A 308 dia bolt for the AR15 can be had here for $65.
http://www.mgimilitary.com/store/ind...85b8f6d3ddd69d
The spectre is aprox .23 shorter than the BR. That can be fixed by a slightly shorter chamber & reducing the neck length on the BR case. I have a modified 338BR reamer to be here this week. I hope by early march to have all the issues resolved. The AR10 with its 308 mag would be best for the BR case but I dont want or need that much gun. The last time I saw some 338Spectre brls for sale they were in the $400 range. No thanks. If you want a specter contact Marty at Teppo Jutsu. See what he charges. If you would like to look at the BR case, contact me & I can give you some #s on a 338BR brl/upper. I am also looking at using the 44AMP brass. This matches the spectre lenth. Lots of options here.