I loaded s&w 500 mag 565 gr cast bullet with IMR-4227 30 grs and now I'm not sure how I came to this calculation and questioning myself if this is too hot load. Has anyone used this powder for heavy bullets like this? Need some suggestions before I go to range.

Disclaimer: I don't shoot the 500. Salt is indicated.

4227 is a good powder for the 1.6" supermags.
It is in between 110 and the slower N-120 and 1680 which are all used with success.

Hornady lists 33 grains as max with their 500 gr XTP.
Given its higher friction the pressure should be in the same ballpark.

If you were to give me the actual dimensions of the bullet, seating depth and cartridge OAL
I can do a more accurate simulation in QuickLOAD.

Raising the weight to 565 and lowering the load to 30 gr lowers the pressure by 9 KPSI so I think you are in good shape.

There are some loads at Handloads.com with heavy cast bullets and slightly faster powder that would
infer you are OK too

Normally I would load 10 rounds each at the starting load and 10 more going up a grain or 1.5 till you get signs of unhappiness
or your wrist gives out.

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Nemo

Thank you very much. Just to be safe I loaded 27gr. 28gr and 29gr. As you predicted they were all fine. Your technical knowledge is very valuable.
David

About 30 seconds after the .500 S&W and .460 S&W were introduced EVERYBODY decided "reduced loads" were more than adequate...when you view most reloading data it is centered around reduced loads...not TOP loads.
VERY few .500 S&W loads top 50K psi...a full 10K psi below design "average operating pressure." This is fine because the cartridge genuinely IS a beast, but it means MOST load data is intentionally mild.