Designing a game call can be a very challenging prospect. The sound has to be just right, and yet it needs to be simple enough that anyone can use it to make an effective call. Using a corrugated rubber tube for a game call can allow the user to fluctuate tones in ways that closely mimic a live deer, moose, or elk.
Bellows for game calls can range in size from 5/8″ all the way up to 2″, depending on the type of animal and the specific type of noise being targeted. An elk bugle, for example, requires a large tube whereas a deer grunt can be quite small. The difference in the pitch, or distance between the convolutions, is equally as important as the diameter, as both will affect sound.
Game calls are going to sit for long periods of time when not in use and may be prone to cracking, brittling, or dry rot if the wrong material is used, and they also need to be as flexible and stretchable as possible. For those reasons, something like an EPDM rubber is a good choice, rather than a thin, hard, blow molded plastic. Softer molded polymers like silicone or urethane can be good options as well. The key is to focus on UV, O-zone, and weather resistance, as well as cold temperature performace since many times these will be used in near or below freezing temperatures.