Powder Actuated Roof Deck Pin performance with cold formed, strain hardened joist chords

We have recently become aware of an issue affecting the installation of pins through the roof deck into open-web steel joist chords. Apparently, some joist manufacturers have changed from hot-rolled steel angles to cold-formed or cold-rolled steel angles. This process strain hardens the steel, and we are seeing significant installation issues. The installers have experimented with various combinations of pins and charges to no avail. The solution was to abandon the pins and use welds to connect the deck. Are there any suggestions as to how to overcome this problem?