A lot of tech talk but interesting

Jeff Heeg osoh

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Wisconsin
Just one of those wow factor days? Yes I copied this off of a Face Book forum, but I thought maybe some here would enjoy this read.

Question came up about seeing bullets splash in the snow during some testing.
—. — — — — —
If I had to guess there was 8 to 10" maybe more in the target location.
We started out with checking everything at a 1000 yard target
the temp was -22 below zero
we had a negative DA of -4419.
44 Lat
60 Az
I fired a cold bore round and a follow up shot - this printed a 1" group and put a smile on everyones face. Honestly I was really jacked after doing the load development on Ed's 375 FU with a new powder and this was the first real test at distance.

Onto 2458 after the two shots at 1000
The DA was now at a Negative -4000
Lat was still at 44
Az now was 265
The 375 was leaving good skiff and puck marks in the snow at the 2458 yard target area. The target was 24" tall and I think 48" wide. We had a wind running from 3 to 7 mph and coming from our 3 to 5:00. The DA when shooting at the 2458 yard target was a negative -4000. The bullets at the target were at the point of transitioning from transonic and soon to be subsonic they were at Mach 0.90, we paid close attention to the mirage and then started to send the rounds in a volley of two shots when the mirage would shift to a boil stage. I believe Adam was able to see all the impacts, I also believe out of the thirteen rounds fired if it wasn't a impact on the 24" steel they were right below the plate or just over the top edge other then the first volley that I ended up adding a few 10ths of a Mil due to landing in front of the target Adam Kodra is more then welcome to chime in, I believe when we did the two shot volleys our impacts were in a ridiculous 8" groups. I was happy with the results and was able to fine tune the BC of the bullets in my program and feel very humbled with the rifles performance. I really can't complain with the results or the bullets it was impressive and I thank Adam for his great support and help making this test happen in what I believe were perfect conditions pushing the limits on a bullet.
375 Faber Ultra - 3047 fps with Warner Flat Line 361 gr bullet.
9 bullets used prior during load development to find node and 15 shot at distance in this report.

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It was amazing to see the groups that Jeff Heeg was printing. It was also great to have a like minded shooter interested in the science behind shooting and who understood the importance of every round fired. Some rounds were difficult to spot. Some would enter the snow leaving a small hole the size of a permanent marker, while others must have hit ice and caused quite the eruption of dirt and snow! That being said many of Jeff's groups we found were sub 10". A couple of bests were in the 4" area 😮.

We've all been at this a long time, but this has been the first time that I personally have witnessed the effects of a boil (in our case wind from 6 to noon) verses cross winds. During a boil (in the spotter) it would cause Jeff's rounds to hit 1/10-2/10's LOW. During a cross wind he would regain his 1/10-2/10's elevation. This was consistent as we saw the effects about three times apiece. At the end we had our "ah-ha" moment and were able to figure out Jeff's hold for elevation based on a boil in the spotter or a crosswind in the spotter. We figured this out in the last three rounds of the day, resulting in impacts and what I think is the smallest groups of the day as well.

Interesting enough, Jeff also was able to consistently print 2-4 inch vertical deviations as long as the wind maintained constant direction. This, I assume, can be attributed to precise Bullets and even more precise handloading.

It was a blast and I can't wait to do it again! Being able to have the bullet go into the trans/sub sonic zone, in my opinion, is so critical to building a proper drag curve! Shooting in such low negative DA's afforded us this ability at a much shorter range then if we had positive DA's!


Always a great time when you can pull some trigger

Iamosoh
JH
 
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