Light loads with IMR4198

[snaketail]

I'm working up some light loads for .30-30 with 125g and 135g cast boolits. They work OK with 8g of Unique, but I have more IMR4198 that Unique. Hogdon's guide says 22g of IMR 4198 will give me about 2000fps. I'm looking for something slower, around 1300/1400fps. Is IMR 4198 a good powder for lighter loads?

[Outpost75]

You can use .32-40 Winchester data for the same weight bullet as a guide. Lyman Cast Bullet Handbook, 4th Edition, p.174 shows 16 grs. of IMR4198 with 170- grain bullet for 1397fps, 14,100 cup. Pressure and velocity in the .30-30 will be somewhat higher, but this will be a safe and satisfactory load.

[BCRider]

The Hodgdon Cowboy Loading manual has information for lower velocity use. In that publication it shows .30-30 being loaded for a 160gn cast bullet for 15gns of 4198 to give 1400'ish fps and up to 17gns to give 1600'ish fps. It doesn't show any less than that.

The manual does show various loadings in other calibers that show 4198 being used in the 14K CUP pressure range and one which is 13.3K CUP. So this suggests that you'd be OK with reducing the loads to 15gns and slightly less to where you're running down as low as 13.3K CUP.

But even at 13.3'ish CUP I suspect that the lighter bullets are still going to be screaming along compared to the velocities you're after.

Because the peak pressure occurs early you could experiment with loading some filler such as cream of wheat over the powder and using a little tuft of Dacron filler to hold it all in place firmly enough that it won't separate. Or perhaps put in separator discs of printer paper, craft felt or something similar. The idea being that the CoW would pack the casing a little and let the pressure rise into the 14K to 15K region so you get a full and clean burn from the lighter charge.
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[snaketail]

Thanks -I didn't know Hogdon had a Cowboy Loading section. This is great help.

M