Found the 100 grain Nosler Partitions had marginal stability in my 1899EG with a 1 in 14 inch twist. Groups tightened when I shortened them by cutting the bullet noses back to the front edge of the jacket.

They work fine in my later Model 99A (the model with a top safe and a 1 in 10 inch twist).

I have an old Handloader’s Digest that shows that, back in the day, Nosler made a rounder nosed .257” 100 grain Partition for the .250/3000.