So, I have some cases of .243 WSSM. I usually load 5 rounds at each powder weight level and 5 levels in my initial trials for maximum load levels.

I’m loading a 100 gr Grand Slam bullet. Can anyone verify the load data is in the right range?
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Perhaps I have one too many powders. Which one of the following would you drop? If you could add one… what would it be?<O:p</O:p
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Any information appreciated – even if it is “…what the heck are you thinking???”!!!


.243 WSSM
Bullet COL Primer
100 gr Speer Grand Slam 2.300" Win LP

Powder Load Weights (grains) Expected Velocity (fps)
IMR 4350 40.0 2898 52,600 PSI
40.9 2950
41.8 3001
42.6 3053
43.5C 3104 62,600 PSI

IMR 4831 40.5 2897 53,200 PSI
41.4
42.4
43.3
44.2 3098 62,800 PSI

Varget 34.0 2829 53,600 PSI
34.5
35.0
35.5
36.0
36.6 2981 62,100 PSI

So, I broke down and paid the $25 for the Speer Reloading Manual #14. I am glad I double-checked. The data they show for IMR4350 has a Maximum charge well below the minimum I found and posted above!!!

Anyone who has considered using this data should also buy the Speer Manual. It lists different powders than above. Ramshot Magnum, RL-22, Viht. N560, RL-19, etc.

The speeds show only a slight increase over the oldler, slower Win .243 but always with a more efficient use of powder (about 10% better with the newer, faster .243 WSSM).

It seems strange that Speer states a 100 grain Grand Slam bullet pushed over 3,000 fps would be good up to "Medium Sized Deer". I guess I'm used to reading Barnes Bullet data. Seems to me the Grand Slam's construction for terminal ballistics would make it sufficient to kill an elk. Perhaps that comes down to distance, angle of the shot and of course shot placement. Broadside inside of 200 yards and I wouldn't hesitate to take out a bull elk with the Grand Slam in the .243 WSSM.

Then again I carry at 300 WSM pushing a 180 grain Barnes Triple Shock for Elk, and the .243 WSSM would be only a backup in case I forget a part or ammo for the 300.

At any rate, I suggest not using the data from the original post. I'll delete the entire thread in a bit after allowing folks to read this notice.

has anybody shoot a 115 VLD berger in .243 wssm?