That sleeve is not a pillar, it is a spacer. It establishes the distance from the top of the mag box to the receiver. If you glue it to the stock, it becomes a pillar. Same thing at the front; not a pillar. WH
Mine is a shilen bbl 6mm and its great along with a somewhat adustable trigger. Sorry yours is a POS but I have a problem as to WHY? Mine is fine I have that mark 10 in 6mm and an earlier 98 in 6BR Remington. I really like them bothMine was made in Yugoslavia... Or was it Czech?..need to look it up.... absolutely garbage compared to my brothers FN. Was yours a magnum?
Edit: It was Zastava in Yugo. The barreled action would be a tomato stake if I still had it.