Get a collet puller, no breakage nor frustration.
This, slow but sure and a lot safer. Also JB has written that inertia pullers can loosen the core and jacket alignment and hurt accuracy. I have observed this but didn't know the cause until JB wrote of it.
I blew a cap with a hammer puller when I was 12 yrs. old. Fortunately no powder in the case (the reason I was pulling) and I had glasses on too. That one eventually shattered and good riddance to it.