So here's my question I use isnipe and i find it works great. I use Bryan Litz BC and chrony my loads and find that it gets me on paper way out there. I have also plugged in the same data to the swarovski optic calculator and am still blown away with how close it matches up with the brh reticle. What I'd like to know is - does any one know how I could find out how my load would shoot if I dialed it in at say sea level with known temperature and pressure and then went up say 6000 feet with known temp and pressure again and made some shots there? Or even just how much my zero would change and then I could make 2 cheat sheets for the different conditions without shooting to re zero at that altitude. I live by the water but go sheep hunting up in the mountains. Thanks .284

As long as it's a solid program and your inputs are correct, it should spit out correct data. Not likely however to get great results at 6000ft if you enter 0ft for your altitude.

I think it would depend on what your zero is as to how much it would change. Plugging in the desired elevation should get you the desired results. I use the same program on my IPhone. The air at 6000 feet will be thinner and result in less drag. If your zero is 100 or 200 yards, I don't think it would be much. But down range you will definitely see significant changes.

I think you might be on the right track there by using a 100 yard zero as I would imagine the closer distance would vary the zero the least with the altitude change. We know there's going to be less drag/drop with the less dense air but all the ballistics programs that I have used assume that you have zeroed your scope at the altitude that you are plugging in and have no way to leave your zero altitude at sea level and your drop solution data for say 6000 feet based on a sea level zero. You guys see where I'm trying to go with this? Somebody must have travelled this road already.

Most of these good programs will give you great data. If you make your 2 drop charts for sea level and for 6000 feet you should be fine out to the 600 to 700 yard ranges. My recommendation for you is to be an Ethical hunter/shooter and check your zero after traveling like everyone should anyway. When you reach your elevation or hunting destination... shoot the rifle. If your new zero is a couple clicks lower, it will take care of your chart and you now have the confidence in it. Just mark on chart to know that the sea level and 6000 foot altitude is say 2 clicks or .5 MOA difference. here is a great article for you to read.... Barometric Pressure and Ballistic Software