Through that low period they used a variety of actions, often availability and customers budgets were determining factors.
I once owned a 416 built on a BRNO 602 action, and stocked with what I percieved to be a pre inletted piece of Fence post trying to pass as Walnut!!
This era/period was not Rigbys finest, nor was it for the trade in general. Thankfully Rigby appears to be back on track in 2015.

Best
Eric