No. They are not necessary, generally speaking, but there is no problem using them. If charging with spherical (ball) powder, magnum primers may be indicated. If hunting in extremely cold weather, magnum primers may be indicated. Otherwise, they are not necessary, though they create no problem. All this assumes you work up your load according to sound and safe hand loading practise.
I've used them in my '06 and 180 BT's/AB's. I don't remember why I tried it but it worked well for me in terms of accuracy and velocity.
I do wonder though if the mag primers erode the throat of a rifle faster than others, my '06 throat went bad sooner than I had expected and I have wondered if it could have been a result of the 215M primers. I have no way of knowing but that was just a thought that was on my mind.
Awhile back i had a savage 30-06 that gave me grey hair tuning. In the end i chaned the brass from new production Win and tried some 215 fed. Went to a consistent half in gun. Never in my life have i struggled tuning like that. I remember the load and the gun had been long gone. 62 grs h4831 fed brass and 215 primers 168 matchkings.
I had the same trouble when I had my custom 25-06 built. I knew that it was capable of shooting better than 3/4" @ 100. Switched to CCI 250 mag primers and BUG HOLES.
I have used the Fed 215 Mag primers in my .30-06 for cold weather. I did not even have to adjust my worked up to, the IMR 4350 powder charge, because there were no pressure signs at all. This was for hunting in Wyoming when it was about -10*F in the morning about 10 years ago.
I had the same results with a 6mm-06 i have. I went from a decent group to a great group just by switching from a 210gm to a 215gm. my load was 56gr of H1000 and 105gr berger hunting VLD. i was getting very sooted necks and the hotter primer fixed this.