Having recently acquired Tikka T3 in 308, I noticed it's very easy to induce a kind of nosedive when operating the magazine by hand.
That is, keeping a loaded magazine in hand, using your finger or some tool, remove the rounds one by one (like the bolt does while shooting). On the last round, the follower seems to bind in the front and the last round seriously "nosedives". It doesn't matter whether you keep pressure on the back of the rounds (like the bolt does while actually using the rifle) or not. Also rounds significantly shorter than 71mm show this behaviour so IMHO it's the follower binding (not the bullet tips on the front of magazine). Tested with 3rd and two 5rd magazines, all brand new, same behaviour on all.
Since I haven't seen this behaviour while actually shooting or cycling dummy ammunition through the rifle, I'd like to avoid disassembling the magazine(s) to investigate/fix. But if it's a known problem I'd rather deal with it before it occurs in the field.
So, have you experienced nosedive on Tikka T3 M length magazines (243/308/etc.) while actually shooting the gun?
(all problems I could find with search were related to worn out mags and feed lips, and the problem was round not being picked up by bolt. So quite the opposite)