WE G19 Mag for TM
 

I know the WE mag has a stronger valve spring and the solution is a heavier hammer spring. I was wondering if the mag itself can be modded? Different valve/spring?

it should be able to be loosened off a small amount to the point where it should be able to be used. (i did the same thing with we g17/18 mags for a tm gun and vice versa) it takes some finessing to get it right and you will need a chrono on hand to test, but it is doable as long as the mag actually fits the gun and the dimensions allow the hammer to strike properly