I ve completed my first round of sniper 101 amd have built my first set of charts. I ve rewatched several episodes and feel like I have a firm grasp on computing a firing solution. Where I live at in south dakota i have only 650 yrds at my convience and with an altitude of 1250. When i travel to go back home to Wyoming in a couple months i am going to get to stretch my legs on the family ranch. The altidude there will be about 6000 feet. Will just my barrometric pressure corrections fix this difference? I ll have my magnetospeed along and collect data for that location but i want to showup with as much info as i can. Could you please share with me your dope, data and corrections and experiences with such changes. Thank you
merwin907
6 days ago
Oh lord why didn't I listen! Why did the Steiner have to be out of stock everywhere I looked! I ended up getting a 5-20x50mm Razor HD for $1899.99, what a great deal. Put in on my beautiful newly rebuilt savage 110. XLR chassis, MPA single piece rings, Atlas BT-35 bipod, a smoking hot 29 inch stainless heavy palma barrel, and a camo Cerakote on the whole thing. I get it all together and I am ready to shoot laser beams with this thing. Nope, POI shifts as much as 10 MOA JUST SITTING IN THE CASE. I cant get it zeroed, cant index a FS, cant do anything because of a $1900 POS. I saved my pennies for so long to have a rifle that would make heads turn. I was starting to really reach out there with the range- pushing 1200, 1300 yards and making first round hits- so I wanted to treat myself to something nice after practicing twice a week for almost two years straight. I had my eye on the Steiner T5XI, and they were on sale for like 1300 bucks, but everyone else and their sister saw it too and bought them up quick. I settled... I am sending the scope to vortex today, hopefully I will get one back that works. I was in denial- Couldn't believe the stories were true. I tried everything to correct the problem. Bedded the action into the chassis, unmounted and remounted the optic like ten times. messed with torque and turret caps. Its a crying shame that at 400 yards, I can't hit the target because the scope put my projectile three feet to the right. If they send me a new scope as some attempt to rectify the issue, I am going to the local fudd forums and I am going to sell it for $1500 brand new in the box, and I am going to put my SWFA back on until I can afford something from IOR. at least with SWFA I know damn well I will make a hit whether its rain or shine- I have three of them and they are all reliable. like, go-to-war level reliable. Its sad that a guy can start really feeling confident about LR, and then have a piece of equipment bring him down. I took this scope to my first competitive shoot ever in my life and I didn't hit a single target- put me in last place... I felt like a moron lugging this 28 pound beast of a rifle around like I was some kind of badass and then have my equipment fail on me- totally making me look like an idiot. further more, half of the guys out there had vortex scopes that somehow worked. makes me sick. I am glad you all are here to listen to my angst. sure, I could afford to be a little more humble about the whole thing- and I would be if this wasn't a $1900 mistake. Had Athlon been known to me before hand, I would have went with that.
If you are measuring absolute barometric pressure, you can use that find your correction value. The absolute barometric pressure for 6000' should be around 24.00 inHg. If the pressure you are seeing is more in the 29-31 range, you are looking at a corrected "station pressure" which won't account for the altitude difference.
How you apply this will depend on how the charts are set up. If you follow Rex's videos from a few years back he will show you that you need to create a chart for each air density altitude you plan to operate in. So if you're at sea level you would want a chart for about 30.00 inHg, and perhaps one for each 1" in mercury change, all the way up to 24 inHg.
When you get to your firing position, read the absolute pressure on your device (make sure it it calibrated to display absolute pressure, not corrected pressure) then use the chart that is closest to that pressure, or interpolate the values between the charts.
If you haven't yet downloaded and played with the ballisticxlr's spreadsheets, you need to. Just spending a day studying these can teach you a lot on how to apply corrections. Of course you need to make sure all of your inputs are correct.
Hope that helps!
As mentioned above make sure that all data is correct. Also if shooting at an angle through another pressure change account for this also Rex has you covered. Watch his episode on his calc form this will help you build the charts for primary and secondary ballistic data. Fun stuff
Yes very fun! And challenging! Thanks for the input! Mecca Streisand had to bail me out some incorrect data entries already!