IMR4227 for 357 mag - confusing loading data

Winzer

Winzer

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I am using CamPro 158gr FCP TC.

The Hornady Handbook gives a range of 12.4-14.5gr for 158gr FP or HP XTP bullets with IMR4227.

CamPro's website does not list the IMR4227 but lists the H4227 (and my understanding is that they are in fact the same powder).

CamPro gives a range of 14.5-16gr (so basically their minimum is the max listed in Hornady Handbook)


So my question is, do I either assume that:

A) 158gr FP/HP XTP bullets are equivalent to CamPro's FCP TC (the book does not list IMR4227 for 158gr LRN, so not all 158gr are created equal?)
or
B) IMR4227 and H4227 are the same and one of them has their data wrong (and my only option is to load exactly 14.5gr)
 
They are both right because they have different setups when testing for load data. I have used imr4227 in the past but don't have access to my notes currently. Regardless of that i would start at 12.5gr and work up until you have a load your happy with or the pressure gets to high.

If there is enough info for what ever cartridge i would use cast loads for plated but if there is only jacketed info available i just use that for the same weight bullet.
 
IMR4227 is not the same as H4227. It is faster. Use at least a half grain less with IMR.

And you should not compare a plated bullet to a jacketed one. They are different. I assume CamPro is plated.

If it is plated, you can use more powder than with the XTP. With IMR you can go to 15.0 with plated. But I would load a few at 14.0 and 14.5, first, to see how your gun handles them.
 
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