IF you count how many shots that manage to dribble out the barrel in the general direction of the target, then it is probably much more than 70 shots.
If you count only the number of shots that are within 3% (or a more liberal 4%) of max. velocity, then it will be a whole lot less than 70 shots (and they do not advertise 70 shots for the .25 versions...forget the number, but its less than 70).
There is some adjustment built into the system (is kind of hidden and hot really adjustable unless taken out of the stock, but there is a spring tension adjustment). How low you have it adjusted to shoot changes the shot count as well, but lets consider the expected real-world numbers from an out-the-box Hatsan PCP.
Will use this calculator for estimates:http://calc.sikes.us/1/index.php
IF you plug in 3000 start fill and 1900 as the end pressure (a pretty liberal pressure range)
180cc as the volume (although they make long tubed versions as well as the standard 180cc tubes)-
use 26gr. as a "average" .25 pellet and use 850fps as the velocity.
Can keep plugging numbers for the shot count into the equation until you get a bar-cc/fpe efficiency rating of about 11 (which is a pretty good efficiency).
Doing that, come up with 28-30 shots. From past experience, that would probably be the best real-world shot count within a reasonable velocity variation (meaning a variation low enough that you wouldn't notice the shift in vertical at short ranges like 25yards).
.177 Example: a simple Pneuma, but from what I can tell, all the PCPs use the same valve system so it could be useful to other models. Has been farted around with and adjusted, but running on stock parts.
IF you keep to 4% of max, then could count 60 shots inside of 4%'
IF you keep to the 3% max, then about 48-50 shots.
NOTHING adds to shot count like OVER FILLING. Once you get close to valve lock, it takes an amazing number of shots to bleed off enough air to let the gun get back up to normal speeds. Once overfilled this gun by 35 BAR (not over MAX pressure, just over the pressure it had been set to run at) and it took me 60 shots before it got to the expected curve...while they were not "useful" shots in that they shot way-way low, could count them as "shots" and claim 150-175 shots per fill for the same gun as above.