%0 Journal Article %T Upper bounds on packing density for circular cylinders with high aspect ratio %A W£żden Kusner %J Mathematics %D 2013 %I arXiv %R 10.1007/s00454-014-9593-6 %X In the early 1990s, A. Bezdek and W. Kuperberg used a relatively simple argument to show a surprising result: The maximum packing density of circular cylinders of infinite length in $\mathbb{R}^3$ is exactly $\pi/\sqrt{12}$, the planar packing density of the circle. This paper modifies their method to prove a bound on the packing density of finite length circular cylinders. In fact, the maximum packing density for unit radius cylinders of length $t$ in $\mathbb{R}^3$ is bounded above by $\pi/\sqrt{12} + 10/t$. %U http://arxiv.org/abs/1309.6996v1