IMR 4350 to H4350 in 30-06

morgaj1

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I have a Tikka 30-06 that is the most accurate rifle I own. It is not picky at all and I have loaded 150-180gr bullets with several powders with success. My favorite load is 165 AccuBond over 56gr IMR4350. I use this for everything from whitetail to hogs to rams and would use it on elk if I can ever draw a tag. Now that I have a chronograph, I have noticed temperature sensitivity with IMR 4350. Problem is, I live in AL and do our load development and practicing during the off season where temperatures are frequently in the 90's. Our hunting season temperatures vary from the 50's down to the teens. I bought some H4350 in hopes of more temperature stability. I will obviously start low and work my way up. What has been your experience in the following:

1. Accuracy when switching between IMR 4350 and H4350?
2. Corresponding loads in IMR 4350 vs H4350? Consulting my reloading manuals, it appears that there is typically 0.5gr increase for H4350 over the same velocity for IMR 4350. For example, it appears that 46gr IMR 4350 with 165gr bullet would be roughly equivalent to 46.5gr H4350 for the same velocity.
3. Thoughts on temperature sensitivity for IMR 4350 vs H4350?
 

Mark @ Exo

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I get a slight accuracy edge with H over I in my 30-06 Tikka. Temp stability is definitely improved with H. And, yes, I also run a slightly higher charge with H.

I am running 56g with 166 Hammer Hunters. I don't hit pressure signs until I exceed 57.

First three down the pipe yesterday...
 

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CO_Guy

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I also see a range of roughly 0.3 to 1.0gn difference between the two for 30-06.

I use both for CO hunting where the temps vary from hot to very cold, for a wide range of calibers. Some of my rifles prefer the IMR4350 and some prefer the H4350. I don't see any change in performance when I dial in an IMR load, with temp variation.
 

RevJim

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I've used alot of IMR 4350, I grew up in East, Texas, and overall, I never saw any change in my zero from hot to cold. However, when I moved to Utah I went to the Extreme Powders years ago. However, I still use many older/newer powders too and IF ( a big if) my rifle changes zero from any temp swing, I drop that powder. I'm way too OCD about Reliability, ha. I've found that the temp issues have alot to do with the cartridge/powder/bullet combo. For example, you can read of R17 being sensitive, but in my 300WSM/168 TTSX it shoots as well at 90 deg as it does at 40 deg. Only way to know for sure, is test it yourself. I load all year long, because I love it, so I keep notes. ( I have to add, since I've never been overrun by any game animal, could it be that maybe they know my guns always go "bang"?, hmmm? :)
 

Stammster

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I wouldn’t worry about temp stability unless you are shooting long range and/or at max load.

With that being said, the new IMR4451 Enduron powder has the same approx burn rate as H4350, and supposed to be just as temp stable. Unless you’re in love with the IMR4350, I would try to the H4350 and IMR4451.

Both IMR4350 and H4350 are supposed to be within 0.5 grains of one another. This is generally the case, but my currents lots are such that my IMR4350 is a slow lot and my H4350 is very hot. In fact I am 1.5 grains under max (based on the conservative Nosler 8 book) in my 30-06 and still seeing excessively high velocity and pressure signs with my current lot H4350 at 70F.
 
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morgaj1

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I wouldn’t worry about temp stability unless you are shooting long range and/or at max load.

With that being said, the new IMR4451 Enduron powder has the same approx burn rate as H4350, and supposed to be just as temp stable. Unless you’re in love with the IMR4350, I would try to the H4350 and IMR4451.

Both IMR4350 and H4350 are supposed to be within 0.5 grains of one another. This is generally the case, but my currents lots are such that my IMR4350 is a slow lot and my H4350 is very hot. In fact I am 1.5 grains under the conservative Nosler 8 book max in my 30-06 and still seeing pressure with my current lot H4350.
Wow, you did get a hot lot. The funny thing is, I have used IMR4350 for many years for multiple cartridges and never thought about temp sensitivity. Then, I get a chrono and I see the objective difference. My OCD won't rest until I get a more temp stable load!
 

