Krieger 4groove or Bartlein 5R for 7STW build?

[Popapi]

8.5 it is! I'm thinking Bartlein can do a 8.5.......

 

[Edd]

What contour do you want?

 

[gamehawker]

8.5 it is! I'm thinking Bartlein can do a 8.5.......

Good and right choice! I would definitely go with an 8.5" twist not a 9" twist for your build to shoot 140 to the 180VLDs….

If it were me and I was going to shoot the heavies I would go with an 8 or 8.5 twist. It doesn't cost any more to go with an 8 and it will not hurt your accuracy if you choose to shoot the lighter bullets as well.

Great advice!

 

[Popapi]

Guys do you feel a 8.5 twist will stabilize the new 195s that Berger will be coming out with?????

 

[IdahoCTD]

If I was ordering a barrel I'd do a 8 twist rather than a 8.5 twist to make sure it would work for the 195's. A 1/2" faster twist won't matter at all shooting 180's or 168's even.

 

[Edd]

I too would order an 8" twist.

I had an 8.0" twist Krieger that I was going to use for the 195 gr bullets. When I gave up on the bullets and switched to a 30 caliber, I sold the barrel to another member of LRH. He recently told me that he was getting one hole groups at 100 yards and 2" groups at 600 yards with 180 gr bullets.

 

[Popapi]

Called Krieger and it's to late to change 8.5 it is!

 

[WildRose]

Called Krieger and it's to late to change 8.5 it is!

At STW velocities I think you'll probably be fine. At worst you'll have to probably top out at the 180-185 class bullets.

I don't see anything on Berger's site giving details on 195's but if anyone has the info you can plug it into their twist rate/stability calculator and figure out pretty close if the 8.5 twist will work at 2900-3000FPS which is probably not too far off from a reasonable velocity.

 

[Popapi]

No information as of yet did hear the bullet will be out early fall!

 

[Edd]

At STW velocities I think you'll probably be fine.

Velocity is a poor substitute for barrel twist rate. It would take an additional 1300 FPS to equal a 1/2 inch increase in twist rate.

 

[bigngreen]

I ran the stability on the 195's the other day and a 8.5 will get it done if you have a little elevation, an 8 twist would be better if your near sea level. I've been using 8 and 8.5's only this year for 7mm builds and you will see an accuracy advantage with the 180 Hybrid as well.

 

[Popapi]

I ran the stability on the 195's the other day and a 8.5 will get it done if you have a little elevation, an 8 twist would be better if your near sea level. I've been using 8 and 8.5's only this year for 7mm builds and you will see an accuracy advantage with the 180 Hybrid as well.

Awesome thanks for the information! Can you elaborate on the stability test?

 

[bigngreen]

Awesome thanks for the information! Can you elaborate on the stability test?

Just ran the stability on the Berger calculator, a factor of 1.5 or better will give you good full stability and maximize the BC, below that you could start dropping of some BC.

 

[Popapi]

I gotcha Big thanks so much guy!