Gunbreaker

Hey guys i recently fired 100 consecutive shots from my pistol and all of a sudden the slide was'nt sliding all the way back to rechamber a round and so I removed the mag and got rid of any jammed BBs; there were not any. Then after dry firing it once it didnt cock all the way back. I dont wanna force it all the way forwards and I field stripped it and didnt notice anything strange, any ideas?