IMR4227 and AR2205

[Obie73]

Here's something that perplexes me.
IMR4227 is said to be equivalent to AR2205. But when I look in the Hornady reloading manual and compare it to the NH manual it gives very different data for the .357 magnum (rifle) loads. Can someone explain why this would be? The Hornady manual lists much lighter loads for .357 mag with IMR4227.

[Harrisor44]

H4227 and AR2205 are the same powder. IMR4227 is not the same powder as AR2205 or H4227 although it has a similar burn rate but reloading data is not interchangeable. Would suggest you use the reloading data for AR2205 in the ADI Handloaders' Guide.

[bladeracer]

Here's something that perplexes me.
IMR4227 is said to be equivalent to AR2205. But when I look in the Hornady reloading manual and compare it to the NH manual it gives very different data for the .357 magnum (rifle) loads. Can someone explain why this would be? The Hornady manual lists much lighter loads for .357 mag with IMR4227.

Equivalent means the two powders are suited for use in similar situations, it does not mean you can interchange the load data.

[Obie73]

Thanks! Makes sense now.

[Wallaby stew]

Here's something that perplexes me.
IMR4227 is said to be equivalent to AR2205. But when I look in the Hornady reloading manual and compare it to the NH manual it gives very different data for the .357 magnum (rifle) loads. Can someone explain why this would be? The Hornady manual lists much lighter loads for .357 mag with IMR4227.

You could be excused for being confused about load data from different companies, I didn't say manufacturers because a lot of the powders available are made by ADI. I believe Hogdon never made powder just resold other brands. I was looking through a 1996 ADI handloaders guide and AR2205 isn't even listed for the .357.