Dropping even an OEM follower rod down the primer magazine can set off primers, but the longer the drop and the heavier the rod, the more likely you will have an incident. i.e. if there is only a few primers left in the primer magazine and you let the follower rod free fall, you are likely to experience some ringing ears or worse.
As I mentioned earlier, the principal reason for the nylon or fiber end is not to prevent primer explosions, but to prevent damage to the primer slide.
There really is no reason to add extra weight to a follower rod. The OEM rod works fine, and if you are having problems there is something else wrong. It might be a bent primer follower, a dirty primer magazine, a small burr on the end of the primer magazine, or something with the primer system that is out of adjustment. Better to fix the problem than compensate for it with a heavier follower rod.
New primer follower rods are only $15.