IMR/H 4350

[eroyd]

I understand IMR and H4350 are a little different but it generally seems they are used for the same type loads. When a manual gives a load for IMR4350 but not the Hodgon what should I use? I happen to have a fair bit of H4350.

The particular load I'm working on right now is 257 Roberts Ackley improved in 100, 117 bulet weights.

[KN]

Go to the Hogdon web site and look at their tables. If it's suitable for your load it will probably be listed.  KN

[ricciardelli]

Burn rates, faster to slower:
110. AA-4350
111. IMR-4350
112. H-4350
 
That being said, never substitute one powder for another , no matter how close the burn rate.

If your book doesn't list H-4350, then buy one that does, or go to:

http://stevespages.com/257_9.html

For the .257 Improved the following were the loading ranges I found useful with a 115 grain bullet:
AA-4350 From 40.5 grains to 44.5 grains,  Remington 9-1/2 Primer
IMR-4350 From 41.5 grains to 46.0 grains,  Remington 9-1/2 Primer
H-4350 From 43.0 grains to 47.0 grains,  Remington 9-1/2 Primer

[eroyd]

Thanks for the site recommendation. I've checked out a few and have come to realize that trying to make predictions is useless. It appears that (for example) max. load of the H-4350 might be more than IMR-4350 with one bullet weight but that can totally flip using different bullet. It's also pretty clear that different manuals list different maximums, I guess depending on the test rifles they use. Some differences are pretty dramatic. Best to start at  the bottom and work up watching for signs of pressure. (as usual)