I have a 7mm STW with a 1 in 10" twist. The barrel is a Kreiger 30" HV contour, 4 groove. Will the 180gr Berger VLD stabilize with this? Originally just wanted to shoot the 162gr A-Max but I am wondering about the heavier Berger now.
7mm STW twist and bullet ??
- Thread starter rdm
- Start date
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kiwi3006
Well-Known Member
Berger state 1 in 9 for the 180. But depending on how fast you are pushing it and at what altitude you might get away with it. The 168 berger will stabilise in a 1 in 10 though.
I used the 162 a-max in my 7mm mag and it was awesome, unfortunately they are unobtainable in New Zealand at the moment.
Stu.
I used the 162 a-max in my 7mm mag and it was awesome, unfortunately they are unobtainable in New Zealand at the moment.
Stu.
dirtball
Well-Known Member
Did a quick calculation
7X57 2450 fps with 9 twist = 196,000 rpm
7MM Rem Mag 3000 fps 9 twist = 240,000 rpm
7mm STW 3100 fps 10 twist = 223,000 rpm
Not sure what velocity Berger bases their twist recomendations on, but I would guess it is something less than the velocity you will get from your 7MM STW.
Should be OK , worth a try.
Dave
7X57 2450 fps with 9 twist = 196,000 rpm
7MM Rem Mag 3000 fps 9 twist = 240,000 rpm
7mm STW 3100 fps 10 twist = 223,000 rpm
Not sure what velocity Berger bases their twist recomendations on, but I would guess it is something less than the velocity you will get from your 7MM STW.
Should be OK , worth a try.
Dave
Thanks guys.
Thanks dirtball for running the numbers.
I'm hoping for 3000-3100fps range for 175-180 grainers, if stability holds up. I was going for 3150-3300fps for the A-Max. I believe those to be resonable numbers for the rifle. Wanting accuracy from this rifle not just velocity. I don't mind trading some velocity for accuracy, if it is there. I get way more jacked up about hitting the target than a 168gr 7mm bullet going 3400fps.
Thanks dirtball for running the numbers.
I'm hoping for 3000-3100fps range for 175-180 grainers, if stability holds up. I was going for 3150-3300fps for the A-Max. I believe those to be resonable numbers for the rifle. Wanting accuracy from this rifle not just velocity. I don't mind trading some velocity for accuracy, if it is there. I get way more jacked up about hitting the target than a 168gr 7mm bullet going 3400fps.
