The mags would take a lot of modification to fit, the m16 mags are the same thickness front and rear whereas the mini 14 the front is narrower than the rear. Modifying the gun could be expensive because if you can't get it to work, you have to buy replacement parts or a new receiver if that part had to be modified. Buy a m16 mag and compare it to your mini14 mag , you may be able to make it work. About 20 years ago there was a plastic magazine that was supposed to work in both mini14 and m16, but they don't seem to be around now so I don't know if they didn't work or there was no market. I think they tried to make a mag that would work in a mini 14 and then also work in a m16, but m16 mags in the U.S. are so cheap, why go that route.