In 1979 Ruger first offered their 1st design heavy barrel Security-Sixes which had very little barrel taper compared to the second design..also this was the first year that Ruger was installing their Big Grip target grips. Ruger did this because of some complaints of the first design old frame Security-Sixes climbing up in the hand during rapid firing and this was caused from the lower sloping upper frame underneath the hammer. But despite the newer security-Sixes with the raised frame in this area it wasn't until 1979 with their new Big Grip that had given maximum control of this issue. Here are some photo's of this pair of HB Security_Sixes: