Sperm oil primary use for gunmakers has been to harden and temper flat springs, such as gunlock mainsprings. I was in America 10 years back at the Las Vegas gunshow and found some for sale. Sperm oil has just the correct flash point for making springs, however peanut oil has a similar, but higher flash point and works very well.

Originally Posted By: Bob Jurewicz
After the Rangoon oil thread I can't wait to hear about this one.
I have a 1/2 Pint of Brownell's "SPERM OIL". What do I have and what is is used for???
Thank you!!!
Bob Jurewicz