G7/Shooter/Exbal conflicts

[D.Camilleri]

I just got in a new rail for my scope. I am removing the LH EGW HD rail 20 moa and replacing it with a 0 moa rail.

I shot the gun this morning with the new rail, my theory is that the elevation turret was down too close to the bottom with the 20 moa base and that going to a 0 moa rail would help. Two shots and I had it zeroed at 100. Shot at 200, 2.0 inches low, 300, 8.75 inches low. Temp was 65 degrees. I went back out at lunch time and shot at 690. I dialed 15 moa, one shot hit 3 inches high and the other hit 12 inches high, temp was 85 degrees. I ran the trajectory numbers and came up with 2744 for a corrected velocity, but that still doesn't jive with my drops at 200 and 300?????

Yesterday there were too many people at the range for my liking, so I just did some experimenting with a new muzzle brake I built, 3- .500 ports on each side, 1 inch diameter, definately works better than my radial brake, but also weighs about 4 oz more.

While I was on the bench yesterday morning, I tracked my scope top to bottom on a 4x8 piece of plywood. It took 43 minutes of adjustment to go from the top to the bottom of the plywood. Based on 1.047 inches = 1 moa, my 43 minutes = 48 inches, but it should only be 45 inches. How do I change that number in the program?

 

[Canadian Bushman]

I dont know about your other programs but shooter has an elevation correction factor that you can adjust in settings.

 

[D.Camilleri]

I entered in the elevation adjustment and went out and shot again. Hit one minute high. Made a velocity correction up to 2900 and shot again, getting closer. Dialed the scope back to zero and drilled a perfect bullseye. I also made a change to allow shooter to calculate air density. With this it is showing calculated altitude at 6025 ft based on the weather data it is gathering. Slowly, I am gaining on this problem and getting closer to having it figured out. Changing my base from a 20 moa back to a 0 moa has also made a difference. I am now dialing 13 moa at 690 yards and I am in the money. This is compared to dialing 15 moa before. My scope seems to be tracking better now that the turret is off the bottom of travel. Is it common for a Sightron S-III to be off 6% in the elevation turret travel?

 

[eshorebwhntr]

I entered in the elevation adjustment and went out and shot again. Hit one minute high. Made a velocity correction up to 2900 and shot again, getting closer. Dialed the scope back to zero and drilled a perfect bullseye. I also made a change to allow shooter to calculate air density. With this it is showing calculated altitude at 6025 ft based on the weather data it is gathering. Slowly, I am gaining on this problem and getting closer to having it figured out. Changing my base from a 20 moa back to a 0 moa has also made a difference. I am now dialing 13 moa at 690 yards and I am in the money. This is compared to dialing 15 moa before. My scope seems to be tracking better now that the turret is off the bottom of travel. Is it common for a Sightron S-III to be off 6% in the elevation turret travel?

Definitely possible for any scope, no matter make/model/price range to be slightly off. To check it, put up a large paper target at 100. Shoot a group at 0. Dial up something extreme, the more the better, but keep it on the paper. Usually 20-30 moa is good. Measure how far it tracks with a tape measure as accurately as you possibly can. From these measurement you can find out what your true click value is and correct for it in Shooter under the setup option for each particular gun.

Example: @100 yards, you dial 30 moa. You measure that the impact from center to center was 35 inches.

30 moa @ 100 yards = 30moa * (1.047in/1moa) = 31.41 inches

Acutal movement = 35 inches

% Deviation = (35-31.41)/31.41 = .1142 = ans*100 = 11.42% off

In shooter the correction factor default is 1.0. For the example above the correction factor would be updated to 1.1142.

As for the other problems you are having between Shooter/G7/Exbal. I've never used Exbal so I can't help much there. I've used Shooter and G7 a fair bit and like others I have drops consistent within 0.1 moa over a long range. You might want to check how you are entering the pressure in each setup and how each setup is using your entry.

On shooter, if available, I typically use the information that it pulls down from the weather station and GPS. If you are entering this manually make sure you understand what is going on in each program. In shooter, you can do 2 options. If you are running a Kestrel at your location you can pull the pressure reading off of that. Just make sure to check the box for "Pressure is Absolute" if you do that.

The other way to do things is to use the relative pressure, which floats from 29.7 for ****** weather up to 30.1 for really nice weather, in conjunction with an accurate altitude entry that shooter will then use to correct the pressure (based off of standard altitude vs air density tables). For instance, where you are in Worland, wy is probably about 5000ft. So the BP should be around 24.5 (that's what I used in Rock Springs when I use to do air flow calcs at the power plant anyway). Right now the internet says the BP in Worland is 30.09. So if you were running shooter right now, you would enter in the elevation of 5000 and the pressure as 30.09, and don't check the box for absolute pressure. The kestrel way is best, the other way will get you pretty **** close in my experience.

Like someone else mentioned. Check that the powder stability parameters aren't wrong. That could be throwing things too.

When I've input all parameters correctly into shooter I've had really good luck with it. I hope this helps get you something that will work.

Good luck.

 

[D.Camilleri]

Thanks for the reply. I have to re verify my tall test on my scope. I made a bad assumption the other day that I was at 100 yards, when in fact I was at 102-104 because of the number of people at the range, I was having to aim across half a dozen benches to line up with a clean piece of plywood. Test was not accurate.

I am having a little better luck with shooter however. I am letting it pull the information from the local weather station. I went out the other afternoon after it rained most of the morning. The humidity was very high for Worland at around 44%. Shooter called for 13.9 minutes at 690 yards. I dialed 14 and took two shots. Shots were two inches apart and 5 inches low. I adjusted my velocity back down to 2730 which actually matches my chronograph and now shooter calls for 14.2 moa. Pretty close. My scope is working better now that I switched to a zero minute rail. It got my elevation turret off of the bottom. When I plug my data into G-7 ballistic table, it is very close with shooter. One thing I still can't figure out, with a dead on 100 yard zero, my drop at 200 is 2.0 inches and my drop at 300 is 8.75 inches, this doesn't match any of the drop charts. 8.5 moa puts me dead on at 500 and that drop matches the 2730 velocity in shooter and G-7. None of this works with Exbal. In order for exbal to work at 690, I have to input 2830 as velocity with all other parameters the same. At this point I am sticking with shooter, and thinking about getting a kestrel.

 

[eshorebwhntr]

No Problem. The pressure stuff is commonly misunderstood from what I've seen

I saw that you said your drop was 2 & 8.75 inches, don't know if you meant moa or not.

Hope you get it figured out and have good luck with it.

If you ever want to print out a chart for the side of your gun in Microsoft Excel pm with your email and I'll send you a template I made a while back for organizing/sizing/formatting/etc the excel file that you can generate from Shooter. I also made a tutorial for it that explains where & what to copy/paste.

 

[D.Camilleri]

Thanks, when I get back from fishing in Canada I will shoot you a pm.