Only reasonable way is to take MF hits in the ring. It doesn't work too well with small chips, I found gaining jamming worked much better taking attacks from big MF chips, but that might be a connection with having a lot of evade support skill or a lot of support MF skill.
Strike chips are great for earning jamming amongst a few players in the ring, if all carry and use strike, I tended to be giving the strikes than players offering them last few times I've been in the ring.
I was hoping for a jamming mob, that by its nature would be an MF hunted mob......MA built the opportunity for it, but appears they didn't take it further (sadly).
Rick