Hodgdon vs IMR

[Dogbone13]

What's the difference, if any, between Hodgdon and IMR powders with the same numbers like 4227, 4198, etc?

[redhawk0]

Slightly different burn rates. I never interchange data from IMR to H powders. There is enough of a difference that when you get within 90% of max loads there could be dangerous pressure variances.

Most of the difference is in the "coatings" uses on the powder grains. The H powders seem to be able to handle temperature extremes better than the IMR...but that's up for debate also.

redhawk

[Larry Gibson]

What's the difference, if any, between Hodgdon and IMR powders with the same numbers like 4227, 4198, etc?

IMR powders are made in Canada. The Hodgdon powders are made elsewhere (USA, Australia, etc.)

There can be subtle differences in burn rates so the data for one does not always apply to the data of another of the the same number.

[charlie b]

Or better, what is the history behind IMR and Hogdon using the same numbers? Govt contracts?

[Burnt Fingers]

What's the difference, if any, between Hodgdon and IMR powders with the same numbers such as 4198, etc?

There's a lot of difference. You can browse the Hodgdon reloading site and see the different load data.

[Texas by God]

IMR kernels are grayish black, Hodgdon kernels are olive brown. According to the bits I just spooned out of both brands of 4350. I think some may be identical burn rate-(4227)- but most are not as the manuals will tell you. I’ve used IMR 4895 with H4895 data without drama, but mine weren’t maximum loads at all. I do believe that the companies wouldn’t use like numbers for drastically different powders from a liability standpoint.

[oldsman]

the powder is being manufactured at different plants more likely different countrys witch will cause the slightly different burn rate
for the same number, why they use the same number or how they come up with that number ?

[oldsman]

just notice the other thread on the same subject and that should sums it up
different county different process of manufacture

[Dogbone13]

Thank you gentlemen. Appreciate your input.

[charlie b]

why did they use the same numbers?

[Petrol & Powder]

why did they use the same numbers?

To give people on firearm's forums something to talk about :bigsmyl2:

[Larry Gibson]

As explained on your earlier thread;

IMR powders are made in Canada. The Hodgdon powders are made elsewhere (USA, Australia, etc.)

There can be subtle differences in burn rates so the data for one does not always apply to the data of another of the the same number.

[fredj338]

Just understand thst they ate NOT interchangable. Diff data for each.

[lotech]

Many of the Hodgdon rifle powders are "Extreme" versions, less sensitive to temperature fluctuation than the older IMR powders. That may not matter for some shooters, but I stopped buying IMR powders years ago. H4895, H4350, and H4831 are the Hodgdon powders I use the most. As for velocity and accuracy comparisons between the two brands, I doubt you'll see a significant difference, if any, except maybe with the recommended charge weights.

[Texas by God]

There is no H equivalent for IMR 3031, 4064, or 4320. Just saying. IMR powders have been my standards for rifle loads for decades. Of course I use some others, too but I like my IMR powder. Like Coca- Cola- don’t mess with it.

[DonHowe]

I cannot state the rationale nor the thinking behind duplication of numbers today. I do know that the IMR (improved Military Rifle) designation was initiated and owned by the Dupont powder company which made, among others, powder for the US military. In the aftermath of WWII a guy named Bruce Hodgdon got into the powder by buying and reselling bulk surplus powders (4831 and 4895). These powders WERE IMR powders. That is how the number duplication started. As Hodgdon added to his line powders duplicating IMR numbers (4227, 4198,etc) someone other than Dupont made them so they were close but not identical. The same was true for 4831 and 4895 when the war surplus stuff was gone. Things diverged farther when Dupont sold off the powder mfg business which them became IMR.
As for number duplication, simply put, someone else wanted a share of the market and before burning rate charts it likely seemed the easiest way to convey the intended usage.

This is intended to be a rough sketch only.

[higgins]

There may be some difference between IMR and H-4895 since Hodgdon recommends their version for reduced loads. Maybe the IMR 4895 doesn't burn as well at lower pressures.

[303Guy]

Varget might be a close substitute for IMR 4320. I used to use a powder made by Somchem that had load data very close to 4320. Varget seemed close to that powder in data but not as close as 4320. A characteristic that may make Varget attractive is its apparent fast ignition rate. Faster than the faster burning 4895. Hodgdon do claim it is easy to ignite. So maybe worth looking into.

[Larry Gibson]

There may be some difference between IMR and H-4895 since Hodgdon recommends their version for reduced loads. Maybe the IMR 4895 doesn't burn as well at lower pressures.

Both IMR and H 4895 perform equally well with reduced cast bullet loads, especially if a dacron filler is used.

[charlie b]

DonHowe, thanks. That confirms the information I had heard at one time.

For some reason Hodgdon made a special point of publishing some reduced load data for 4895. Why did they publish reduced data for only that powder and not many of the others that also work well in reduced loads (even without fillers).

I've used 4198, IMR 4895 and Varget for cast loads at reduced velocities, with and without fillers.