My Vanguard likes 81.5 grains of H-4831, 80 grains of RL-19, and 84 grains of RL-26 with the tried and true 180 gn Hornady Interlock. My Mark V likes the same loads. How’s that for lucky? The Mk V also likes the 178gn ELD-X with 84 grains of RL-26.
I tried W-780 but the measured velocities were all over the place. Since that powder was dropped by Hodgdon I wouldn’t explore it as a viable option.
All loads were with Winchester large rifle primers and either Remington or Weatherby cases.

The only crimping I do is for my 30-30. I don't even crimp the .460 Wby mag.

Folks as noted in the title I have a German 300wtb mag mark v deluxe that hasn’t been fired with the original box.  I might have the factory target too.  Anyone care to venture a guess on value?  I think it’s a 24 inch barrel, it hasn’t been out of the sock and safe in 6 years so working off memory.  Gun is flawless.

A little trivia Barnes was not the only company  to have relief cuts or relief grooves in their bullets. Barnes came out with the  all copper X bullets no relief cuts  it was noted not all rifles like them,  then came the Barnes XLC bullets a coated bullet no relief cuts, Then the Barnes TSX followed by the TTSX both have relief cuts,  my understanding  machine made bullets with machine cuts,   reasons to to reduce pressures by reduce bearing surface and reducing copper fouling.   I know Barnes gives recommendations as to seating depths  and these should probably be followed they have enough time in the seat with them to understand what's going on. My original TSX bullets when they first came out would place an amended load data  statement inside each box of bullets,  They haven't done that for quite a few years.  The relief cuts on current 180 grain TTSX and my seating depth of 3.560 means not all relief cuts are inside the case the top relief cut on the 300 WBY and the TTSX -BT-180 grain is right at the top edge of the case totally outside the case when seated.  It's not a problem it's where the cuts were positioned.  As long as the COAL fits in the magazine freely and cycles correctly and the bullet is not jammed in the rifling you should be OK.  There are 2 ways you can increase pressures from seating bullets at different coals ,  by seating bullets too long OR too short i.e. compressing the powder column or jamming the rifling.

buffby makes very good points.  I don't know for sure how the Trophy Bonded Tip bullets are actually  made since they are 2 different metals I have a good idea but that's about it.  The bullet has a rear copper shank, front section lead under copper with a skived front with a polymer tip, followed by nickel plating,  with relief cut/grooves and cannelure.   Just my opinion I really don't think seating depth is a big deal so long as we follow a few rules,   you don't jam the rifling when seating the bullet for length,  (yes I know some bench shooters do it),   I wouldn't seat the bullets too deep either,  both  ways you go can increase pressures,   go with what the bullet makers recommends for seating depths to start with and work seating depths in and out as accuracy improves or degrades.  Use a chronograph and watch for any velocity spikes and pressure signs.
 Start with a lite powder charge (reloading 101) and work up. The original TBBC's (Trophy bonded bear claw) are very good bullets I don't know if the Trophy bonded tip bullets is a big  improvement or not ? maybe ?  Just don't go too overboard on excessive seating depths to start with.

Looks like it sold today ($2,675).

Crazy!!