Hi Keith, try the link below it's the PDF manual it has an exploded view.
http://www.umarex.com/fileadmin/Doku...00.00_B_EN.pdf
Though i do believe in "if it ain't broke don't try and fix it"
Try the simple things first a cotton bud with some barrel cleaner to clean the mags the do the same with some Pellgun oil, used pellgun oil on top of the
Co2 capsules to make a good seal and stop the seal drying out. Also put spot of lube on the usual moving parts.
I personally lube my pellets which may help.
also have you tried different pellets, and are they fully seated in the mag.
Hope this helps in some way.
Jason