Transonic flight

[jasent]

Jasent, congrats on those hits. If you have access to Bryan Litz's Applied Ballistics for Long Range Shooting book, Chapter 16: Weapon Employment Zone Analysis contains a great WEZ of the 243Win (see pg 302-306, 310-312) depicting effect of uncertainties (range, wind, rifle/ammo precision, velocity, target size) on hit probability. WEZ allows analysis of which parameter contributes the most to misses at various ranges. Standard Deviation (SD) in muzzle velocity (including velocity measurement discrepancies); range estimation error (a digital number isn't always correct); wind uncertainty (wind reading is THE ART of the system); shooter capability, etc are really critical with obtaining hits at range......even zero distance, and rifle cant become critical. Accuracy and Precision for Long Range Shooting Chapter 8: Leveling Your Sights shows how 3 degrees cant with .243 can induce horizontal error of 16.2" @ 1000yds (0.4" vertical); 41.0" (only -1.1" vertical) @ 1500yds. Human eye only discerns about 3 degrees under best conditions....before introducing optical illusions of tilted visual references, Cant gets misinterpreted as horizontal wind error and one ends up chasing their tail. Install and learn to use a good level.....every shot! Bubble is OK; ceramic ball (Accuracy 1st) is better; electronic (Send It!...down to 0.2deg....Long Range Arms, Idaho Falls, ID) is best.....IMHO. Keep ringin' 'em!!!

Thank you

i do run a level. I do have the book and have read it all along with some of his other books. My es is 3-6 depending on the batch and how well I did at loading. Wind was 12 o'clock with some gusts switching from right to left at 1380 and 1515. First shot miss at 1515 was left 3 min next 4 I held 3 min right.

 

[Pro2A]

WELL DONE!! REALLY tight es. That would be amazing for SD. Your pic looks like you have some great shooting terrain. Vertical wind component could be confounding as well. Interested in how you read the wind over the canyon you appear to be shooting over. Line of sight is probably way over any indicators...not to mention winds up to maximum ordinate of bullet flight above LOS at those ranges. With all the indeterminate variables, it's a miracle we ever hit anything!!! You would probably enjoy attending AB Seminar. In addition to the class info, hearing the evening breakout session leaders and other attendees is worth the price of admission. I was fortunate to attend the 2018 Spring Seminar at Snowbird outside Salt Lake City, UT in early June. Want to attend Gunwerks in Wyoming.

 

[jasent]

Mirage is the easiest way to judge wind it that area. Missed shots even better lol. Thermals are definitely present and some times strong. I do well using trees as indicators but that area burned up 2 years ago

 

[LR3]

My AM .338/505 at 3270 fps is very accurate to 2650 yds but I could not get it to 3100 yd going transonic with Berger 300 gr. Used AB. If I had time I d try to figure out the transonic numbers.

 

[jasent]

My AM .338/505 at 3270 fps is very accurate to 2650 yds but I could not get it to 3100 yd going transonic with Berger 300 gr. Used AB. If I had time I d try to figure out the transonic numbers.

have you tried the custom drag curve? Are you able to see splash?

 

[ar10ar15man]

lead me a little.
i read the current reviews of ab down load and it aint good.
i have his books, and i want a WORKING APP.
???
thanks

When going transonic....about 1325fps down, you will benefit from using Bryan Litz's Applied Ballistics Custom Drag Curves. (G7 BC curves are fine above 1325fps.....if they are accurate. Caution: Many manufacturer BCs are optimistic as they use their best BC for only one velocity point. BC varies over the entire velocity range. Hence, CDCs are the best.) These can be accessed in AB Ballistic solver found in Kestrel 5700 Elite Ballistic; Sig Kilo2400ABS, or one of several AB stand alone solvers (from $29.99 Google Play Store app; $125 AB mobile app; SB Point Mass Solver included with Applied Ballistic for Long Range Shooting book about $50; or AB Solver with complete program suite including WEZ (Weapon Employment Zone analysis about $200, etc.) These also allow specific curve truing at extended range for your specific system and DOPE.

 

[Pro2A]

lead me a little.
i read the current reviews of ab down load and it aint good.
i have his books, and i want a WORKING APP.
???
thanks

You are correct that the $29.99 app has terrible reviews and apparently zero current AB support. However, the programs in the Kestrel, Sig Kilo and the full blown stand alone computer program from AB allow one to access the Custom Drag Curves for specific bullets. The programs are very accurate and are state of the art. Attend the AB Seminar and you get the full program included in the registration cost. That version includes the WEZ and other features not in the Kestrel and Sig devices. Using a BC always diverges from actual nearing transonic region below 1340-1325fps. A BC is only accurate at specific velocity as BC is speed dependent. I use the Terrapin X linked to the Kestrel 5700ABS, and, the full program on a tablet (full WIN 10 version...not mobile...and USB required) to go beyond just the specific ballistics. Don't get the Kilo...redundant program; less accurate/capable that Terrapin X; high potential for using unintended profile; only 4 profiles supported at a time, etc. Pay once; cry once.

 

[jasent]

I use ab app and it's great. Full bullet library and custom drag curves available. I started using it after I started this thread and have been with in a 1/4 moa out past transonic

 

[ar10ar15man]

thanks.

You are correct that the $29.99 app has terrible reviews and apparently zero current AB support. However, the programs in the Kestrel, Sig Kilo and the full blown stand alone computer program from AB allow one to access the Custom Drag Curves for specific bullets. The programs are very accurate and are state of the art. Attend the AB Seminar and you get the full program included in the registration cost. That version includes the WEZ and other features not in the Kestrel and Sig devices. Using a BC always diverges from actual nearing transonic region below 1340-1325fps. A BC is only accurate at specific velocity as BC is speed dependent. I use the Terrapin X linked to the Kestrel 5700ABS, and, the full program on a tablet (full WIN 10 version...not mobile...and USB required) to go beyond just the specific ballistics. Don't get the Kilo...redundant program; less accurate/capable that Terrapin X; high potential for using unintended profile; only 4 profiles supported at a time, etc. Pay once; cry once.

 

[johnlittletree]

Keep in mind that bullet shape is more important than speed when you start to slow down. Some bullets transition better than other's. Just something to keep in mind.