Can I get away with a carbine position port and cycle?

[rumlover]

Hey fellas,

I want a whisper upper but don't want the expense of a custom rig leaving the Model1 or Olympic Arms options (if there are others, I'm not aware of them). The twist is right for the heavy subsonics, but they only offer the port in the carbine position. I'm not interested in high velocity ammo, just subsonics for grins and giggles.

Will the carbine position uppers cycle with subsonics?