So I have been asked to help identify a weird no4mk1 (F)

It's marked 10/47 PF 2XX. (XX) to obfuscate the last two numbers btw.
It appears to have a enforcer style magazine with a weird ported barrel, unsure of the caliber.

Can anyone help me out?
Information
Warning: This is a relatively older thread
This discussion is older than 360 days. Some information contained in it may no longer be current.