I was putting together a size comparison between the Rohrbaugh R9s and the Kahr PM9 for a fellow over on the Seecamp forums and I noticed something odd. Both guns are almost identical over-all lengths (5.2" and 5.3") but the R9s is listed as being a little more than a quarter inch shorter over-all (3.7" vs. 4"). When I did the comparison pics, as you can see below, the R9s was actually ending up a tiny bit taller than the PM9. I checked and rechecked my measurements and figures. I kept coming up with the R9s being taller. After a few minutes of figuring I determined that Rohrbaugh does not include the sights or the mag/mag release in the over-all height of the gun. It is the only way to make the ratios work out. Kahr measures the PM9 from the top of the sights to the bottom of the mag plate (a much truer figure). This might be something that some people might want to consider if you are looking into buying either of these guns. Both guns are very light. The R9s is just under 13 ounces and the PM9 just at 14 ounces. Both guns hold 6+1 rounds. However, the Kahr can hold 7+1 with the finger extension and is +p rated if that concerns you. Here are the comparisons. I did it both ways since it is hard to see one under the other because of the very similar sizes.