G1 or G7? Confused!!!

[bubbapug1]

I have a question. I am sure it has been asked, but I couldn't find it in search

I was building some wind charts for 223 (80 grain noslers - 2650 fps - 20" WOA upper) and ran the program with a g7 model. Last year I ran the same calcs using a G1 model, and even shot a match with the data which proved accurate for windage.

The difference between the G1 model and G7 at 600 yards in 15 MPH is almost a factor of two.

G1 model - 15 mph cross wind 600 yards = 58.91"
G7 model - 15 mpg cross wind 600 yards = 25.22"

Which should I use? I have you not back checked the data and the matches are Saturday (iron sights) and Sunday (scopes)

I am not good enough of a shooter with irons to know for sure, although I am sure to note if I am off by 25" as that will put me off the frame! I am sure after Sunday I will know, but I'd rather know Friday and keep my scores higher.

I could swear I dialed in 58 inches on a 15 mph crosswind day and shot a 184, which for me is good.

I'm confused as the G7 models worked great at 1000 yards with my Sierra 284 175 grain bullets...perfectly in fact.

[nubrun]

Here is a great write-up from Bryan Litz. http://www.calguns.net/calgunforum/s...d.php?t=283567

I would recommend the G7 model.

[GeoffLinder]

Yes, G7, or G5 if it is an available option. G1 is only for flat base projectiles. Boat tails like the SMK's need this correction applied to the Mfgrs stated BC which is almost always G1. I use G5 corrections for my SMK's in several calibers and it is spot on, G7 may be best for the 80gr, but G5 will be right there too. My calculator supports G5 and G7 corrections.