aa r85a1 problem

[lemon191]

right i got a Army Armarment R85A1 second hand from a guy on here, he said it had some stopping issues but he said it still worked when i got it i managed a few rounds on auto then the auto just gave up and doesnt do anything however semi seems to work 96% of teh time with only the odd stoppage

he said the gun has had a new piston installed and the blowback disabled. i know this gun is known for some crap reliability and tbh if its not a easy fix then ill be happy to use it as a display model for the wall

so any ideas on things to check? ive got to admit ive never opened a airsoft gun before aswell so nothing to complicated i hope

cheers

lemon

edit: just to add i have checked that the battery is well charged