Without a picture it is hard to say for sure. That being said, it is probably a Dr. Grabow pipe.
Could also be either a Ring Master or a Waldorf but my money is on Dr. Grabow as they have been around for many years and are still made today so there are tons of them being bought/sold/traded.
Here is a great website to look up pipe brands based on symbols and letters on the shanks and stems.
http://pipephil.eu/index.html
Navigating the site takes some getting used to but once you have it down it is fairly easy to find pipes.