Need some guidance from the Gurus........

[Herb in Pa]

I've been experimenting with cast in the 221 Fireball using WW680, but alas, my supply is running low. I do have a goodly supply of 1680 but no starting load data........any way to extrapolate 680 vs 1680???

[Calamity Jake]

The jug of WC680 that i have says to use AA1680 data so I would think yours is about the same just reduce your 680 load 10% and work back to where you want to be with 1680

[MakeMineA10mm]

The jug of WC680 that i have says to use AA1680 data so I would think yours is about the same just reduce your 680 load 10% and work back to where you want to be with 1680

That's exactly what I'd do. I have two jugs of 680 left, so I'm hoping it will be awhile before I confront this.

If you're specifically shooting cast, I'd think 2400 may be a good choice for that application too.

[Rocky Raab]

It will come down to lot-lot differences, the two are so close. In tests I ran some time back, my bottle of 1680 was just a hair faster than my 680 in the hornet (with jacketed bullets). But any two other cans might be the reverse.

Reduce your normal load (not necessarily the book max, but YOUR load) by 5% with no other changes whatsoever and compare velocities. That will tell you quickly and safely whether the new powder is slower, the same or faster than your old lot.

[Herb in Pa]

Thanks Gentlemen................