Loaded some 180 Nosler E-tips in the 300 wsm using Hodgdon Superpeformance.

63-----2864
64-----2855
65-----2945
66-----2974, 2976
66.5---3001, 2987
67-----3019, 3001

The initial drop in velocity from 63 to 64 and the jump of 90 fps from 64 to 65 tells me I started at max. Only adding 30 fps then 25 fps at 66 and 66.5 and no increase at 67 confirms this.

63 may be the actual max for this combination but I have to try 60-63 to see for sure but I am sure thats what it will show.

BTW the cases all looked the same. No flattened primers and no sticky extractions.

24" barreled Winchester Mod 70 Camo Ultimate Shadow Stainless.

I chronographed some loads today with my 300WSM using Re17 and 180gr Accubonds and the average for three rounds was 3008. I am well within the load data that is on the Alliant website. I have run the velocity with 180gr Accubonds up to 3150 and still a grain under the max on the Alliant data.
I was shooting a Win 70 Featherweight with 24" barrel.

Some good numbers there! I'm itching to try RL17 in my 300wsm myself. IMR4007SSC has worked wel for me.

Anyone else using the Superperformance in 300WSM??

I do not have a 300 WSM, but have tried it in my 25 WSSM.

Performance was OK, but not "super".

What really bothered me was the barrel full of soot after every shot. It is the dirtiest rifle powder I have ever worked with.

Have you noticed that?