The CSRG had many shortcomings.
Some assembly was with thread fittings that could loosen in use.
Once the guns got hot, there could be failures of barrel return.
Mud could cause the same problem. Mud in the gun shut it down. Guns were issued with covers, which were not to be removed until use was imminent.
The magazines were flimsy, with poor springs. The open side allowed entry of mud.
Ergonomics were poor; using the sights required being at an acute angle, rather than behind the gun. This resulted in an unstable hold, hardly desirable with an automatic firearm. If the sights had been offset another half inch, this problem would have been lessened.
Holding the gun as in the photo would result in a modest contusion to the cheek.
There was no provision for zeroing the sights. The front sight was part of a one piece assembly; the rear had only elevation adjustment.
The bipod tends to flop around. Only when it is fully forward, as in the photo, is there any stability.
The best features of the CSRG was that they were available in quantity from 1916 on, and well trained automatic riflemen could get effective service from them.
Note that in the photo there are no pouches or other support equipment; the magazine is empty, and the gun not cocked.
Probably a posed training photo, with the actual type of gun being unimportant.
Of course, the SS did specialize in shooting people who couldn't shoot back.
Hate to mention it, but the SMLE was also selectively assembled, hand fitted, with serially numbered parts.