My Trail NP XL does not group well with Premier HP 14.3 grains, but shoots dime size groups at 25 yards with GTO 11.75’s. Could the light pellets exiting the muzzle before the vibrations start? Any ideas why this difference?
I'd suspect it's partially a pellet consistency thing. CPHP's aren't as consistent as some other pellets. If a bore happens to be a bit tighter than average, they can perform very respectfully. I have some airguns that love them, some hate them and a few that are mediocre but good enough for plinking out to 30 or 40 yards...
Got a deal on a Trail NP XL .22 when neighbor couldn't find accuracy with any ammo. My search was fruitless until stumbled on H&N Sniper Magnums (17.90 grain.) H&N discontinued Sniper line so at a loss until found JSB 18.1s did well @ 22 yards. Tried H&N Barracuda Greens (12.96 grain) they shot off into the unknown with a .22 PB rifle crack. Mine prefers 18-grain range pellets, higher and lower grain weights don't hold accuracy. WM
You will find that the GTO shoots well in a fairly large variety of rifles. As does the Barracuda Green. They are expensive pellets, however if you take the time to weight them you will find great consistency in weight, cleanness, and almost perfect formation of each pellet, this all contributes to accuracy.
Mine is 10plus years old and I can't find any decent accuracy with it. I think my problem is the terrible trigger. I just got some 18 H&N barracuda's extremes to try but not holding my breathe.