Ted gunman is correct and of course he was there at the factory.
From an engineering standpoint a single small hole in the breach face is far cheaper to produce than a larger threaded one in the cost of tooling alone, not to mention its matching other half. Also the 700 was designed made and sold to meet a price in its intended market so the added cost of disk set strikers would not be considered I am sure.
As for repair of a broken striker I have seen a couple of repairs on hammers. Both repairs consisted of removing the striker remnants drilling a hole in the hammer face, fitting a replacement striker having a collar which contacted the hammer face to improve mounting stability. As the striker is positioned off centre of hammer centre line positioning is critical, on both repairs it looked like the strikers where held in place with silver solder rather than brazing.
