A bow like the one you are looking at that is marked 50#, means that at a 28" draw it should pull 50#. The convention is that for every one inch increase in draw length you would add 3# of pull; thus a 29" draw on the bow you are looking at would be expected to be about 53#. This assumes a very linear weight to draw length, so at 27" the bow would pull 47#, at 28", 50#, at 29", 53#, at 30", 56# and so on. The problem that Gil describes is that not all bows have this nice linear progression in draw weight, especially as the draw length increases. On many bows, the draw weight increases much more than that average 3# per inch mentioned previously. This increase is called "stacking". A bow is said to stack when the draw weight to draw length relationship is not linear and smooth. Hope this helps.