I'll proudly drink my M1 Kool Aid. It's the best around.
All gas operated rifles are going to require port pressures, burn rates, and such to be within specific operating parameters.
We all know for example, what happened when the wrong type of powder was used in the M16 rifle.
The delayed roller lock system used by the HK G3 also depends on recoil impulses falling within certain parameters.
And the Kalashnikov, as much as I love it, isn't accurate enough to warrant reloading.
Now if that means never reloading for an M1/M14 or an AR, fine. But of course, those are the only semi-autos consistently accurate enough to deserve the attention.
Millions of reloaded rounds are fired through these platforms annually without incident. But precautions must be taken. This is true of everything you reload for, but more so with semi-autos--all of which are going to be more susceptible to slight differences in peak and port pressures, burn rates, and cleanliness, as well as external dimensions, than the average manually operated rifle. If these are measures you are unwilling or unable to take, the most certainly you shouldn't reload for your semi-auto. Being an amateur reloader myself, I have already accepted that I need much more practice loading before I am willing to try my hand loading for my M1A. I love that rifle too much, to say nothing of my hands and face, so the associated risks aren't worth it for me. Keeping the rifle in one piece is worth a couple extra cents a round in my case.