Now, I agree there are some holes in the paper, but compared to what Litz is offering in terms of addressing the AJ, I think the outline is way better in many aspects. Will take a new in depth read to see if I can understand it better.
In my opinion, AJ due to crosswind alone is a tricky one, and this formulation makes more sense to me than the one presented by Litz.
Ballistic_XLR is free and works in Excel. It is compatible but not integrated with BfX in any way. What I have for you guys is an advanced ballistic calculation form which allows you to take your shot data and your current conditions and to make a calculated adjustment when the conditions vary beyond what your data is set up to support.
Do you lay your ammo in the sun while you take a shot? Wonder why you get vertical stringing? Do you find that your barrel temperature increasing causes your groups to open up? Do you shoot in variable winds? Do you shoot through multiple barometric pressure zones?
The above and other factors are known to cause groups to open up but they're hard to adjust for. Part of the difficulty rests with how small the changes can be but these changes affect you in lots of ways as well. Using a well developed form that isolates each factor and adjusts for it you'll be able to dope the weather much more effectively.
Ballistic_XLR data sheets (and BfX data sheets) and the Ballistic_XLR calculation form and data sheets are available for download, true enough. I can also provide these as printed items that are printed on Revlar WATERPROOF PAPER. This isn't paper made from wood, it's made from plastic and is 100% water PROOF. It's also abrasion resistant and UV and heat resistant and it is 100% impossible to tear it. The Revlar media made by Relyco and is used by the military. I use 7.7mil media which is about as thick as a playing card.
You can purchase a complete kit with your ballistic data and field grade containment and marking supplies in one of my BADEDS kits, or just purchase the data sheets without all the extra goodies in my B-FEDS set. You can also get the full B-FEDS set or a subset of B-FEDS as a gift for donating to the Ballistic_XLR project.
All of this project is non-profit. It seems the guy that did BfX stepped away from it for a while. While he's dealing with his life and family I'm still around to help out the long range target shooters of the world.
I just finished reading the article for the first time. I have to read it again and compare with other books to come to any conclusion. Basis of the crosswind vertical drift seems to be bit different from what I have red before. Still this article doesn't give tools to solve the actual drift like Litz does. Not taking position at this point if Litz's formula is accurate or not. However the article states to answer three questions.
A) The total bullet drift in a crosswind blowing from left to right is toward 4 o'clock. This is obvious and explained by other references like McCoy and Litz. Article still gives good input on this one.
B) As the crosswind speed increases, the vertical drift of the bullet does not increase as rapidly as the crossrange drift. I didn't catch the explanation for this one at all. Did someone else? I still wonder if this is even true...
C) Crosswind blowing from right to left produces a little more vertical drift than a crosswind blowing from left to right. Author doesn't explain this at all. Just couple of guesses. Same thing goes for this one; I don't know if it is true or not.
All in all those crosswind vertical drifts are so small compared to other deflections that it is really hard to achieve hard facts empirically. Some target shooters tend to jump into conclusions too easily based on what they see on the target. For example very small vertical wind components could lead to conclusions like B and C.
Just finished to read this paper by Mr. MacDonald (Sierra's ballistician) and it makes a lot of sense to me, indeed the formulation presented is much better than the usual "formula" by Mr. Litz (based on a curve fit and Sg)
Last post by meccastreisand - March 17, 2014, 01:26:29 AM
since it's you looking here's some useful info about how it works:
Ballistics Table 0 is the master calculation worksheet. Ballistics Table <temp>_29 are for barometric pressure -1"hg calcs Pocket PC input is the master input worksheet. Everything else cascades down from there.
Last post by meccastreisand - March 16, 2014, 06:32:01 PM
My latest version should have a full set of features for everyone in it but has a couple bits that I think will really affect you guys in a positive way. I've been scanning the BfX forum for things people were wanting and adding those features I didn't already have solved. I did try out the BfX add in and haven't been able to make big wads of it work on my Mac so my spreadsheet does not utilize BfX_xll, just standard Excel features. DO NOT try to open it with OpenOffice or variants thereof. It won't work and you'll call me names while you frustratedly cast about for a way to make it work.
Of particular value are the brand new Primary and Secondary functions tabs and the new Calc Form. With those 3 bits you can calculate proper solutions for highly complex shooting situations including shooting through different atmospheric condition zones, muzzle velocity variations induced by just about anything, predicting MVV based on weather and all sorts of similar things that complicate traditional ballistics solution calculation. The download link above still works.
If you put in correct data it should spit out correct solutions but you need to know how to integrate all the numbers and in which order. the new version makes this a lot simpler. You should probably at least glance at TiborasaurusRex's Sniper 101 videos too since I made the thing with his table designs and calc form designs.