Chances are stick built it anyway, he did all of the chamberings and stock work.
He builds an excellent gun.
If it's low mileage barrel it's worth quite a bit.
The 300 Jarrett is pretty much cooked at 700 rounds.
Is it a hunting weight gun? Or is it a heavy barrel gun?
If you post a pic I can help you with value.
What action is it?, trigger? Stock?
It's loaded from 8mm rem mag brass, or 7mm stw brass you have to step the neck up to .308, and fire form before loading full power.
Retumbo and h1000 is excellent in it and if you shoot 155's it will go nearly 4000 fps.
I have seen deer with 10" holes blown through them.