Bolt Action Port Opening Question

[zog]

I have a question about why ejection ports are designed differently, and what factors make you choose the one you want?

I found two examples - one that looks wide open (this one is a Fierce), and another that has a much smaller opening (Bignorn TL3). I also see that Defiance, for another example, has several options for port size.

 

[Supersubes]

One is trying to make it easy to feed the internal magazine from the top. The other is trying to be rigid for hanging a heavy target barrel off the front.

 

[buffybuster]

Top loading convenience vs Increasing action stiffness.