Hmm, learn something new every day.
Had never heard of such a hybrid before.
As above, 7mm FMJ is going to be thin on the ground.
Might could find a spizter lead mould, but 7mm in non-hunting loads is probably a unicorn.
Now, 6.95 (e.g. 7mauser) will have FMJ. But, .284" rounds, not so much.
Unless you could find some .276pedersen (7x51) rounds and pull the projos. But, tha would be a bit like buying a $10 round to build a $5 one.
Ok, further research turns up that Radway Green was using a ±140 FMJ at about 2400fps.
So, not quite as energetic as the .280 ross (7.3x66mm) which was 140 FMJ at 2900fps.