As long as it can only handle 10 rounds when it is done, you are good.
A Glock mag, good luck getting the baseplate off without the right tool, so probably OK.
If you need a tool to remove whatever is capping the mag it's considered permanent. Shotguns are a diff. story tho (reason is obvious).
My glock mags are permanently adapted by small metal plates JB welded to the back of the inside of the mag...unalterable
I was thinking of the 32 round body mags I had, the baseplate is secured by two protrusions that snap into the sides of the magazine body where you have to squeeze the very bottom of the mag body enough to slide the baseplate off. I couldn't do it by hand.I think any punch does the trick.
My glock mags are permanently adapted by small metal plates JB welded to the back of the inside of the mag...unalterable
Little more than that I think. Has to be done in some form of a more permanent way.
I think sticking a dowel of a certain size in the mag for instance, may not be enough. At least not for many other types of magazines. A Glock mag, good luck getting the baseplate off without the right tool, so probably OK.
I was thinking of the 32 round body mags I had, the baseplate is secured by two protrusions that snap into the sides of the magazine body where you have to squeeze the very bottom of the mag body enough to slide the baseplate off. I couldn't do it by hand.