Thanks, DZ and MH. That picture of the sectioned bullets is worth a 1000 words. Removes all doubt from my mind.
I understand the BT's above .308 diameter are also of a heavy jacket design. Mule Deer says the jackets comprise over 50% of the bullet weight, so one always gets at least that much retained weight. Kinda looks like these particular bullets are similar to that. Funny Nosler wouldn't tell us about this.
I have a buddy who is a big Nosler fan. He really likes the old Solid Base bullets. He currently uses the Partition if he can't find/use the Solid Base bullets. He doesn't like the BT's because they are too fragile. I'm going to tell him to look up these posts. He may well like this bullet.
He tells me Nosler told him they have redesigned the BT eight times. And, according to him, they still don't have it right, like the older Solid Base bullets.
I'm looking for an in between 120 gr. bullet for my .280. The dang Barnes people have changed the ogive on their X bullet again. And, I discovered, a simple primer change opened my groups alot. From .5 or less to 1.75 MOA. I'm about ready to switch to the Hornaday Interbonds for the .280 and the .308. For now, I'll fool with the X. The new ogive may be more forgiving than the fancy Secant Ogive of the older XBT design. But, if it doesn't work out well, the 120 gr. BT's may well get my attention. Or i'll just use them as all around loads. E