With both parents shot and killed by all the bullets being capable of being loaded into the anshulz rifle, Sheila did not have to rush about reloading the gun, because her main adversaries (mum and dad) were already dead, providing no risk to her of being attacked by them, all that was left by that stage, were three human hearts beating, Sheila's, and the two children...
Ralph and June are dead (at this stage), 11 rounds have been discharged, the weapon is empty, Neither Sheila herself, or the two children had yet been shot or wounded...
Sheila had all the time in the world to reload, if she needed too, or use a separate gun that had, or needed to be reloaded, with 14 additional bullets...
This is where the 14 bullet cases (MDF/100), which are currently held in storage at Huntingdon Lab', came into play...