Powder question imr vs h powders

[john 800]

Has anyone seen a case where a specific rifle shows a strong preference between h or imr powders? The ones I deal with are 4350,4831,4895 in 308w,270w and 7 rem mag.
I have loaded imr 4350 in 270w for a long time and I see people going crazy to find h4350 when imr 4350 is more available and I have to admit onceI see a good group with a powder I tend to fine tune from there rather than start over with another powder.
Could all these guys that are killing themseves tryingbto scrape up more h4350 just buy a jug of imr 4350 and load a bit different according to temps?

 

[bloc]

My .270 doesn't like IMR 4831, but loves the slightly slower H 4831.

 

[Ned Ludd]

Perhaps it is just my own inference, but it seems as though a comparison between IMR and Hodgdon powders having the same number implies there is supposed to be some similarity between the two powders. The example I can speak to directly is IMR4895 versus H4895. They are two very different animals. Their kernel sizes/shapes are different, their burn rates are different, their bulk densities are different. I use both both and IMO, a good analogy to comparing IMR4895 and H4895 would to attempt to compare Varget and N150. Varget and N150 certainly have significant overlap in terms of the cartridges/loads in which they are commonly used, but they are also completely different powders.

I cannot comment directly on whether the IMR/Hodgdon 4350 and 4831 series are more akin to one another. I also have no idea why the manufacturers used the same number in their powders. That is something I think can be very confusing to reloaders attempting to find suitable powders in the current drought, especially if they may only have used one of a "pair" of powders previously. Nonetheless, my experience tells me that each one should be treated as a completely new and different powder, until/unless reloading experience with each powder of a "pair" has been gained.

 

[Metal God]

The H's are generally more temperature stable the IMR . The one H I use H-4895 has a much shorter cut then the IMR-4895 resulting in better fill and metering .

 

[piie]

Perhaps it is just my own inference, but it seems as though a comparison between IMR and Hodgdon powders having the same number implies there is supposed to be some similarity between the two powders. The example I can speak to directly is IMR4895 versus H4895. They are two very different animals. Their kernel sizes/shapes are different, their burn rates are different, their bulk densities are different. I use both both and IMO, a good analogy to comparing IMR4895 and H4895 would to attempt to compare Varget and N150. Varget and N150 certainly have significant overlap in terms of the cartridges/loads in which they are commonly used, but they are also completely different powders.

I cannot comment directly on whether the IMR/Hodgdon 4350 and 4831 series are more akin to one another. I also have no idea why the manufacturers used the same number in their powders. That is something I think can be very confusing to reloaders attempting to find suitable powders in the current drought, especially if they may only have used one of a "pair" of powders previously. Nonetheless, my experience tells me that each one should be treated as a completely new and different powder, until/unless reloading experience with each powder of a "pair" has been gained.

Some powders, like 4350 are close, but as you rightly pointed out, some are NOT - if you don't KNOW - then don't assume - that is the safest approach, and there are plenty of other tools available to help if unsure. Use Hodgdon's reloading data website as one such tool - select your cartridge and then see if both the IMR AND H "version" is given as options, and even if it does, look at the powder weights to see how close they are.