Ken,
The .30 stock does indeed work just fine my old friend. On my old home made vac rig I started using the .30 stock mainly out of impatients with waiting for the .40 to get hot enough to drawdown properly. You'll end up with a very thin shell of a piece but with careful handling works great. I'm looking forward to seeing the results and especially the near full internal structure.
Keep up the outstanding work.
Highest Regards,
Gregory Jouette