So do you think the problem is also that the targets are too flexible - thus absorbing the impact 
Filing the lip is interesting - never tried that !
Great advice Ian 
Yeah - apparently the targets can flex and basically bend backwards without the lip falling off the shelf. I find it hard to believe, but I have noticed that the softer the targets the worse the problem tends to be. The old Stern 'scrabble tile' design are definitely stiffer and drop heaps better.
cheers
Ian
