Gunsmithing Twist for 6.5mm and 7mm barrel?

[Agunner012]

What twist would be best for a Rock barrel in 6.5mm shooting a 142 SMK bullet, and a 7mm Rock barrel firing a 175 SMK bullet?

TIA

 

[THUNDERBOLT68]

Re: Twist for 6.5mm and 7mm barrel?

1-9 FOR 7MM 1-8 FOR 6.5

 

[427Cobra]

Re: Twist for 6.5mm and 7mm barrel?

Yep

 

[demarpaint]

Re: Twist for 6.5mm and 7mm barrel?

Will an 8.7 twist work for the 7mm? Or is the 9 still the ticket?

 

[pwc001]

Re: Twist for 6.5mm and 7mm barrel?

8.7 is what Rock recomended to me.

 

[demarpaint]

Re: Twist for 6.5mm and 7mm barrel?

I thought I'd ask only because my 7 WSM is using a 9 twist, then someone mentioned 8.7 twist and the tilt light came on.

 

[shoot4fun]

Re: Twist for 6.5mm and 7mm barrel?

My Broughton in 7WSM handles 180 Berger VLD very well with a 1 in 9.

 

[txlimey]

Re: Twist for 6.5mm and 7mm barrel?

For a Rock barrel in 6.5mm shooting a 142 SMK bullet i would go with a 1 in 8 twist rate. 1 in 8.5 is fine for lighter bullets, but for the 142 SMK you need the 1 in 8.
The heavier bullets and faster twist rate perform better at longer ranges. Though you might find a lighter bullet and a 1 in 8.5 rate better if you are shooting at shorter ranges. I assume as you are asking about 142 SMK's that you have already made that determination, and are shooting at longer ranges.

 

[USMCj]

Re: Twist for 6.5mm and 7mm barrel?

1/8.7 here for 7WSM

 

[42769vette]

Re: Twist for 6.5mm and 7mm barrel?

i have a sheilin 28 inch 1-8 twist 260 that loves 142 smk bullets

 

[crumpmd]

Re: Twist for 6.5mm and 7mm barrel?

My Kreiger 6.5 1-8.5 twist shoots 142SMK very well. Not to say a 1-8 won't do it better, but bugholes are bugholes. And I quit the 142 anyway in favor of the 139 scenar