Some of my pens work just fine without posting the cap on the end of the pen. That is true for my Montblanc 146 and 149, and definitey true for my Pelikan M800. I've started writing with one of my older Pelikan M600 pens. Because the previously mentioned pens are longer and heavier, they feel fine in my hand without a posted cap, but the M600 doesn't feel so good - too light and a tad too short. When I try to post the cap, it is loose, even if I push it firmly over the barrel. I love this pen; it writes so smoothly and reliably. So what can I do to make the cap fit firmly over the barre? I don't want to use a rubber mallet to post it! (just kidding)