Berger to introduce 7mm 195 gr EOL Hybrid Hunting Bullet

Could be a dangerous hunting combo for guys like me that don't care to step up to the bigger magnums. 3000 fps with this bullet is ballisticly impressive for a 1000 to 1200 yd hunting round. Sign me up! Sounds like a rebarrel for my sendero!
 
how many groves are you fellas going to run for the fast twist barrels needed for this bullet?
I heard 3 groves in a barrel is hard on the jackets.... I was thinking about a 7 twist to stabilize it at longer ranges and wanted to make sure I had a good amount of groves so my barrel will last as a shooter as long as the lands do..... I was thinking a 5r or even a six grove custom cut...
 
trappers son said:
how many groves are you fellas going to run for the fast twist barrels needed for this bullet?
I heard 3 groves in a barrel is hard on the jackets.... I was thinking about a 7 twist to stabilize it at longer ranges and wanted to make sure I had a good amount of groves so my barrel will last as a shooter as long as the lands do..... I was thinking a 5r or even a six grove custom cut...
Click to expand...

We are on the same page. But I will stay with an 8 twist. I think a Hart 6 grove would be hard to beat here.

Jeff
 
yep, 8 twist would be ideal, I would like to push these to a mile just for fun and I am not sure if it would stay stable that far if I don't spin the **** out of it :)
 
Broz said:
We are on the same page. But I will stay with an 8 twist. I think a Hart 6 grove would be hard to beat here.

Jeff
Click to expand...
I'm on a Shilen (select match) 6 groove 8" twist here in 7mm stw. I was looking at 5r, gain twist, and ratchet rifling, but the wait was too long and the benefit/ cost ratio didn't add up. Twice the price for little, if any benefit.
As to barrel life, I already have 100 rounds on the barrel, and I am seeing zero wear. I've got enough straight shank on this barrel to whack an inch off, re-chamber, and run her another 1,000 rounds or more. I will see at least 2,000 rounds out of this 7mm stw barrel with sensible hand-loads.
I'm hoping the rifle likes the 195, as I wouldn't have bothered with the 8" twist without heavy pills on the menu. To date, the best groups are with 140 nosler bt's and rl25 though.
 
I just realized that there will be less force acting on the front of the bullet at lower velocities but I am not sure if bullet rpm decreases as well or if it stays constant at longer ranges.... I am not worried about transonic speeds (dynamic stability) cus I know this bullets profile will make it tumble like crazy after it hits that zone but I was wondering if anyone knew if the gyroscopic stability would stay intact at long distances..... If the bullets rpm stays constant the bullet theoretically should not decrease in gyroscopic stability but if the rpm decreases with extended range the projectile has a probability of having lower gyroscopic stability if the affects of the lower rpm's influences the bullets stability more than the decrease in aerodynamic torque acting on the front of the bullet due to lower velocities.... Anyone have an idea? Bryan? haha I'm not a rocket scientist so it would be good to know.....
I would rather have a slower twist rate if I can get away with it. I am shooting a 7mm weatherby rouge that has a case capacity of 91 grains up to the top so I was looking for 2900 ft/sec in a 28 inch barrel.
 
trappers son said:
I just realized that there will be less force acting on the front of the bullet at lower velocities but I am not sure if bullet rpm decreases as well or if it stays constant at longer ranges.... I am not worried about transonic speeds (dynamic stability) cus I know this bullets profile will make it tumble like crazy after it hits that zone but I was wondering if anyone knew if the gyroscopic stability would stay intact at long distances..... If the bullets rpm stays constant the bullet theoretically should not decrease in gyroscopic stability but if the rpm decreases with extended range the projectile has a probability of having lower gyroscopic stability if the affects of the lower rpm's influences the bullets stability more than the decrease in aerodynamic torque acting on the front of the bullet due to lower velocities.... Anyone have an idea? Bryan? haha I'm not a rocket scientist so it would be good to know.....
I would rather have a slower twist rate if I can get away with it. I am shooting a 7mm weatherby rouge that has a case capacity of 91 grains up to the top so I was looking for 2900 ft/sec in a 28 inch barrel.
Click to expand...
trappers son,
Go to our website and use the twist rate calculator under the BALLISTICS tab on our home page.
Some dimensions you will need are :
G1 BC =.755 ( 1500-3000 fps)
G7 BC = .387 ( use this , not G1)
BULLET OAL = 1.648
Be sure to enter the ALTITUDE ! This can be found on the NOAA website. Use the zip code to find.
 
Thanks Barefoot, I understand that portion. I just needed to know if there is a decay of bullet rpm at extended range. I don't think that the spin of the bullet is constant but I just wanted to have it verified by someone who understood the physics of bullet flight. I know the decreased bullet velocity decreases aerodynamic torque but I wanted to know if this stays true for the bullet during its entire path in supersonic flight. I appreciate the response though.
I just want to make sure I have the right amount of twist for the bullet to stabilize at extreme distances.
 
trappers son said:
Thanks Barefoot, I understand that portion. I just needed to know if there is a decay of bullet rpm at extended range. I don't think that the spin of the bullet is constant but I just wanted to have it verified by someone who understood the physics of bullet flight. I know the decreased bullet velocity decreases aerodynamic torque but I wanted to know if this stays true for the bullet during its entire path in supersonic flight. I appreciate the response though.
I just want to make sure I have the right amount of twist for the bullet to stabilize at extreme distances.
Click to expand...
trappers son,
That would be in Bryan's wheelhouse. May want to re-post this on the APPLIED BALLISTICS STRING on this site.
 
thank you for your help sir. People like you in the berger organization make this company one of the finest companies in the firearm industry.
 
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