I would love to see this range of results even if it's by PM if you don't mind sharing.
Last winter I made arrangements to use a range that would allow us to use steel targets the facility had that went out to 2480 yards. Rare in Wisconsin, I was lucky.
I had just finished up the load development on my friends 375 FU in which is a 375 Snipetac that had its shoulder set back 150 thou in order to #1 get rid of wasted case capacity that was not being filled with RL33 or RL50 powder. #2 being this rifle also had a Mag used at times we wanted to be able to use the higher BC bullets and still have them fit in the Mag.
The results of this was less powder could be used with a gain in speed compared to the standard 375 Snipetac which made it more efficient. But we still are close on the rounds fitting the Mag with the 361 grain Flat line solid - they fit but are close.
During my load development using the RL50 and running at 50 thou off the lands I found the sweet spot I was looking for at 100 yards doing a grid test checking speed and impact points. I wanted to shoot at say 500 to 800 yards in my back yard but that was not happing with work issues prior to heading to the facility.
My goal at the facility was to
#1 see how accurate the 361s were at distance.
#2 see what happens with bullet stability as it travels through transonic & subsonic
#3 see how the estimated BC on the bullet printed at distance and adjust if needed
#4 leave there with confidence in grouping and a very good BC number that works in the ballistic program.
It was dang cold negative - 22 degrees F. Yielding a Density Altitude of a negative - 4218 DA - very thick air.
First off they wanted me to confirm I could hit at a 1000 before moving to the 2480 yard plate.
I set up the Lab Radar and fired a cold bore 1st round shot at the plate the flasher went off on the target confirming a hit, so I held the same and fired a follow up.
My cold bore shot and the follow up were 3 fps different which was good.
They came back from inspecting the target and said my group was 6" high above the painted dot on the plate and both impacts were 2" apart. So I was good to move to another range for the 2480.
So prior to sending any rounds at 2480 yards I knew my speeds were very consistent at the 1000 and at home. So I went into my program and started to tweak the BC number higher a little until it had me dialing 6" of less correction.
Note during the testing this day I kept the ammo temp at 78 degrees and only grabbed the test rounds needed before getting behind the rifle in order to keep some consistency in the test.
At the 2480 we had slight 5 mph winds on and off at either 6:00 behind us or at 4:00 at our side you could see the shift in the wind by watching the mirage thru the scope and we shot 3 round groups in the same wind conditions to see if the bullets were grouping respectable as well if there was any instability starting to show because of the bullet slowing down enough in the thick air to see what effects were happening towards the end in transonic flight.
Group sizes on the plate or in the snow close to the plate were very respectable at that distance out the the 12 rounds fired there 4 groups of 3 shots group sized very from 9" to 15" when waiting to take advantage of the winds and in a relaxed day of shooting, not under pressure.
The groups shot with the 3-4:00 wind which normal should be impacting higher versus a 6:00 wind were actually impacting 16" lower, we concluded that the tail wind which a lot of times pushes down some actually pushed the bullet some and the bullet maintained speed longer.
The speeds still were in a nice zone
The BC number I tweaked in the program held true at distance
The bullet grouped very well at both distances
when shooting at the 2480 it was great to see the bullet went through transonic and into subsonic very well and didn't start going in different directions.
The best part is we were able to get into that transonic - subsonic zone and see what the bullet was doing without having the wind, human error all the things that would distort testing results when shooting in normal temps where the bullet would be going in those zones at 3500 yards.
We used the Lab Radar with a battery charge pack and with the rifle located directly under the Lab Radar eliminating any disturbances from gasses and smoke.
The rifle a McCree chassis, Stiller action, Vortex Razor Gen II and a Bartlien barrel showed zero issues or strange things happening while sitting out in the sub zero temp during the day while there. The only thing that was managed as far as keeping warm was the ammo in order to get a good test.
I would of PMed all this but a few asked to see this here
osoh
