More Testing - Howa 6 ARC - 105 Berger Hybrids

270quest

WKR
Joined
Jan 31, 2017
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831
Location
Boise, Idaho
Got out today and got 35 more rounds thru the little 6 ARC. I had ordered up 200 Berger Hybrids 105's. Multiple recommendations on these to both shoot well and kill handily.

Worked with H4895 again at 27.0 and 27.5 - both at a COAL of 2.380". Gun really seems to like these bullets and once again, seems to show promise of a fast barrel. 27.0 averaged 2750 FPS, 27.5 got me up to 2800. Groups opened up at 27.5 so I think 27.0 is my load - just may tweak seating depth a bit to see what that does. 27.0 load put 10 rounds inside a circle the diameter of a 50 cent piece and just a tad larger than a quarter at 100 yards. I can for sure live with that cone. Around an 1" for 10 shots.

I also shot 2 groups with Varget (27.0 and 27.5) - nothing special in the accuracy side and velocity was about 100-150 FPS less than the h4895.

That puts me at 65 rounds down the tube. Will continue shooting the H4895 loads and try to get the barrel settled in to see if it speeds up much or not. I also don't have the fanciest of chronographs so next time Out I will probably shoot the 27.0 load out to 4/500 yard gongs and see if the velocity is true. Also will give me a chance to wring out the SWFA and test the tracking and return to zero. (not too worried there)

Assuming velocity is good, a 105 hybrid at 2750 FPS from a 20" suppressed barrel with a powder that isn't extreme on the temp sensitivity is a 100% win and going to make one heck of a hunting rifle/load.





 
Looks like you found your load. Make up 100 and break her in. Looks like you're one of the lucky ones. If I knew I could get one like that, I'd order a barreled action tonight but since I really like pushing my luck, I think I'm going to build a 14.5" upper to run with a thermal.
 
I was 2.380 - touch the lands with that bullet at around 2.390. Will load some at 2.370 to see if the standard of .020 off is the magic ticket

Don't be afraid to make more macro jumps. I'd figure out where you are getting close to compressing powder and start from there. Granted it's likely not that far. If you have 100thou of room, load 5 at 25thou increments. From there go more micro on either side of your best example. I bet you could have it dialed in by 100 total rounds.

I've been humbled a few times jumping bullets much further than you would think and really tightening the group up.

Completely speculation but I feel like there might be something to the case fill percentage at play or it could be, and likely is much more intricate than that.
 
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