Here is my take. I have a M22 with extra plenum and did some porting. I tuned for JSB KO 24.39 slugs. First find at what speed you get the best uccuracy.
Slugs like a higher reg pressure so that the velve will close quick and elliminate muzzle blast. It is more important with shorter barrels to have a higher reg pressure. My gun is sub MOA at 880fps. It can take a wile to figure it out. I start at 150bar and set the HS to my desired speed and shoot it of the reg. If you get a big speed increase below the reg pressure, you can drop it with 5bar at a time. Note your ES above the reg pressure and speed below the reg pressure. It is nice to be able to go below the reg pressure with plenty of usable shotes. If you get a big speed increase, drop the reg by 5bar at a time and test again after setting the HS to the right power.
I'm am able to get all my shots that's above reg pressure between 880 and 884fps at 145bar. At 150bar my ES goes op to 12fps and too low reg pressure as well, and accuracy gets worse at to low reg pressur. My sweet spot is 145fps. (My good Huma reg allso helps). Below reg pressure it slowly goes up to 890fps and then drops back down to 880 and suddenly to around 850fps at around 125bar. Perfect! And then even my China gun can out shoot most of the much more expensive guns. Good Luck!
Slugs like a higher reg pressure so that the velve will close quick and elliminate muzzle blast. It is more important with shorter barrels to have a higher reg pressure. My gun is sub MOA at 880fps. It can take a wile to figure it out. I start at 150bar and set the HS to my desired speed and shoot it of the reg. If you get a big speed increase below the reg pressure, you can drop it with 5bar at a time. Note your ES above the reg pressure and speed below the reg pressure. It is nice to be able to go below the reg pressure with plenty of usable shotes. If you get a big speed increase, drop the reg by 5bar at a time and test again after setting the HS to the right power.
I'm am able to get all my shots that's above reg pressure between 880 and 884fps at 145bar. At 150bar my ES goes op to 12fps and too low reg pressure as well, and accuracy gets worse at to low reg pressur. My sweet spot is 145fps. (My good Huma reg allso helps). Below reg pressure it slowly goes up to 890fps and then drops back down to 880 and suddenly to around 850fps at around 125bar. Perfect! And then even my China gun can out shoot most of the much more expensive guns. Good Luck!
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