Thread: 4895 vs 2206h

Originally Posted by Kiwi Greg

A quick check on Hodgdons reloading site shows a bit of a difference between IMR & H 4895

https://www.hodgdonreloading.com/rel...c=true&type=54

Greetings,
You will have noticed that most of the Hodgdon data for the older projectiles has pressure expressed in CUP so it could be 30 plus years old. The IMR data has pressure expressed in PSI so it is much more recent und used a different method of measurement using electronic systems rather than mechanical. To be honest I would be surprised if they were the same. There are three versions of 4895 marketed by Hodgdons. The original milsurp stuff just called 4895. When this ran out H4895 was manufactured by Nobels and now ADI. Dupont started offering IMR4895 after the milsurp stuff ran out. I have used all but the Nobels manufactured stuff, alas in the days before I had a chronograph.
Regards Grandpamac.

Greetings again,
Cross checked with some of the older CUP data for the IMR powders and the current data is clearly hotter. Where the data for both powders is in PSI the data is mostly closer. In any case IMR4895 and H4895 (AR2206H) are different powders and each should be used with the data provided for it, working up from below and chronographing as we go>
Regards Grandpamac.

I did a wee bit of looking into this, last night.

All the tables I checked were consistent with each other and adi and h4895 data were identical. Imr was constant across; lee loader load data sheet, Richard Lee Modern Reloading and the Hodgson's website.

That said Hodgson bought IMR in '03 and potentially they are still using old data? Modern Reloading and the lee loader would likely have pre'03 data.

One observation, imr4895 is faster on paper with a higher don't exceed level. If you went Over the adi don't exceed level wouldn't you get similar speeds?

Also, I haven't poured any imr out yet but could the imr have a different cut length or grain size creating a different burn rate?

Possibly dumb questions from a newbie but my 2c. I have the powder now so I'll find out. Surely the difference won't be massive and the deer don't prefer adi over imr....

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Originally Posted by Rn-85

I did a wee bit of looking into this, last night.

All the tables I checked were consistent with each other and adi and h4895 data were identical. Imr was constant across; lee loader load data sheet, Richard Lee Modern Reloading and the Hodgson's website.

That said Hodgson bought IMR in '03 and potentially they are still using old data? Modern Reloading and the lee loader would likely have pre'03 data.

One observation, imr4895 is faster on paper with a higher don't exceed level. If you went Over the adi don't exceed level wouldn't you get similar speeds?

Also, I haven't poured any imr out yet but could the imr have a different cut length or grain size creating a different burn rate?

Possibly dumb questions from a newbie but my 2c. I have the powder now so I'll find out. Surely the difference won't be massive and the deer don't prefer adi over imr....

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Yes I'll use the imr data when loading imr.

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Originally Posted by Rn-85

Yes I'll use the imr data when loading imr.

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It would be best to think of IMR4895 and H4895 (AR2206H) as different powders as you propose. True they are similar in burning speed but each can be slower or faster than the other depending on what is being loaded. IMR4895 was developed in the 1930's for the .30-06 Garand rifle and is more temp sensitive than AR2206H so two different powders. IMR loads have increased substantially over the last 50 years for whatever reason, possibly the different pressure measuring system.
Regards Grandpamac.

Originally Posted by grandpamac

It would be best to think of IMR4895 and H4895 (AR2206H) as different powders as you propose. True they are similar in burning speed but each can be slower or faster than the other depending on what is being loaded. IMR4895 was developed in the 1930's for the .30-06 Garand rifle and is more temp sensitive than AR2206H so two different powders. IMR loads have increased substantially over the last 50 years for whatever reason, possibly the different pressure measuring system.
Regards Grandpamac.

So then the power being more sensitive, would it perform difference in different situations? What situations? Does this make that powder less usable over a range of hunting environments?

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This got me thinking. Velocity and pressure are quite linear within the normal pressure ranges so I gathered up some data for 150 grain projectiles and my calculator. In 1976 Dupont listed 44.5 grains of IMR4895 for 2,780 fps as max. In 2003 IMR listed 45.5 grains of IMR4895 for 2,880 fps. The current Hodgdons data lists 47.3 grains of IMR4895 for 2,920 fps. A big range of both charge and velocity. Using the current Hodgdons data and interpolating velocities for 44.5 and 45.5 grains gave 2,745 and 2805 fps respectively. Cases, primers and projectiles varied but the predicted and actual results were close enough to indicate that powder speed had not changed that much, just the method of pressure testing. The Hodgdons data for the 150 grain and H4895 closely matched the IMR 2003 data.
Regards Grandpamac.
PS. Just spotted your post. For NZ hunting conditions you can probably ignore the temp sensitivity, Just don't leave the cartridges lying in the sun or on the dash of your ute.
GPM.

Having done a bit of digging into light loads recently, with Hodgdon suggesting that H4895 can be used for 60% of max loads, that would seem to be the critical area where they might not be interchangable.

Then I found this.

Originally Posted by Vanman

Having done a bit of digging into light loads recently, with Hodgdon suggesting that H4895 can be used for 60% of max loads, that would seem to be the critical area where they might not be interchangable.

Then I found this.

I've fiddled with light loads a bit and found that at 80% and above results are good but can burn a bit dirty when you go below that. I had seen Johns note in Handloader plus the original article. Originally my light loads were used as a low recoil target load in my .308. More recently as a light load in the .303 that lets cases last a very long time.
GPM.