JMW67

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I have a Tikka 30-06 that is the most accurate rifle I own. It is not picky at all and I have loaded 150-180gr bullets with several powders with success. My favorite load is 165 AccuBond over 56gr IMR4350. I use this for everything from whitetail to hogs to rams and would use it on elk if I can ever draw a tag. Now that I have a chronograph, I have noticed temperature sensitivity with IMR 4350. Problem is, I live in AL and do our load development and practicing during the off season where temperatures are frequently in the 90's. Our hunting season temperatures vary from the 50's down to the teens. I bought some H4350 in hopes of more temperature stability. I will obviously start low and work my way up. What has been your experience in the following:

1. Accuracy when switching between IMR 4350 and H4350?
2. Corresponding loads in IMR 4350 vs H4350? Consulting my reloading manuals, it appears that there is typically 0.5gr increase for H4350 over the same velocity for IMR 4350. For example, it appears that 46gr IMR 4350 with 165gr bullet would be roughly equivalent to 46.5gr H4350 for the same velocity.
3. Thoughts on temperature sensitivity for IMR 4350 vs H4350?
Years ago I also used imr 4350 never any issues but went to h 4350 picked up a little speed and better accuracy I will be trying rl 16 next should be a great powder for the 30-06 with 150-168 bullets
 

Savage 12BVSS

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I guess as an IMR fan, my OCD has been treated with regular infusions of delicious pronghorn and elk! :p
I've used both in same gun and found the H4350 had to be about 1/2 grain lighter than IMR4350. Accuracy is too close to call and the H4350 is more temp stable. I use either one I can get in these powder shortage times.
 

Frank in the Laurels

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I've NEVER found any cartridge or rifle in any caliber that didn't shoot H-4350 more accurately...and I use it in a ton of cartridges...for whatever reason it's always better in the accuracy department. The best if you could only have one powder by far...NOW IF YOU COULD ONLY BUY IT...
 

morgaj1

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I've NEVER found any cartridge or rifle in any caliber that didn't shoot H-4350 more accurately...and I use it in a ton of cartridges...for whatever reason it's always better in the accuracy department. The best if you could only have one powder by far...NOW IF YOU COULD ONLY BUY IT...
I couldn't find it locally, but Midsouth Shooter Supply has it in stock.
 

montana west

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stryker montana
I believe that imr 4350 once was the go too powder however now it is made in CANADA and not the same as the old imr 4350 of years ago .. H 4350 made in Australia is very good powder and I do like it better.. loading in the 416 remington mag. 90 grains it will give me 2430 fps with a 400 grain bulle whis is in excess of 5000 fpe.. and pressure is lower that the IMR . thus it is a no brainer.. I see no use for the IMR as hodgdon owns both..
 

nicholasjohn

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I've used alot of IMR 4350, I grew up in East, Texas, and overall, I never saw any change in my zero from hot to cold. However, when I moved to Utah I went to the Extreme Powders years ago. However, I still use many older/newer powders too and IF ( a big if) my rifle changes zero from any temp swing, I drop that powder. I'm way too OCD about Reliability, ha. I've found that the temp issues have alot to do with the cartridge/powder/bullet combo. For example, you can read of R17 being sensitive, but in my 300WSM/168 TTSX it shoots as well at 90 deg as it does at 40 deg. Only way to know for sure, is test it yourself. I load all year long, because I love it, so I keep notes. ( I have to add, since I've never been overrun by any game animal, could it be that maybe they know my guns always go "bang"?, hmmm? :)
I've read that the temperature sensitivity can vary with different bullet weights, and from one cartridge to another. I've not seen this written anywhere, but I think differences in expansion ratios are probably a factor in this variability. There is probably a perfect combination of bore diameter, case capacity and bullet weight for each powder, but finding this "balance point" would be darn near impossible.

I saw a study that my buddy sent me showing the relative sensitivity of various powders, and H-4831 had the lowest variability among the powders in the test. ( H-4350 and Varget were pretty close behind it.) All the Hodgdon Extreme powders tested well, and I remember that IMR 4350 also did pretty well. My buddy was working with RL-22 at the time, and it did not test favorably. Ball powders showed a lot of variability as well.

With your relocation to Utah you will be shooting at different elevations as well as varying temperatures. This will cause a lot of trajectory changes for you as well. You mentioned that you consider yourself to be a bit "OCD," so you have probably also considered that as a big factor in the changing zero of your rifles. I wouldn't really call that obsessive - you're just a detail-oriented shooter. I think that's pretty much where we all find ourselves.
 

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