I’ve seen a lot of complaints about the Fisher Xmark cap not being a secure fit. Here’s how I fixed the loose cap problem on my pen:

I bought an inexpensive kit with a variety of small o-rings, and replaced the stock o-ring with one that was a similar size but thicker. It may be possible to find an o-ring “just the right size,” but the one I installed was a little too thick at first, and I had to file it down so that cap could fit over it. I got careless and dinged the finish a little bit, but my pen cap now fits securely.

I used to carry a Fisher Bullet, but I almost lost it a few times due to the pocket clip not staying in place. I wish Fisher would make a pen with a secure clip *and* cap out of the box, but until then, my modded Xmark will suffice.

Sent from my phone. There are many like it, but this one is mine.