Hmm. If you have a CA valve, I would think that you'd be able to get away with using less
than 800 psi.
I'm thinking the hammer/spring combo is the key, but I don't know which way you would need to go with that. Sorry.
Like you said, the gun and Stab might not be broken-in yet, so you could always just have some fun dry-firing and making lots of noise!