45/70 loading info needed

[DECKAPE]

i bought  some meister cast lead bullets......300 gr. rnfp....im  in need of some loading data using imr-4198........in one book i have they are talking about using a filler wad ........what is all about???  ive been loading for a long time and never heard of this.........

[Leftoverdj]

Some folks use fillers or filler wads to keep the powder charge back against the primer. There are risks involved and reports of ringed barrels so I don't do it if I can get good accuracy by other means.  If you do use a wad, it must be solidly against the base of the bullet.

I'd try 13 grains of Unique under those 300 grain bullets long before I'd try IMR 4198.  I note that Lyman shows dacron filler with IMR 4198 and assume that is the manual you checked.  They cut theirs from quilting batting. I use loose. One grain is about the right amount and it should be fluffed to fill the powder space.

[quickdtoo]

Fillers may be recommended with some load data for large capacity cases with low powder charges, but I haven't seen any powder mfr recommend fillers, in fact, the load data that I use from Hodgdon and Accurate Arms specifically state NOT to use fillers. Fillers keep the powder near the rear of the case in large cases like the 45-70, a lighter charge can put the  powder entirely away from the primer flash hole and cause erratic ignition, accuracy and pressures. My recommendation is to used published data and if fillers are called for, by all means.

Tim