I have a CZ-550 American in 6.5x55. The factory barrel is 1 - 9" twist. I know there are a whole host of other 6.5's out there but don't know how common the 6.5x55 is in the family. I would suppose that the 1 - 9" is optimal for the 6.5x55 as this is the factory choice.

Question:
I was wondering what twist rate the 6.5 shooters out there employ regardless of cartridge.

Eric

Choices:
< 1 - 7"
1 - 7"
1 - 8"
1 - 9"
1 - 10"
> 1 - 10"

 

I voted 1:9, but it depends on which round and purpose. For general hunting the 1:9 is more than adequate and in my rifles handles everything up to and including the 140 hunting bullets. For the long target bullets 140 and above I opted for 1:8.

It also depends on the velocity capability of the cartridge in question. In the 6.5 Grendel for instance a 1:8 is needed for best effect although those that shoot only the lighter bullets can and do effectively ise the 9 and even a 10 inch twist. A 6.5x284 or 264 Win Mag may have differet requirments.

I have a 1:9 in my rebarreled M70 6.5x55, 1:8.7 in the Blaser R8 6.5x55, 1:8 in the Sauer Model 200 6.5x57, Encore 6.5 JDJ and Contender 6.5x30-30 AI Have some load developing to do, but I'm looking to go with the 160s in the Model 200...

When it comes to ballistics there never is a simple answer is there. I was hoping to use the CEB ESP Raptor with the tip insert but it won't stabilize in my 1 - 9". It will without the tip though.
Eric

My 6.5-06 has a 1:8 twist, selected for 140gr bullets. I note that Hornady 140gr A-Max list 1:7.5 on the packet as the twist rate for their bullet although these are very accurate in my 1:8 barrel.

These days I recommend a faster twist in just about every build I do. It won't be long before lead core bullets go the way of the Dodo. The copper, guilding metal, monometal bullets are a good deal longer and require a faster twist. Heck, Berger recommends an 8" twist for even their 130 gr hunting bullets.