ML100 series ?
Wouldn't touch one of them with a bargepole, certainly not bulletproof. They're only there to enable HP to capture the people who buy on price, trying to stop them going over to old Smell who specialise in selling tat to that end of the market.
The ML100's aren't terrible, but they're nowhere near as robustly built as their elder cousins up the range.
ML300 series or above, definitely bulletproof. You could be forgiven to think they line them with lead sheeting given their weight !