If this is to open a safe with a lost entry code, I'd just forget it...have it drilled/cracked/broken into and buy a new safe.
It would take upwards of 100 days to try all 1,000,000 combinations, without counting time to...ya know, SLEEP...EAT...SHOWER....WORK. 100+ days if you did NOTHING but enter a code every 10 seconds, 24 hours a day.