Let's talk about the bore size in a duck call insert and why it is so important. First off the bore size lets the sound that was built into the insert out. Its second and most important job is then to create some back pressure. This can vary depending on the tone board math, but as a general rule the large bore the less back pressure and the smaller the bore the more back pressure.
What is back pressure?

Back pressure is how much the call restricts the air exiting the bore. That's a little bit of summed up duck call science. The call nerd in me could write pages about how I believe all that stuff works together, but I think most of you guys just want to kill a duck with dependable call and not read about the whys and whats of the deal.

So why is bore size so critical to you guys out killing ducks? It should be the number one factor when looking at a new call. I can type up some ultra cheezy call descriptions with words like "spittin" feathers, the ducks built it and whatever else they use, but it is a terrible way for you to pick a call. Instead we want you to know how the call was designed to perform and if the call will be a good fit for you. We want to help make waterfowling better and earn that spot on your lanyard.

We build four sizes of exhaust bores in five models of duck calls. These four bore sizes cover a wide range of volume and back pressure.

We want you to think of duck calls like this, most volume to least volume or least back pressure to most back pressure.

Conartist Hand Cut and LT Hand Cut: Most Volume -least back pressure--FULL RANGE CALLS

Fuze Hand Cut- Upper midrange volume- Moderate Back Pressure---upper midrange call

Sinner- Lower midrange volume- high back pressure---midrange call

QT-Least volume-highest amount of back pressure--very quiet running call
Now what does that all mean when picking calls?

If like to run a call hard and aggressive you want a call with low to moderately low back pressure and good volume. Conartis Hand Cut, LT Hand Cut and Fuze Hand Cut.

If you like to call softer but have little more volume every once in while you would want to be in the midrange calls with more back pressure and less volume, Fuze Hand Cut and the Sinner.

If you want to be as quiet as possible and like to make a lot of soft notes a call with a small bore and maximum back pressure will do that the best, QT-Quiet Timber.