Finally did the sums after a year of bulk-loading. 30.5m tin of HP5 = 18 rolls of 36. Current tin price works out at £6.10 a roll versus £9-ish retail, so roughly £52 saved per tin — minus the loader (£25 once, eBay) and cassettes (reusable). Verdict: worth it if you shoot a lot, but factor in the one roll per tin I ruin by loading it fat-fingered in a hurry.
The hidden bonus is custom lengths — I load 12-exposure rolls for testing developers and it’s transformed how quickly I can run comparisons. No more sacrificing 36 frames to find out a dilution is wrong.
Counterpoint: I stopped bulk-loading after a felt trap scratched a whole roll of one-off negatives, tramlines end to end. Replace the cassettes regularly or use the reloadable metal ones. The £3 a roll saved wasn’t worth that afternoon.