1/7 Twist Rate on .309 JDJ, SSK Barrel. Trouble finding load data.

[Rabbitslayer78]

So I'm in the process of converting my T/C Contender pistol to a carbine. I went and purchased a 22" SSK Shilen barrel chambered in .309JDJ. I really liked the ballistics and power for a medium weight carbine. However the twist is 1/7 , which is pretty fast for a .308 cal bullet. Unless it's a big pill. 200gr plus. I understand the JDJ is not pushing the max velocity or pressure to keep things safe in a Contender frame. I emailed SSK about the twist. I was told that barrel and twist will stabilize from 150gr on up. So my question is where should I start in selecting the proper components to begin load development? I was thinking of a 205 Berger or EldX. Any insight would be greatly appreciated. Thanks.

 

[Mike Casselton]

Don't worry about the twist rate.

The 309 is an almost exact duplicate of the 308 Winchester. Although it operates at a lower pressure to prevent damage and stretching of the Contender frame.

You can also use 308 Marlin data as a place to start. Just be aware of the pressure limitations on the TC frame.


Are you going to use the carbine as a long range toy or are you using these heavies for hunting?

If you're just hunting with the rifle, I'd suggest using 150-180gr bullets.
With those weights, IMR 4350 and either of the 4895 powders will do all that you need.

 

[Rabbitslayer78]

Thank you, yes I'm just looking for a decent hunting load. Hunting mainly for Mulies possibly an Elk in the timber type situation, less than 300 yards. The STW is for anything longer. So 180gr are ok with that twist?. Hopefully not ripping the jacket off.