Tell me what amount of H4350, I should use in a 260 with a barnes 127 gr. LRX, or a lapua scenar 123?
Yes.
QL says 44.2gr behind the Lapua for ~2900 in a 22" tube and at 60K.
Even the latest update of QL doesn't list the LRX.
I asked is a long time ago, maybe it's been added now?
It's easy enough to add a bullet assuming you have some and can perform some measurements. In fact, I always measure my bullets and update QuickLOAD's database with my own measurements. QuickLOAD's bullet DB doesn't always jive with reality...
I asked is a long time ago, maybe it's been added now?
The new version 3.8 has the Barnes 127 LRX listed for calculations.