180 hybrids - new boxes 1:8 twist vs the older boxes with 1:9
- Thread starter bsumoba
- Start date
No changes. Most are still running the 9 tw. The recommended twist on the boxes changed some time ago when Litz recalculated the stability factors. When that happened many switched to the 8,8.25 and 8.5 twist barrels and then realized the 9tw shot the same or better.
The bullets did not change, just the print on the box with a “recommendation”. I continued with a 9tw and I am at 150-220 ft above sea level and my temps have ranged from 45° up to 115° over a year. I also had success with Sierra 183’s in a 9tw contrary to what they also recommend. I have also asked a few of the folks that usually place high on the podium and the 9tw is still preferred and they tell me it just works and seems more accurate.
Ultimately, you need to let your rifle tell you what it likes and you need to test for yourself. The more people follow these recommendations, just makes the 9tw barrels more readily available.
*I also heard H4350 is the worst powder ever and your barrel will wear out prematurely! Please stop using it because I would like to get some for myself and arrive at my own conclusions*
Ultimately, you need to let your rifle tell you what it likes and you need to test for yourself. The more people follow these recommendations, just makes the 9tw barrels more readily available.
*I also heard H4350 is the worst powder ever and your barrel will wear out prematurely! Please stop using it because I would like to get some for myself and arrive at my own conclusions*
GT Accuracy
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Be careful with the new ones. I have heard grumblings that the new lots are up to as much as .030 shorter base to ogive. More than one tested lot using sorteez has proven that out
Greg,
Do not adjust the bullet seating stem and seat a bullet from the "new" lot and check the cartridge base to ogive ( CBTO) it should be the same as the old lot or very ,very close. I did a test on 3 lots of our 6.5 130gr VLD Target bullets that were about two years each apart in production.
First lot was 0.6200 base to ogive
Second lot was 0.6750 base to ogive
Third lot was 0.6525 base to ogive.
Using a Wilson Microtop seating die . Used LOT 1 to set up the die to give me a CBTO of 2.070. Leaving the setting alone I then seated lots 1 and 3.
Lot 2 CBTO = 2.0705
LOT 3 CBTO = 2.0695
Did load development with Lot 2 then loaded samples of other two lots with the exact same accuracy load and bullet seating depth.
Using 10 shot groups.
Lot 1 AVG FPS = 2630 SD =11
Lot 2 AVG FPS = 2635 SD = 4.3
Lot 3 AVG FPS = 2649 SD = 11.1
So I need to test this summer lots 2 and 3 to see what needs to be done to get the SD DOWN. Load or bullet seating depth adjustment? There will be a series of articles in the BERGER BLOG on this.
Last edited:
Jay Christopherson
Not An Admin
as long as they (continue to) print small on paper, they can change them however they like... 
GT Accuracy
Site $$ Sponsor
Great to hear - I was just relaying what I saw when a few people measured some of the new lots at Berger.
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