7.62x39mm Finn Helmet Test


I am looking for information about Finnish made 7.62x39mm cartridges that are reportedly “Helmet Test” loadings. The first is made up from a fired case with a very heavy round nosed projectile and the second looks like a standard ball load but the jacket attracts a magnet. This second cartridge has “Helmet Test” printed on it and is reportedly steel cored. The first was sold as a “Helmet Test”. Two valid variations? One earlier than the other?