Anyone know if a 125 grain Nosler Ballistic Tip leaving at 3900 fps would be toughenoughat close range for deer?

I would certainly hope so. That is enough for an arrow moving at 200 fps. It may not deliver as much energy as a heavier bullet but I'm sure it's plenty with proper shot placement. Especially at closer ranges.

What caliber are we talking about out of curiousity?

Paul

Lazzeroni 7.82 Warbird (.308)

I mean would it hold together at this velocity? Gun shoots very tight groups with this bullet, would love to use it for deer, but not if it would fail at close range.

I don't think it will,thats a light for caliber bullet more intended for varmits(also moving very,very fast),it might work if you avoid dead on shoulder contact or bone.But IMHO you will have a bullet break-up.
BBJ

That bullet explodes like a bomb at 3550, so I can only imagine it will get worse at 3900. Great "terminate with extreme prejudice" varmint load - but not good for deer. I'm not sure I would want to use any of the ballistic tip bullets for a .30 caliber this fast. Go for a Barnes TSX, Partition, or one of the bonded bullets.

I wouldnt chance it for deer...I had trouble with em at 2900. With a gun like that..spend the money and get a decent bullet.

What bullet would you recomend? I'm partial to accurate bullets just in case a longer shot presented itself.

It is hard to beat a Barnes TSX on these .30 Super Magnums. I have used the 150 grain Barnes X (NP3 coated) in a .30-378 Weatherby with good results. Fast, flat, good penetration, not a lot of tissue damage.

I think you should try it and then report back in the fall of its results. Try to take some photos and report back penetration.