X failures within X total rounds

Some folks expect a good gun to not fail. An example is 0 fails in 1000 rounds.

Some folks have more realistic expectations. My SAS II UL has 8 failures with 1241 rounds. Awhile back, someone asked me how reliable the UL was, and, at the time, it had 6 fails at 650 rounds. Someone else balked at that until I provided the percentage (0.92% failure rate). Percentages will always trump raw figures, IMO. I just use a percentage and not even a formula ( I use Google to generate the percentage). The percentage gives me a better understanding of how soon a failure might recur - it's not rocket science, but wanted to share.