So I just recently performed a powder sensitivity test. The goal was to build my MV TEMP TABLE in my Kestrel 5700. But I figured since I had the chance, I would test 2 powders and get some results.
Powders tested were LEVEREVOLUTION and Gods powder, VARGET. Results were surprising.
These loads were tested in my gun. Use at your own risk. I’m not a scientist. I’m a redneck long range shooter. This post is just information.
Load 1 (COMP):
105 gr Hornady BTHP
HORNADY brass
CCI-41 primer
29.7gr LVR
CBTO: 1.700”
Load 2 (Varmint):
87 gr Hornady VMAX
Resized Hornady 6.5G brass
CCI-41 primer
29.7 gr VARGET
COAL: 2.140”
Test equipment was a magneto V3 chrony, my 20” PROOF 6ARC, and a laser thermometer.
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I had 4 different situations I wanted to test. Room temp, cold, frozen, hot. Room temp was ammo sitting in my gun room. 65°. Cold was ammo sitting in the fridge for 12 hrs. 39.5°. Frozen was ammo sitting in my freezer for 12 hrs. 15°. Then hot was ammo sitting in a blanket of hot hands for 30 mins. 90-100°.
Outside temperature was 81° / SP 29.4 / RH 57%
Barrel was fired 3-4x at a moderate rate, (think target engagement like 2-3 sec between) and barrel maintained a 80-85° temp just in front of the barrel nut (outside barrel reading).
I Started with the Varmint load first and alternated between the 2. I would load 3-4 of each round in a mag, run around the back of the house, and shoot over a chrony. Time between removing from environment and shooting was around 45-60 secs. I repeated these steps with room, cold, frozen, and hot in that order. The results certainly surprised me.
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The numbers from my test showed that LVR performed better than VARGET. Wwwhhhaaatttt?????
Now I get it, the best case scenario would be 10 rounds from each test. Also shooting in ambient temperatures equal to ammo temperatures. But that’s expensive and even though the temps swing pretty drastic here in the Midsouth in the spring time, the environment was unobtainable this evening. The intent for me in this test was to merely grab my MV, and to build the temp table. Then true BC at what ever environmentals that day and let the kestrel do the rest.
The columns you see for MV are High, Low, AVG. Some shots were 3, some 4. One was only x2 as I had feeding issues. (Varmint loads were for a different rifle)
LVR swung from lowest @ 2708 to Highest @ 2782. Swing of 74°.
VGT swung from lowest @ 2914 to highest @ 3033. Swing of 119°.
Now I’m not getting totally bent out of shape over the temp swing. The most intriguing part is that fact that from 15° to about 75° (75° based off range session MV / TRUEING the week prior), the MV in the COMP load was within 30FPS. Consistently. That speed node for LVR is wide. That’s incredible.
There were some issues as the MV creeped up. I did have a blown primer in the Hot COMP load. I’m not convinced that this was a MAJOR pressure issue as this brass is my “TEST” brass. So she’s been ran hard (maybe 6 firings???). But nonetheless, still to hot. I shouldn’t be getting 2780 in a 20” gasser 6arc. That’s pushing it. The flatten primer has been consistent in loads down to 2650, so not concerned there. Ejector swipes and extractor burrs are my main indicators in this rifle. Those were present.
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So take away? 29.7 maybe a little spicy for hot ass summer days/desert/rounds exposed to sun. I personally would back my summer load off to about 29.4-29.5. Then in colder weather, load back up to 29.7. The SD and accuracy are so good at that node that it’s hard to shy away from it. (I found that with LVR, the accuracy node with 105 BTHP Was from 29.6-30.5grs. The increase of velocity was less than 2-3 FPS per grain. So running them a little light in the loafers was no real detriment to performance. Even tough 29.7gr is listed gas gun max, my guess is Hornady saw this speed node as well and directed everyone towards it.).
LVR performed exceptionally well for temperature variations.
Going forward, I will take my temp table I built and true via BC adjustments and see if the data holds. The #1 problem IMHO in long range shooting (when it comes to actual gear/equipment holding you back, not skill level) is bad data. Take the time to ensure at least your zero and drop data are dead nuts. Scope is leveled properly. Those are purely equipment functions. The rest is where a skilled shooter can increase performance.
It would be very efficient if a simple MV test like this can build a useable MV TEMP table that holds true to your load across many environments.
My next question for
@Kestrel Ballistics is what are your thoughts on a humidity table?
Again, this is purely hillbilly science and don’t use this method or these loads without proper testing. But hopefully this information may help somebody.