Understanding Texan LSS CF 457 Valve Dump Conditions

Hi All,



New to the forum and new to big bore air gunning in general. I come from a lifetime of power burners of all shapes and sizes. I recently got an Airforce Texan LSS .457 with the CF bottle, and finally had a chance last weekend to take it out and try it.

The tank came filled at about 2600 PSI, which I thought was a decent and safe pressure to start out with. I'm using NSA 350 gr. HPBT slugs. Power setting was at 3/4 full.

My very first shot was was a valve pump down to zero pressure, and I was NOT prepared for such noise and recoil. Second shot, filled to a little over 3000 PSI, I watched the slug drop about 8 inches in 20 yards - my guess was about 300-400 FPS. So I then turned up the power dial to full for my third shot, and dumped the entire tank again down to empty. This time I was in a sitting position and it knocked me onto the ground and got a nice bloody gash in my nose from the scope bite.

So my question is - are there certain pressure and power dial setting ranges I need to be wary of when using this general weight of slugs? What might there be to look out for to check if there's an issue with the valve itself?

Thanks in advance!