The barrel length is not fixed, but is largely determined by caliber rifling length requirements. The rifle pictured on the website is a 28" overall barrel length with 20" of rifling. 26"-30" is a common length due to most long action cartridge rifling length requirements for proper velocity, but many short action calibers can be quite short with minimal, if any, velocity/performance loss. Really, any customer requested overall length within reason can be built. Overall length is determined by the customers desired rifling length + 8".
Finished barrel diameter is is 1.25", which is actually the exterior of the titanium sleeve over the barrel. The 28" barrel in .308 on the website weighs 3.8 lbs, which is lighter then the factory desert tech barrel if I remember correctly.
We can chamber any caliber that reasonably feeds from the Desert Tech magazine, though this is tentative as we currently only have experience with .308.
Please let me know of any other questions you may have.
Frank Charuk
General Manager
Shop- (832)759-9634