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A 10 round short magazine has a red follower with black load assist button.
A 10 round long magazine has a blue follower with no load assist button. It also has a pin that prevents the follower from going all the way down.

You can knock out the pin on a 10 round long and then put a load assist button of your own making in. But the magazine will be illegal in some states.

So, while 'physically impossible' isn't totally correct, it's not possible without hacking the magazine. Once you take the pin out, it's no longer a 10 round long, it's a 25 round long with a blue follower, which is illegal in some states.

Use a golf tee. Works better than the load assist and does not require modification of the magazine.