H4350 vs Imr4350 vs Acc4350
- Thread starter 6MMsteve
- Start date
Personally, I find that the accuracy of my 25-06 likes the IMR brand better than H4350, but that may be due to fact that I've used it for years (at least 20) and have only in the last couple years started messing with the other. I have no doubt you'll find people that will swear that one is much better than the other though.
They are two different powders which share similar burning rates and specific energy levels made by different companies on opposite sides of the planet (IMR in Canada; Hodgdon in Australia). They do a similar job in the same set of cartridges using similar (but not identical) charges. Sometimes a cartridge noticeably prefers one over the other. If you already have an H4350 load, don't simply substitute the IMR version for it - look up new loads and work up to maximum again.
For many users, the biggest difference is that the Hodgdon version is one of its 'Extreme' range and is treated to reduce temperature sensitivity, whilst the old IMR version isn't and may see bigger pressure / velocity changes according to season and weather. In practice, IMR-4350's reputation isn't a bad one in this respect compared to some. (Nevertheless, General Dynamics IMR is currently introducing new 'Enduron' grades which may ultimately supersede existing IMR equivalents and which are claimed to be exceptionally temperature stable.)
For many users, the biggest difference is that the Hodgdon version is one of its 'Extreme' range and is treated to reduce temperature sensitivity, whilst the old IMR version isn't and may see bigger pressure / velocity changes according to season and weather. In practice, IMR-4350's reputation isn't a bad one in this respect compared to some. (Nevertheless, General Dynamics IMR is currently introducing new 'Enduron' grades which may ultimately supersede existing IMR equivalents and which are claimed to be exceptionally temperature stable.)
I have never used H4350 but I have shot up lots of IMR before trying 3 or 4 cans of AA 4350.
They both shot well in 6mm, 243 and 25-06 rifles with near max loads. I think the AA 4350 produces more ash and crud in the bore.
Neither produces a huge flash. I gave up on the Accurate powders when their cost went from about half of the IMR price to about the same.
That and some of the AA powders seem to come from China (2495) one time and the Czech Republic (5744) the next and then several were of unknown origin (4350 and 2015). I am not much of a powder player since it does have a shelf life , so I keep my supply pretty lean and use only propellants that I expect to be around a long time.
They both shot well in 6mm, 243 and 25-06 rifles with near max loads. I think the AA 4350 produces more ash and crud in the bore.
Neither produces a huge flash. I gave up on the Accurate powders when their cost went from about half of the IMR price to about the same.
That and some of the AA powders seem to come from China (2495) one time and the Czech Republic (5744) the next and then several were of unknown origin (4350 and 2015). I am not much of a powder player since it does have a shelf life , so I keep my supply pretty lean and use only propellants that I expect to be around a long time.
Back in the days of Accurate Arms Inc before the outfit was bought by the present owners Western Powders, most AA rifle powders came from Explosia A.S. in the Czech Republic - 2015, 2230, 2460, 2520, 4350, 3100, 5744 and several others. After the buyout, Western sourced its grades elsewhere. Several of the current ball types are made by PB Clermont in Belgium (which also makes Ramshot ball powders). I believe the extruded types including Accurate-4350 are manufactured for Western by the same plant which makes the IMR grades - General Dynamics' Valleyfield, Quebec facility.
Your rifle will tell you which one it likes the best. That said all three 4350's fall within a certain burn rate. IMR is the fastest. Hodgdon is a little slower and Accurate a little slower than still. Do not transpose a load for one powder for another. Work up with the powder you have.
I've found in my rifles Accurate 4350 is a good powder when the H version is a little to fast and 4831sc a little to slow. Then again each rifle is different.
I've found in my rifles Accurate 4350 is a good powder when the H version is a little to fast and 4831sc a little to slow. Then again each rifle is different.
The difference to me that matters is the powder temperature stabilization of the 3 Hodgon I have found gives me the least amount of variation. By a lot .
