Hello darwinmauser

200gms Beeswax
100gms White Petroleum Jelly (Vaseline)
75gms “Lee Liquid Alox”

This brew should end-up sort of a gooey texture, but not tacky. Not hard, but sort of in-between crayon and grease. A bit like ready to use putty.

Add a little Beeswax to stiffen the mix, or a little Vaseline to soften.

Not sure how it will work in the smaller 6.5 bore and at the speeds you are aiming at, but for a home made brew this one worked well in my old Ruger No.1 375 H&H with a 265 grain GC at just under 2000 fps, acceptable accuracy and minimal leading with straight wheel weight projectiles.

Another good one I have used is 50% Beeswax, 50% Molybdenum disulfide/graphite grease. It also should be sort of gooey. Might have to juggle with the quantities a bit to get the right consistancy. Up there in NT you might need to add a little more Beeswax.

Experiment a bit and see how it goes.

Good luck with it.

Best
ALEX