Is IMR 4227 and H4227 the same powder?

SLT223 · Nov 8, 2014

I found an 8lb keg of IMR4227 and I have a bunch 158gr .357 JSP heads I'd like to load. I was planning on going to the old Hodgdon Reloading Data Center online, but noticed they show H4227, not IMR 4227. What gives? Why no IMR4227 load data? Are they the same product?

Edit:
I do have Lyman's #49 reloading manual, which does have 158gr jacketed/IMR4227 load data, so I do have a data source, I'm just curious why Hodgdon doesn't list IMR4227.

KLYDE · Nov 8, 2014

Hodgdon's burn rate chart list IMR at #65 and the H at #66. Load data that lists both will show a wee bit heavier load using the H versus the IMR. IIRC I read somewhere that current production IMR is the same as the H but I can't confirm that.

What make bullet are you using?

Sid V. · Nov 8, 2014

if you go to hodgdon.com you you will find data for both.sorry shift button not working.---dennis v.

SLT223 · Nov 8, 2014

KLYDE said:
What make bullet are you using?

Not sure Klyde. They are pull downs from Rocky Mountain Reloading. They mic at .357 .

SLT223 · Nov 8, 2014

Sid V. said:
if you go to hodgdon.com you you will find data for both.sorry shift button not working.---dennis v.

Yeah I see it now. It's because there was no listing for 158gr...they only list it for 140gr. Kinda strange they don't have a 158 load for it.

KLYDE · Nov 8, 2014

SLT,
Hornady 8th has .357 data for the 158 gr. It lists both IMR and Hodgdon.

IMR 4227
start 12.4=1000 fps..................max 14.5=1150 fps

H4227
start 11.9=1000 fps..................max 15.1=1200 fps

This data is applicable to the 158 gr HP and FP XTP.

May give you a general idea.

M3Stuart · Nov 9, 2014

Hey OP;

I actually called Hogdon about this very issue; "...are they interchangeable?"

Answer: "Virtually." Customer Service said to work up from the bottom of the lower load data and you'll be fine.

Feel free to call them yourself. They were quick to answer, knowledgable and very helpful. You could even ask them about your specific load.

KLYDE · Nov 9, 2014

M3Stuart said:
Hey OP;

I actually called Hogdon about this very issue; "...are they interchangeable?"

Answer: "Virtually." Customer Service said to work up from the bottom of the lower load data and you'll be fine.

Feel free to call them yourself. They were quick to answer, knowledgable and very helpful. You could even ask them about your specific load.

Thought I had read that the current production IMR had been changed to the same burn rate as the Hodgdon. Your call to Hodgdon seems to have validated that claim. As always a proper work up of the load is essential.

Doubless · Nov 9, 2014

KLYDE said:
Thought I had read that the current production IMR had been changed to the same burn rate as the Hodgdon. Your call to Hodgdon seems to have validated that claim. As always a proper work up of the load is essential.

I would respectfully disagree. I do not believe the Hodgdon rep "validated" the two powders as being the same. In my opinion, that is NOT what he said: I read what he said as "work up using the IMR load data, and if you don't reach maximum pressure signs by the time you reach the top of the load chart, judiciously use the Hodgdon load data until you reach max pressure."

Every firearm is a law unto itself, and what is max in my GP 100 may well be above what is max in your Security Six, Model27, 586, etc. (and in all likelihood will be...).

IF H4227 and IMR 4227 were the same powder, load data for a given projectile would be exactly the same between the two. To me, the fact there is a difference means the two, while VERY close, are NOT the same.

WR Moore · Nov 9, 2014

I do believe there's already a thread on this subject.

ArchAngelCD · Nov 9, 2014

H4227 is discontinued
IMR4227 is still for sale.
To confuse things, in reality IMR4227 is the powder that was discontinued and the H4227 formulation was renamed and is being sold as IMR4227.

44wheelman · Nov 9, 2014

That would be the Australian imr, not the Canadian imr, correct?

KLYDE · Nov 9, 2014

ArchAngelCD said:
H4227 is discontinued
IMR4227 is still for sale.
To confuse things, in reality IMR4227 is the powder that was discontinued and the H4227 formulation was renamed and is being sold as IMR4227.

Thanks for clarifying Arch Angel. That is exactly what I had read but couldn't remember where. (wasn't here). I have noticed even recently published loading manual data still reflects the different burn rate. I'd figure they would have to continue to publish such for any older powder still on the streets. Hopefully the Hodgdon rep doesn't mislead any inquiring loaders and notes that only the "current production" is the same product.

I still have some older IMR and strictly go by the applicable load data as it is slightly faster than the H.

Doubless: read post #2, then #6. As I posted, I'm well aware of the difference between the old stock. I was referring to the new production as being one in the same. Probably didn't explain fully. Arch Angel clarified. Really not an ideal situation for sure.

Is IMR 4227 and H4227 the same powder?

SLT223

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KLYDE

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Sid V.

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ArchAngelCD

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44wheelman

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