I do know from watching some planet eclipse youtubes that from the factory their markers are 'over lubed', perhaps youve blown some of that on your detents or barrel?
Aswell you say you used the same paint, was it from the same box, as althoufh it may be the same brand, it could be older or kept in a slightly different way affecting the balls roundness. X
Have you asked to use his barrel on your lv1? I use a empire nightsick which i was given with my first mini i baught, i think its .691 bore, only reason i use it is if i pull off a bum move and snap it, i wouldnt be upset. The debate of underboring, overboring and improving accuracy is never ending, but the only real performance changing things ive found is a clean marker and the paint i use... X
Also you say your lv1's is has 1000 balls through it, so you may still be 'breaking it in' your fps may be a little more iratic than his, if your shooting one ball at 270fps then one comes out at 290fps i should think that would affect accuracy slighty. By all means if you can afford it buy another barrel, many different views on how they affect things, sometimes you got to try it for yourself...
And tell your mate to stop being so childish and unscrew his barrel... X
Wel if i was you id make the most of your shaft 4 barrel and just buy the boost kit, atleast it makes your marker more attractive to potential buyers if you ever sell it..
If you play mayhems big game this year you may be able to. X
Robo free bit of advics mate ! you ask why the lv1 doesnt have full auto mode on the eclipse page which was funny enough and your now saying the barrell is poor too ??? I think your the first to ever notice an issue with the bore size that it makes such a difference in the woods. 99.9% of people will stick with the standard barrell