Quote from: Motorhead on June 17, 2021, 02:32:28 AMyes ... that inconsistencies in path size hurt more than too small or too large.The rotary ball valve controlling velocity is a major stumbling path in that design.Valves transfer path exiting throat all the way to and including barrel really optimize in these @ sizes for more powerful field duty type tunes..177 cal @ .140".22 cal @ .165".25 cal @ .180"GETTING said sizes not so easy on some PCP'sIf I might ask-what you would consider a more powerful field tune in .22? Jesse
yes ... that inconsistencies in path size hurt more than too small or too large.The rotary ball valve controlling velocity is a major stumbling path in that design.Valves transfer path exiting throat all the way to and including barrel really optimize in these @ sizes for more powerful field duty type tunes..177 cal @ .140".22 cal @ .165".25 cal @ .180"GETTING said sizes not so easy on some PCP's
Quote from: JuryRigger on June 17, 2021, 12:40:30 PMQuote from: Motorhead on June 17, 2021, 02:32:28 AMyes ... that inconsistencies in path size hurt more than too small or too large.The rotary ball valve controlling velocity is a major stumbling path in that design.Valves transfer path exiting throat all the way to and including barrel really optimize in these @ sizes for more powerful field duty type tunes..177 cal @ .140".22 cal @ .165".25 cal @ .180"GETTING said sizes not so easy on some PCP'sIf I might ask-what you would consider a more powerful field tune in .22? Jesse 30 fpe and above
The 30 FPE was the answer to the question of what was a "more powerful filed tune in .22".... In similar guns (barrel length, pressure, etc.) that would be ~20 FPE in .22 cal and ~40 FPE in .25 cal.... Personally, for field tunes for pellets, I would use slightly larger ports in .25 cal (0.188").... For slugs, and with the intent of more power, I would be using as close to bore-area porting as possible in all calibers.... but only if the probe is also retractable.... otherwise I would just match the chamber area (bore area minus probe area) with all porting.... and about 10% larger than that for the valve throat....Bob