IMR 4350 and H4350, What's the difference?

[CANNONMAN]

I just got my Redding dies yesterday and am just about ready to start reloading for my 6.5 Creedmoor. I ended up getting, Wife and a friend, both IMR 4350 and H4350. What's the difference? More specifically, The 6.5 Creedmoor, .308, .223 and perhaps a 7 Ultra mag would be where I am interested in using these. The store where these were purchased will return powder if the seal is not broken. Unless you folks think otherwise, I was considering returning the IMR 4350 mostly because of the threads I've been watching regarding the 6.5. Thank You. [I picked up 2# of Reloader 17 in homage to MCMXI!]

 

[salpal48]

I myself have been using IMR 4350 for years. The burning rate are next to each other on the Chart. If that means anything. I recently used H 4350 . using the same Loading data. . I don't load to max and to me there was no difference In shooting. . To say it is Identical. Thats different. I found @ 100 yards . I did Re-adjust My scope.. On certain load Data. There Loads are within 1 grain of each other
Personally I believe Hodgens is Looking to Discontinue The IMR line and replace with There H line. This might be the way to Do that

 

[ArchAngelCD]

IMR4350 and H4350 are extremely similar but not the same just like both 4895 powders. The two 4350 powders are made in different plants and one is slower than the other. Burn rate charts will tell you one powder is faster or slower than another but not HOW MUCH faster or slower. H4350 is less temperature sensitive than IMR4350 too.

According to Hodgdon they are not looking to replace IMR powders with their name powders. They are committed to keeping the IMR line healthy and I tend to believe them since the 3 new Enduron powders were released under the IMR brand name.

 

[jmr40]

I've used both in my 30-06 with similar results. They are very similar, but load data isn't exactly the same. My best loads in each were within 1-2 gr of each other. I usually got 15-25 fps more speed out of the IMR version with identical accuracy.

I have chosen H4350 however as my preferred powder because it is more resistant to temperature extremes. I've had no problem using IMR4350 when H4350 wasn't available though. The temperature sensitivity isn't something I worry about a lot. But if accuracy and speed are equal why not choose the powder that will be less effected by extreme temperatures.

 

[Slamfire]

I shot H4350, IMR 4350, and AA4350 in the same rifle with the same components. I am of the opinion that lot to lot differences are the sources for the differences you see as data in load manuals. That is, there is no real difference in performance between any of these powders that cannot be explained as differences between blended lots. Which all of these powders are, blended from base stocks to an bounded average. Accurate Arms told me that the industry standard for blended lots was 10%, but they were striving for 5%.

Accurate Arms also told me that AA4350 was a copy of IMR 4350, blended to copy the pressure curve, within their tolerances. I would have to look, but I recall that most of the Hodgdon powders claimed to be copies of the IMR 4350 powders, upon their initial introduction. At the time they were selling their powders based on price, if their powder is the same as a Dupont powder, but cheaper, well, which one are you going to buy.

I don't know how great the monopoly is for the powder industry, it seems to have been consolidated under one or two Corporations, but I really doubt that there is all that much difference between brands anymore. How many decades did it take for shooters to realize that HP 38 and W231, and W231 and H110 were the same powder? I remember Ken Warner castigating W231 as a propellant in the 45 ACP, but praising HP38 to the high heavens. Now, just what was he smoking to see a difference?

 

[farmerboy78]

I have loaded and shot imr 4350 and h 4350 with the same powder charge in a few different calibers (7.62x54r, 35 whelen, .270, and .25-06) with little to no discernible difference and they hit poi to little or no difference. And I now use accurate 4350 in my 6.5 Creedmoor. I say keep them both, work up a load with both, and have a fall back powder in case powder gets hard to find for you.

 

[GooseGestapo]

Fwiw; I used IMR4350 a long time before H4350 came along.
I have/use both. Love both!

IMR tends to be a tad faster, more temp sensitive and..... (Drum roll) MORE accurate!
However, RL17 combines the best of both.
I let the RIFLE decide which it prefers! You should too!

 

[ants]

4350, 4895, 870, other IMR/H powders with same number in the name.

About 10 or 12 years ago I sat in a mini-seminar at the Shot Show, one of the Hodgdon sons was on a panel. The question of H versus IMR rifle powders came up.

According to that Hodgdon, they are not the same powder. When they order the powder from the mill, the purchase order lists specific characteristics such as heat of explosion/potential, specific heat, progressive burning limit, coatings, coating depth, dry density, etc. Process technology for making the powder is the same, but they tweak it one way or the other to match the criteria on the purchase order. So H and IMR powders are similar and maintain similar names, but they are not the same powder. This is also true for a few powders from other manufacturers like Accurate (for instance H870 and AA8700). Same process technology, but the criteria vary.

