Simply use another magazine or another CPT as a tool and load either side first. Then, turn the CPT over and load the second side. Simplicity itself. You can do it wearing gloves, even mittens. You do not have to worry which side first. CPT will load from either side. You don’t need any extra tools or gadgets, which are difficult to use in harsh or stressful conditions.
Using magazine and/or another CPT to slide the rounds into loading magazine.
Once done with the one side, turn the CPT around, preparing to Repeat
Same method, just the other side, all done.
Although, CPT is not limited to a certain ammo type, a simple query with your problem, will help us know, to provide the solution
CPT was born 2015.
I had been working in the Finnish Border Guard as Chief Instructor, Special Intervention Teams. Our specialist cadre worked with and tested a substantial range of firearms and vast quantities of ammunition whenever a new weapons system was being considered. It cannot be overstated that the quantities of small arms ammunition used / tested was significant.
This in turn required the loading of magazines, lots of magazines, hundreds, thousands, multiple thousands of magazines…