I see them regularly in the $450 to $500 range. A big factor seems to be the number of mags included. I just saw one locally in excellent condition with one mag for $399. I ended up with two mags in like new condition that probably came with that gun for $50 each. Mags seem to regularly get sold off separately so the dealer may have more than what comes with the gun.
Also, the gun is known for it's very heavy DAO trigger. This can be improved in a huge way by installing a Wolffs reduced power striker spring. I would recommend the reduced power spring over clipping coils. The pull is still long but is much, much lighter. This gun was designed for use by the masses in the event of an Eastbloc invasion with the "military" version having a stock that converted the gun to a tri-burst. The striker spring is very heavy as the gun would have probably been used with military subgun ammo which can have hard primers. Also, it is quite true that deep grooves in the rifling allow gas to vent around the bullet as has been stated. I suspect that this was also necessary with the use of hot military ammo especially with a straight blowback.
My understanding is that the break point after the long draw, a definite potential holding point before the trigger breaks, is there to allow more accurate fire. If it wasn't designed that way it certainly serves the purpose nicely. It could utilize a wide range of plentiful 9mm ammo, had a minimum of moving pieces, extremely simple manual of arms, and I would predict that it would fire for a long time very dirty.
I enjoy shooting my VP70Z . It's actually a successful and ingenious design when one considers what the gun was designed for. Fortunately it was never used for it's intended purpose, which basically would have been WWIII. HK's mistake was failing to reduce the power of the striker spring in the commercial versions. They also failed to fill in the slots in the grip/frame for the attachment of the stock in the first pieces to reach the US which caused the ATF a hissyfit. If you look at the rear of the frame at the top and bottom of the grip you will still see the outlines of the stock attachment slots which have since been filled in.
The gun often gets a bad rap which fails to consider the original purpose of the gun and the significant improvement that can easily be made to the trigger. The gun is actually very shootable.
