I seem to remember that some gun writer did some testing on bullets that had damaged tips. He deliberately filed off the tips at odd angles and they shot quite accurately. I would imagine BC would vary some.
I had to file off the tips on the 160 nosler partitions to have them fit in the magazine of a short action chambered for 284 win years ago. I called Nosler and said I wanted to make my own protected point bullets. They said as long as some lead was exposed past the jacket the bullets would expand properly. Shot my first bull elk with that bullet. It worked fine.
You could file off the soft lead tips leaving a small amount in front of the jacket. Look at a picture of the protected point partitions to get an idea. Naturally the BC will drop significantly but for distances under 300 yds no big deal.
30 Caliber 180 Grain
Partition Bullet
Part# 25396
Protected Point