The gauge on the side of an Alias shows LPR pressure, used to feed the solenoid. This is the pressure that drives the ram back and forth, not the pressure that pushes paintballs out the barrel. The Alias doesn't come with a gauge to show that.*
I think the inline pressure is supposed to be 250-300 psi, and the LPR should be at 50-100 psi.
* If you knew this, and you put a gauge on the regulator after you bought it, I offer my humble apologies for assuming you didn't know all this. I am not now, nor was I ever, calling you a newb. This was just my attempt to share information that might help.**
** If you are not the kind of person who is easily offended by information offered in good faith by way of assistance, I apologize for any implication that you were. I have written this after trying to suggest obvious solutions and having had poor responses in the past. My reactions and post-scripts are in no way due to any value judgements arising from this specific post. ***
*** If you hate addendums and footnotes, I apologize for these. They were not intended to give offence, though that is a regretable risk I sometimes run in saying all I have to say. This is the last one, honest injun. Good luck with you gun.