H vs IMR 4895 interchangeable?

[NapalmCheese]

I'm having issues from H4895 locally, and a buddy (who owes me a couple of pounds of powder) found IMR4895 near him so picked up a couple of lbs for me.

Now, looking at Hodgdon's M1 Garand Service Rifle data, they list H and IMR at vastly different weights. Those vastly different weights also produce different velocities and different pressures.

Looking at the Hornady manual they list both powders nearly identical to each other and in the same velocity range. Close enough that if no one told me they were different powders, I'd just assume they were different lots of the same powder.

So, do YOU interchange your H4895 and IMR4895 data?

"My" pet load isn't near max for either powder according to Hornady, so I'm just going to load the same and run with it, see how it goes. I should probably run them both over the chrono for giggles.

[ar15barrels]

All the 4895's are generally interchangeable at starting load levels but you should approach max loads through the usual development method to account for lot-to-lot variation which exists across all powders.

[bigbossman]

All the 4895's are generally interchangeable at starting load levels but you should approach max loads through the usual development method to account for lot-to-lot variation which exists across all powders.

How very, very disappointing.

How dare you give sane, thoughtful, and useful advice on an internet forum!

[NapalmCheese]

Yeah, no one telling me I'm going to blow myself up yet!

Thanks, I'm not terribly worried. Interesting to see how different the Hodgdon data is from the Hornady data however.

[BrassCase]

How very, very disappointing.

How dare you give sane, thoughtful, and useful advice on an internet forum!

It's Christmas, it's gonna happen. Just wait till after the first and everything will be back to normal.

[JagerDog]

I've shot quite a bit of 4831, both H and IMR. IMR was a bit faster burning with lower charge weight. Not a lot, but.

At starting loads, they're close enough.

[Txtaxman]

Fun fact. My first reloading manual was Speer Number 7, Copyright 1966, and they only listed 4831, 4350, 4895, 4064, 3031, etc. However, H380 was listed.

[kcstott]

What Randall said.

My opinion is yes they are interchangeable and close to same charge weights in most loads but they are different enough to create problems.

[pacrat]

Fun fact. My first reloading manual was Speer Number 7, Copyright 1966, and they only listed 4831, 4350, 4895, 4064, 3031, etc. However, H380 was listed.

Easily explained by delving into the origins of Hodgdon Powder Co. Initially in the 1940s until the IIRC, early to mid 1970s. ALL Hodgdon powders were MILITARY SURPLUS. Most by Dupont/IMR.

Hodgdon bought hundreds of tons of powder, and repackaged it under his Co Name, for sale to retail outlets for reloaders, at deep discounts.

I can remember walking into Universal Arms, in Paramount, or Matthews, in Downey, both on Paramount Blvd. With an empty coffee can, and buying bulk 4895 for $1.50 a pound. That they got from Hodgdon.

[Fjold]

Here's a link to the burn rate chart created by Hodgdon:

https://bulletin.accurateshooter.com/2022/01/powder-burn-rate-comparison-table-download/

[tuna quesadilla]

All the 4895's are generally interchangeable at starting load levels but you should approach max loads through the usual development method to account for lot-to-lot variation which exists across all powders.

Do you do a new work-up every time you get a new lot of the same powder? I've never done so

[pennstater]

Easily explained by delving into the origins of Hodgdon Powder Co. Initially in the 1940s until the IIRC, early to mid 1970s. ALL Hodgdon powders were MILITARY SURPLUS. Most by Dupont/IMR.

Hodgdon bought hundreds of tons of powder, and repackaged it under his Co Name, for sale to retail outlets for reloaders, at deep discounts.

I can remember walking into Universal Arms, in Paramount, or Matthews, in Downey, both on Paramount Blvd. With an empty coffee can, and buying bulk 4895 for $1.50 a pound. That they got from Hodgdon.

Matthews & Son Gunsmithing in Downey was one of the BEST gunsmithing shops I can ever think of. George and Steve[the son] were exceptional 'smiths. Great shop and Mark behind the counter was a great source of loading info. Miss that shop and those guys.

MLC

[pennstater]

Geez, sorry to hijack. What Randall said is where you should venture. Especially mid loads and up. Again, sorry for the hijack.

MLC

[ar15barrels]

Do you do a new work-up every time you get a new lot of the same powder? I've never done so

If my chrono results show a different velocity when changing lots, I go back and work to my old velocity as the velocity-vs-pressures will generally track across different lots even though the charges may vary.