!