When I first got my Lyra (mostly same as Daystar) I pulled the barrel so I could polish the bore. When I pulled the barrel I saw that the barrel o-rings were shaved from the sharp, not deburred holes in the block. So. I also pulled the air cylinder and found the same. I deburred all the holes, installed new o-rings and polished the bore. I did all of what I just wrote for the Daystar also.
Next, I went to the trigger. I like a single stage trigger so I modified the trigger mechanism to make it a very crisp single stage that breaks at 8oz. Too difficult to try and write in words what I did. But, it involved removing the first stage spring all together and adding a shorter and lighter weight spiring in a different location within the trigger levers to make the trigger single stage. Both my Lyra and Daystar have the trigger modded in the same way and both rifles have thousands of shots fired with no trigger failures.
I wanted to shoot 18gr pellets at 890fps. I wanted 30-shots per fill with the flattest shot-to-shot velocity I could get from an un-regulated rifle. After initial testing I realized the rifle's hammer spring is too strong to achieve a 'bell curve' tune with the weight pellets I wanted, at the velocity I wanted. So, I cut the hammer spring to 3.125" (stock was about 3.750"). Making the spring change got my rifle to where I could get the tune I wanted as described above.
My tune is a fill pressure of 195bar, AEA18.3s, 890fps. I get 30-shots with a maximum ES (extreme spread) of about 8-10fps. My first shot velocity matches my last shot velocity.
Beyond that I just lubed the bolt and checked all fasteners for torque. Also, added Loctite 222ms (mild) to fasteners that needed it, and wheel bearing grease to fasteners that need lubed.
Both of my Reximex 'long' rifles have the same tune and both rifles shoot 5-shot groups that average 1.5MOA at 50yds with many groups going into 1/2" and some groups even smaller! The Lyra is very slightly more precise shot-to-shot than the Daystar but they are both very accurate and reliable rifles!
Hope your new Daystar works out for your needs!
Reximex Daystar.
Reximex Lyra.