For IMR powders they continue to use the old DuPont/IMR criteria. Before Hodgdon became associated with IMR they had already developed their own performance criteria for H powders, and today they continue to purchase H powders on those factors.

Bottom line: They make each product to a separate set of criteria, thus the two products are not the same and require separate data. But since they do originate from the same milling technology with similar kernel geometry, one powder that works well for you might indicate the other one may also be satisfactory, but use appropriate data for each. They aren't the same.

 

[Rem700CDLSF3006]

I shot both in my 30-06 love both but I get a little more velocity out of H4350 with Identical accuracy

 

[Kaldor]

For 6.5 CM, H4350 all the way. There is a reason that 90% of the people that shoot CM in competition use it. It simply gives the best mix of accuracy and velocity.

Good data here:
http://precisionrifleblog.com/2015/12/27/best-bullets-brass-primers-powder/

 

[Slamfire]

Bottom line: They make each product to a separate set of criteria, thus the two products are not the same and require separate data. But since they do originate from the same milling technology with similar kernel geometry, one powder that works well for you might indicate the other one may also be satisfactory, but use appropriate data for each. They aren't the same

What you have written is interesting. But, whatever manufacturing or consistency differences may exist between these powders, in my guns over my chronographs, I cannot measure these characteristics, therefore, are these differences without any distinctions?

When it took one grain more of H4350 to have the same velocity for the same components as IMR 4350, is that significant? I am going to say no, because it takes only a couple of kernels of powders to make a ounce grain. I do not consider that a significant difference because I have seen the same weight differences between lots of same brand name blended powders.

Advertisers can spread the thickness of a human hair to bridge the Grand Canyon, the long way! Take for example the threads which go to hundreds of posts, claiming the 270 Win is better than the 30-06, or visa versa. Where did these posters learn these claims and are the differences significant, as they claim, on target? Posters were taught by Corporate Advertisers that their products, with less than a human hair difference between the competition, are
significantly better, and hardly any test the claims to see if there actually is a difference.

Until companies can put out a product which I can see differences between it and the others, using the test instrumentation I have, which is components, rifle, and chronograph, than I am going to tell people: buy by price.

 

[ArchAngelCD]

What you have written is interesting. But, whatever manufacturing or consistency differences may exist between these powders, in my guns over my chronographs, I cannot measure these characteristics, therefore, are these differences without any distinctions?

When it took one grain more of H4350 to have the same velocity for the same components as IMR 4350, is that significant? I am going to say no, because it takes only a couple of kernels of powders to make a ounce grain. I do not consider that a significant difference because I have seen the same weight differences between lots of same brand name blended powders.

Advertisers can spread the thickness of a human hair to bridge the Grand Canyon, the long way! Take for example the threads which go to hundreds of posts, claiming the 270 Win is better than the 30-06, or visa versa. Where did these posters learn these claims and are the differences significant, as they claim, on target? Posters were taught by Corporate Advertisers that their products, with less than a human hair difference between the competition, are
significantly better, and hardly any test the claims to see if there actually is a difference.

Until companies can put out a product which I can see differences between it and the others, using the test instrumentation I have, which is components, rifle, and chronograph, than I am going to tell people: buy by price.

All good points and I agree. It does seem for me though when loading a 168gr match bullet in a 30-06 I get the best accuracy from 58.0gr H4350 but only 57.0gr IMR4350. I do have a feeling this is only due to the powder lots and their accuracy is actually not a full grain apart.

 

[CANNONMAN]

Thanks guys! Kaldor... My hat's off to you and I offer you a couple of my "Atta-Boys"! Thanks for heads up.

 

[Kaldor]

Thanks guys! Kaldor... My hat's off to you and I offer you a couple of my "Atta-Boys"! Thanks for heads up.

Thanks. I know a few guys have had luck with H4831SC as well. A friend of mine has used 4831 SC alot because H4350 is like unobtanium it seems.

I know alot of guys dont buy into the hype, and thats fine. However, this is a case where H4350 really is that much better than everything else, especially if you really need accuracy.

 

[RPRNY]

Fwiw; I used IMR4350 a long time before H4350 came along.
I have/use both. Love both!

IMR tends to be a tad faster, more temp sensitive and..... (Drum roll) MORE accurate!
However, RL17 combines the best of both.
I let the RIFLE decide which it prefers! You should too!

I concur with the above.