I put my boresighters in the mussle (bought them thinking i could place them in the breech but woke up one night and hit my forehead

) and they seem to give a hint to where the shots will land.
I messured up my barrels and they were about 26,2mm in the breech and 20,7mm in the mussle.
Thats quite a lot and then i already have spread the barrels about 2mm. Anyway now the lasers come 24cm crossed on about 100m, and they cross at only 3,5m from the breech.