look at this pic, notice where a little "relief" is cut into the straight end:
http://www.aerostich.com/aerostich-t...m-tar-arn.html
i have a set of these, and if you pay attention to keeping the relief on the rim and not slipping in, no more pokes.
i've also modded a generic steel set of irons with a little grinding and it does the same job......