Question?

[nervoustrigger]

I thought the reason for the SSG, is to use it's adjust-ability , to tune/adjust to different psi levels, and to get into the most useful/accurate and safe range, for what ever pellet weight you are shooting, or do you just build for a very narrow range only?

Well, no not really.  An SSG is fundamentally about preventing air-wasting hammer bounce that would otherwise cause the valve to open multiple times, burping air that does nothing to accelerate the pellet.  The fact versions have been developed that allow one to independently manipulate the preload on the hammer spring is indeed very nice but a bit superfluous to its main purpose.

For the purpose of tuning a rifle for a wide range of energy, it's this secondary feature of preload adjustment that is the most relevant.  So we can just talk about a basic hammer spring preload adjuster, or something more commonly referred to as a power adjuster or rear velocity adjuster (RVA).     

It's true that an RVA can give a pretty wide range of adjustability, and in particular makes it super easy to tune a regulated rifle to the velocity knee.  For your purposes, I would say it's good enough to casually play around with a range of different pellet weights but not sufficient to optimize for such a vast range as 14gr to 30gr.  With the longer tube you have coming, you'll be in a good place to mine 30fpe out of it for the 16 & 18gr JSBs.  But if you want to get a 25gr or 28gr pellet solidly into the 800's--roughly a 50% increase in energy--you're going to need larger ports or more pressure or some of both.  And let's say you do that, well now the lighter pellets will suffer.  You'd need such a light hammer strike (low lift and dwell) to keep them from going too fast, and that tends to drive up the ES to unacceptable levels.  So like Bob said, one end of the spectrum would have to be compromised.

[Hoosier Daddy]

There was a very long thread a while back where a member was tuning an HPA QB-79 that may help you. I will see if I can find it and post a link.