Assuming you are referring to the rimfire hollow pointer tool availabe from E Arthur Brown Company, they work like a charm. I can't recall who manufactures the tool but they are well made and cut a very uniform cavity as to depth and diameter. I use mine to expand the cavity of various types of HP rimfire ammo. Works great with CCI Stinger with visably more explosive impact on ground squirrels and the like. On Stingers it reduces the standard bullet weight by .7 grns from 32 to 31.3 grns. I also use it on Mini Mag HPs with good results.
As to any effect on accuracy, my results have been same same or slightly improved accuracy when expanding existing HPs. Haven't used it to hollow out any solid point stuff but it would no doubt do the job. Good luck I'm sure you'll find the money spent for your new toy well spent...
