IMR4350 vs H4350

[YATYAS]

I am getting into reloading my own ammunition. I heard the IMR powder is more temperature sensitive and the H is not. Anyone here have experience with these two powders? I have also heard that they are the same powder with a different package and label.

Go right to the Hodgdon web site and you can compare all powder data and load data.

[YATYAS]

Originally Posted by Shooter 2

Go right to the Hodgdon web site and you can compare all powder data and load data.

I am more interested in temperature effects. I see that the H4350 is temperature resistant and IMR is not. I am just wondering how much temperature can affect a load.

[Uncle Paul]

Yatyas you never said what your goal is reloading or what cartridge you will reload but unless you measure your groups with a quarter inch ruler or your closest target is 1000 yards or more you might be wasting time worrying about temp effect on a powder. When I started to reload metallic shells and would hear things like temp effect on shells I would try to track down the source of the info and most of the time I never could even with the internet. I trust the manufactures of the powders and they have a lot to lose by selling a powder with issues. Like it was said go to their website and look it up and if you have a question you can always ask them a specific question. One more thing never listen to anybody that says this and this powder are the same just a different label this thinking gets people hurt. Unless I see load data printed by bullet or powder maker I don’t load it.

[YATYAS]

Originally Posted by Uncle Paul

Yatyas you never said what your goal is reloading or what cartridge you will reload but unless you measure your groups with a quarter inch ruler or your closest target is 1000 yards or more you might be wasting time worrying about temp effect on a powder. When I started to reload metallic shells and would hear things like temp effect on shells I would try to track down the source of the info and most of the time I never could even with the internet. I trust the manufactures of the powders and they have a lot to lose by selling a powder with issues. Like it was said go to their website and look it up and if you have a question you can always ask them a specific question. One more thing never listen to anybody that says this and this powder are the same just a different label this thinking gets people hurt. Unless I see load data printed by bullet or powder maker I don?t load it.

Mostly hunting but would like to get into long range shooting (800+ yards) someday. I hunt in some extreme temperatures sometimes. I have hunted deer in 20 degrees to 80+ degrees. I have taken shots at deer out to over 400 yards. I have read that the effects of temperature can be near 1 fps for every degree of temperature change. So if I work up a load in 85 degree heat summer sun and shoot a deer in near freezing temperatures, how does that 50 fps difference effect my POI? I will of course figure that out but just wanted to generate some discussion and get some feed back. I look forward to testing this stuff out myself. I have found out a lot of info since I posted this and will try some different powders that are not so temperature sensitive (nothing is 100%) New IMR 4451 and 4955 should work with the rounds I am going to load. I read they are not has temperature resistant as the H4350 but should be easier to find.

This could also be a safety issue if a bullet is loaded to the max and sits in the sun for a while then shot in 100 degree heat. Could generate a pressure spike. There are a lot of things to consider which is why I find this interesting and I am looking forward to diving into it. If I didn't worry about getting the most out of a hand load then I would just by factory ammo.

[7 Mag]

I've used IMR 4350 for years hunting in extreme temperatures (Montana & Wyoming) and I've never had an issue or concern about the powder. I think elevation changes have more affect than temperature and besides todays rifles are a lot more accurate than most shooters abilities. Another powder I've had good luck with is RL-19 & RL-22, you'll have to experiment and see which one your rifle likes best, that's what I base it on.

[clawman]

Originally Posted by YATYAS

I am getting into reloading my own ammunition. I heard the IMR powder is more temperature sensitive and the H is not. Anyone here have experience with these two powders? I have also heard that they are the same powder with a different package and label.

H4350 is one of Hodgdons "extreme" powders meaning that is is not as temp sensitive as others.
I was walking with the owner of Bullbery Barrels out of Hurricane UT and he told me a story about an experience he had while testing loads. He had a good load worked up for a particular cartridge and laid a box of shells in the windshield. When he shot the first round the barrel blew up due to too much pressure. The shells were extra warm from laying in the windshield and created a pressure spike.
I have called Chris Hodgdon at Hodgdons powder and he has been very helpful with loading characteristics of their powders, if you want to debunk the myth that the two powders are the same.
Hodgdon owns IMR

[YATYAS]

I have established that the two are in fact different. The burn rates are very close but they are different. IMR lineup has its own temperature resistant powders that I may have try because the H4350 is impossible to find.

[clawman]

I am intrigued with what the military uses for snipers. We all think you have to work up your load for a specific rifle. The snipers are not sitting in a tent in the desert reloading custom loads. If the military can create a load for all of their sniper rifles why aren't there recipes for civilians to use in our rifles?

[YATYAS]

Originally Posted by clawman

I am intrigued with what the military uses for snipers. We all think you have to work up your load for a specific rifle. The snipers are not sitting in a tent in the desert reloading custom loads. If the military can create a load for all of their sniper rifles why aren't there recipes for civilians to use in our rifles?

Good questiom. Marine Corps M40 rifles are modified by Marine armorers. From my understanding, head space is a main factor in accuracy. I wonder if they mod the head space of each rifle to ensure the ammunition and chamber are a perfect fit.