IMR 4198 vs H4198

[Mikee Loxxer]

I am in the process of loading some 7.5 X 54 MAS cartridges. I am pushing a 130 grain jacketed bullet with 30.5 grains of IMR 4198. In reviewing the loading data in the Lee reloading manual I realized the recipe called for H4198 instead of IMR 4198. What is the difference between the two? Should I not use the IMR 4198?

 

[Jim Watson]

They are different powders of similar burn rate and unfortunately similar designation manufactured half a world apart. IMR comes from Canada, H from Australia.

Are you at the maximum load? If not, I would not worry about it.

Bear in mind that the Lee manual just reprints powder company data; Hodgdon in this case.

 

[Mikee Loxxer]

Staring grains for H4198 with this bullet is 29 and the do not exceed is 33. I am using 30.5 grains of IMR 4198. Do you think that is close enough to be safe?

 

[Jim Watson]

Cross-checking some different manuals I see that is in the load range for .30-40 Krag and .300 Savage and I would consider that acceptable for a 7.5 froggie.

But it is best to read the data closely enough to use the right powder.