ALWAYS use temp stable powders. Going to any new cartridge the first thing I do is find out what is the best temp stable powder for it. The last thing you need is one more variable trying to hit at distance. Even if the temp unstable powder makes more velocity, it's not doing any good of it varies. Shooting precise at near or far is about eliminated variables.

I agree to try the G7 first, as a general rule. I've had the G-1 work well, though. Thought you said your app doesn't have a G7 as an option, but maybe I was making that up in my head.

Use your calipers and measure center of bore to center of scope I believe

It's on a short action Rem 700, and you are correct, I am limited on length. I don't remember my COAL offhand, but can get it once I get home this afternoon. It is seated pretty deep and I am currently running 63.1gr of the R22.



All it says is Ballistic Coefficient. It doesn't specify G1 or G7. The extended family member that helped me build it, has a rifle very similar to mine and ran R22, so it was just a starting point with me. I've heard it was temp sensitive, so initial load work up was early this spring in cooler weather. I was actually thinking about cooler weather during hunting season while loading, believe it or not, but didn't really think so much about shooting during the summer and pressures getting higher. I guess being a new reloader, I over looked that.

Starting out, I was chasing the nodes of tightest groups at .5 increments, and found the tightest grouping, and then worked around that node to fine tune it. I know all guns and barrels are different, but I was actually only .1gr different than the guy's gun that helped me.

I could have sworn that's what I did Jeff, but i'll double check it. It says 2.00" currently in my app. I'll remeasure tonight.

In a short action, H1000 is about as slow a powder that you can run, and it will still be a compressed load. How compressed, depends on your COAL, and how much room you have. If you played it safe and went with a powder equal to R22, H4831 SC would be a good choice. It will be a less compressed load, and is near identical to burn rate as R22 is.

On your main rilfe screen go to the " drag function " tab and you can change it from G1 to G7

Well, I have the cheap version of strelok apparently. I remembered I paid for it, but apparently I didn't buy the pro version. Mine doesn't have the drag function.

Found my old thread about when I finished the rifle.

180gr. Berger Hunting VLD seated to mag length 2.950"

Try running your numbers on another calculator, there are some pretty good ones online and see if they agree with your istrelok. Hornady has a free one and go to advanced version to put in all the atmospheric and G7 BC for your loads.

Base version is free on android 4.99 on iTunes, the Pro version is 11 or 12 bucks on both platforms.

I have played with the base version for a couple of years and couple of changes I have made and found useful are:

Use an avg G1 over the velocity range for my input and it has helped particularly at 400+ yards.

Set the 0 weather to actual conditions when you zeroed. On android version 0 is set to current conditions which in your case cool to hot would throw the data off. Once you do this make sure you adjust to current shooting conditions or else you are shooting using last sessions weather data. Based on your screen shot looks like you have this one covered.

I adjusted my Temp Sensitivity Factor to .5 after gathering chrono data from two sessions one at 60 degrees and another at 75 degrees. I see you have .9 as input is that based on data?

Final tune was to adjust muzzle velocity until the elevation output matched the actual result at 600 yards.

This has given me very good results across weather conditions out to 800yrds.

I honestly couldn't tell you how I got temp sensitivity.

Where you say final tune, that's what I did at 750 yards. I tuned my strelok to match my actual dope for 750 yards (3.6 mils) and that's the only place the two trajectories match (except at 100 - 0 mils)

Try .5 as temp and avg your g1 and see how the numbers come out keeping all else same.

That's getting a lot closer. I'm still tweaking numbers to get it closer

Glad it is tightening up.

Yup

You should see guys with a $600 Kestrel w/ Applied Ballistics get mad when things don't line up!

if you have the opportunity try doing your scope height calculation like this...

http://www.texasprc.club/measuring-your-scope-height/

Interesting read...thanks

Never!!!

Interesting read Dave. Thanks.

I remeasured my scope height last night and it was a bit off... this time I used my calipers and measured bolt diameter, scope tube diameter, and the distance from the top of the bolt to bottom of tube.

Bolt diameter / 2
Tube diameter / 2
distance from top of bolt to bottom of tube.

I added all together and got 2.146. I guess my eyeballing a tape measure (2") was a bit off... I changed this number and it's still getting closer. I appreciate the help fellas. I'm going to continue messing with numbers and see what I can come up with.