Air rifle help ..

[zzr1100]

I've taken the barrel off the rifle and had a good look .. Seems ok .. Surprised at how many grooves and how tight the rifling is compared to My old hw80 ... Gonna shoot next week without the mod to see if there is a difference ...(mod seems ok also)
IF the pellet it catching the mod I'm not sure on the way forward .. The mod is attached with a "collar" held on with a couple of tiny Allen screws ... I can't see how this could be mid-aligned ?? But then .. I'm no gunsmith !

[zzr1100]

Mod removed and a massive improvement .. Nice tight groups with perfectly round holes ... Now to work out what's wrong with the modifier .. Anyone got any experience with Parker hale mods ?