As much as I can remember, black tip in .30 cal. was steel, hardened steel or tungsten core and/or considered an AP round. They were not known for their superior accuracy, only for their punching through more dense material, such as steel, of a certain thickness at a given distance. They are not allowed at a metallic silhouette match and are impractical for paper punching due to their difficulty in obtaining and so/so degree of accuracy.
Not sure what you would want/need them for and since I am an old 'across the course' shooter and striving for repetitiveness of accuracy over varying distances and conditions, it would not be on my short, or for that matter long list of desirable projectiles to shoot.
If you are seeking accuracy in a .308 and/or 30.06 round, I may be able to make a suggestion or two regarding what bullet I found to be the most competitive.