I'm a bit confused about using IMR 4227. Most powders have good load data that is easy to follow, but IMR 4227 is apparently (according to Internet chatter) not the same powder it used to be, and is closer to H4227 (which is no longer made). I contacted Hodgdon about this, and they simply said that H4227 was no longer made, and that the two were different powders, but we're so close in burn rate and fill ratio that I could use either powder's data as long as I start low and work up.

This is a bit confusing because for .357 rifles and carbines, Hodgdons own load data is the same for 125 gr and 158 gr bullets, but all other weight bullets only show H4227 load data. It gets worse for pistol data. .357 data for 140 gr bullets (the only one listed for IMR 4227) shows a range of 11-13 gr of IMR 4227, and 16.2-18 gr for H4227. All other weights of bullets only list H4227 as an option. .38 special data only lists H4227.

Why would load data for 125 and 150 gr bullets be the same for carbines, but for 140 gr in pistols there is such a difference? Also, why do some loads only list H4227 data? Is it safe to use H4227 data in all situations?

I'd suggest you forget the "internet chatter" and stay with published data. IMR4227 data has been published for years. It should not be hard to find. I don't have a lot of experience with H4227 but I recall, I think from my .22 Hornet days, that there appeared to be enough difference that I always bought and used only DuPont. I suppose a .357 in a carbine would be more forgiving, but why take a chance? Just use published data.

IMR (Improved Military Rifle)-4227 was a smokeless propellant made by DuPont prior to the acquisition of their propellant operations by Hodgdon in 2003.

H (Hodgdon) 4227 was a smokeless propellant made by Hodgdon with similar characteristics to IMR-4227 intended to be a competitor with IMR-4227 in cartridges where the DuPont powder was used. Hodgdon used the 4227 number to suggest the powder could be used in cartridges where IMR-4227 was suitable; not to say they were identical powders.

IMR-4227 is a "fast" powder for compact rifle cartridges or a "slow" powder for pistol cartridges. I suspect in the longer barrel IMR-4227 has time to burn to maximum pressure before the bullet exits the barrel, thus explaining why the load for two bullets would be the same.

Not to sound flippant, but where H4227 is the only powder listed, it was the only powder tested for that cartridge and bullet weight. Because of considerations involving cost, time, access to test facilities, reported user demand and the like, manufacturers do not test every powder and bullet combination for every cartridge.

No.

They are not the same powder.

I know you can find posts by people saying they used H4227 and IMR-4227 interchangeably and never had a problem. I liken them to the people who run red lights and justify themselves by saying they haven't had an accident, yet.

Despite all the good stuff on the web, you need good teloading manuals. H4227 is an older powder so older manuals will be helpful. I keep all of mine, going back to speer #11. Yes, they are diff powders.

__________________
NRA Cert. Inst. IDPA CSO

Mr. Flinstone, you ask very good, reasonable and cogent questions.

Speer #11 was my first reloading manual. I chose it because it was cheaper than the other manuals at the store at the time. Prior to that, I had used the data that came with my original Lee Loader or in manuals my friends had let me borrow.

While IMR4227 and H4227 may not be identical, they will not be different enough to make much difference in performance. 4227 is a reasonably good propellant for light lead bullet loads in center fire rifle calibers. I recently made up some .300 Savage loads using both IMR4227 and H4227 (23 grains) and 165 grain GC lead bullets. While the powders look and feel slightly different, the average MVs they produced were very close (around 2000 ft/sec) from my Remington Model 81.

Interchanging 2 different powders,even if they bear the same number is not a practice I'd recommend.Luckily,the 4227s are,in a handgun case such a slow burner that it probably forgave a few careless reloaders who might have tried it.
I've been using IMR 4227 in .44 Mag handguns and in numerous rifle cases with cast bullets and I don't remember being disappointed.But I was following published data.
Like stated above,the best solution in your case would be to get a few reloading books from reputable houses(Lyman,Speer,Horandy,Sierra,Lee and a few others).Besides,in the books,you generally get some usefull extra tips.I know I'm not too old to still learn new things.
Qc

Per Hodgdon.........IMR4227 and H4227 were different powders and used to have different charge rates. Hodgdon discontinued IMR4227 and renamed the old H4227, IMR4227. So............if you are using newer, current production IMR4227 you can use old H4227 data or new IMR4227 data. If you are using old production IMR4227 you should use old IMR4227 data.

Confused yet?

If the corporate lawyers let them do this they must have figured it would not "blow up" on them.

__________________
Certified Curmudgeon

Please provide substantiation for this. This myth has been floating around long before the 2003 acquisition of DuPont's powder operations by Hodgdon.

I have yet to see any communication from Hodgdon confirming this and without it I will continue to regard the H4227=IMR4227 equality as a myth and advise everyone else to do the same.

You have no idea what Hodgkin's corporate lawyers said or did not say. Don't assume that buck469XVR's unsupported statement is accurate or true. Anyone on the internet - including me - can post anything they want - truth or fantasy - so question everything and accept nothing at face value or authoritative unless accompanied by substantiation - particularly if it meets with what you would like to believe.

If you want to treat H4227 as equivalent as IMR4227, contact Hodgdon who makes them both and ask if they are the same.

You are quite correct that IMR-4227 and H4227 are not the same powder.

And your experience with 300 Savage does not translate directly to the 357 rounds the OP is loading.

As to the rest of your post, keep in mind you're advising a relative newbie, do you really think it is responsible to suggest that they are "close enough" to be used interchangeably?

I don't.

Just for reference, this is the message I sent them, and their reply.

Submitted on Tuesday, April 11, 2017 - 9:10am Submitted by anonymous user: [170.185.139.19] Submitted values are:

Name: xxxxxxxxxxxxxx
Email: xxxxxxxxxxxxxx
Phone Number:xxx-xxx-xxxx
Message: Are Hodgdon's H4227 and IMR4227 the same powder with different labels, or different powders completely. Do they use the same load data, and will load data from older manuals still be accurate?

Subject: Form submission from: Contact

H4227 is not made any more, the two powders are not exactly the same but they are so close in burn speed and fill ratio that we say that you can use the same data as long as you use the starting load and work up to the max watching for pressure signs.

Mike Van Dyke
Customer Service Representative
Hodgdon Powder Company
6430 Vista Drive
Shawnee, Ks. 66218
913-362-9455 Ext. 109

Well, for my money, if Hodgdon's lawyers are allowing them to advise customers to use the starting data for the two powders interchangeably, then they must be mighty darned close to being the same thing...

Chiris Hodgdon discussed h4227 and imr4227 in an interview back in 2014. He said the data is interchangeable.

Episode 185 - Interview with Chris Hodgdon 2014 - YouTube