This morning I swapped the stocks between my 97kt and the 77k. Had a few stumbling blocks. On both the front trigger guard screw was so tight that it actually was frozen into the block that screws to the receiver and keeps a sliding I guess cocking or safety piece in place. After I got the block loose, I figured out where metal ring (spacer)that went in that sliding piece to keep the block from screwing down so tight as to stop it's movement went, it had dropped out. Got the block screwed in withe the spacer in place. On the 97kt the actual trigger guard screw was so tight I had to use a pair of vice grips on that block to loosen it from the screw to get the trigger guard out. Finally got the stocks swapped, and tested the guns for function, perfect, so I did things correctly. I did this in anticipation of a CS 600 stock I have on order, not wanting to fool around with two guns and three stocks at the same time. I did discover rather quickly that the thumbhole stock is not made to use with iron sights, but that will be ok for a few weeks until the new stock arrives.