Interesting comment.. I have sold over 7,000 of my Devices and older folks with weak hands, Arthritis and women etc love it. I have sold many to people who have only one arm. Have you tried to load a Garand with one hand??? Most of the catches were made by converting GI Op Rod Catches, however I used up most of the surplus so I now make them from scratch and they work well....
They are very easy to make, just cut the mag release arm off, then drill a hole in the catch and insert a spring... I use a #22 drill bit for the hole.
Here is a photo of a converted GI op rod catch for reference. Anyone who needs assistance, please contact me.
http://m1thumbsaver.com/