Larry
Larry
http://bulletin.accurateshooter.com/2016/07/powder-comparison-test-h4350-vs-imr-4451/
Here's another article that cross references HPowders with IMRPowders:
http://bulletin.accurateshooter.com/2016/06/guide-to-imrs-enduron-powders-what-you-need-to-know/
Here's another article that cross references HPowders with IMRPowders:
http://bulletin.accurateshooter.com/2016/06/guide-to-imrs-enduron-powders-what-you-need-to-know/
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I always liked the IMR powders. One important thing to note it that some of the older IMR powders were developed specifically for a given military cartridge. Thus IMR (Improved Military Rifle) 4895 was specifically developed for a 150 gr weight range spitzer bullet in 30-06. The IMR label was used across all the other powders back when it was E. I. du Pont de Nemours and Company and that labeling stuck. IIRC the original formula for IMR 4895 was lost in a fire, a closely guarded trade secret so there where not back up copies. Phil Sharpe used to write interesting articles and a few chapters in books on powder manufacture sixty or seventy years back.
Anyhow, IMR 4350 was about ideal for a 130 gr bullet in .270, and IMY 7828 was developed for the then new .300 Winmag family of cartridges which by using the same basic parent case included the 7mm Rem Mag.
Anyhow, IMR 4350 was about ideal for a 130 gr bullet in .270, and IMY 7828 was developed for the then new .300 Winmag family of cartridges which by using the same basic parent case included the 7mm Rem Mag.
It was developed by Du Pont specifically for the 7mm Remington Magnum whose introduction shortly preceded that of the .300 Win Mag. They were the last of the 1950s / 60s series of 'short magnums' as they were called. (Short that is against the 3.5" COAL H&H family of belted magnums and their 'improved' Weatherby developments.)
The party originally behind the 7RM was 'The Flying Bowmans', retired aviation legends in their own lifetimes Les and Martie Bowman, a married couple who'd retired as millionaires to a huge upland tract of land in Wyoming populated by large elk. They went into the upmarket game outfitting business and marketed the spread as 'Elk Heaven' to wealthy clients. Bowman soon noticed that many clients could't cope with the existing larger calibre magnums and poor shot placement led to too many wounded animals having to be tracked and finished off. He argued for a 'short magnum' using the 2.5" 458/260/338 Winchester Magnum case but in 7mm and using 160-175gn bullets at around the 3,000 fps mark. He set about creating a 7mm Winchester Magnum wildcat, and presumably tried to sell the idea to that company, but if so was unsuccessful - unsurprising in that Winchester was in the final stages of developing the last of its quartet, the .300 Win Mag. Bowman was not only rich but had excellent contacts in the shooting world and had influence. He got benchrest and sporting shooting guru and writer Warren Page behind his idea and was also friends with Remington's chief development engineer Mike Walker whom he invited out to Elk Heaven to use the wildcat in its proper environment. To get Remington on side he even had cases made up with the headstamp '280 Rem Magnum'. Mike Walker was duly impressed and went off to sell the idea to the Remy bean-counters who were initially 100% opposed to the concept 'as Americans don't buy 7mm cartridges'.
He eventually won them over and got permission to develop a Remington version of the concept, the 7mm Remington Magnum and after its introduction was vindicated by it being the most successful of the 1960s' newcomers. It was helped by being launched in partnership with the then new and to be wildly successful Remington 700 rifle. For years, Remington couldn't keep up with orders for 700s chambered for the cartridge.
One development problem Mike Walker faced was propellant as there was nothing ideally suited to the 7RM/175gn combination available off the shelf. Winchester as part of the Olin Corporation used Olin manufactured ball powders in its cartridges. (And had had great problems with compressed loads of ball powder in the early production of the .458 Win Mag.) Remington turned to DuPont and asked if it could come up with something suitable for the new 7mm - answer IMR-7828. For some years it was only available to the factory, so handloaders couldn't match factory Remington velocities. Back then 7828 was regarded as incredibly slow burning for a rifle cartridge. In fact, if you read P O Ackley's 'Handbooks' he'd stated only a few years earlier that the then slowest burner available to handloaders IMR-4350 was such a slow burning powder it had very few uses in normal shooting and loading.
Back in the late 60's I used H-870 and H-570 in my Rem 700 7mm Rem mag with 160 and 175's. I shot that barrel out with those powders, the 160's at 3100 F/S and above were brutal from a bench but killed a lot of game for me. It was later when I bought a Colt light rifle in 7mm RM that I discovered IMR 7828 and a 150 gr bullet used on mule deer, sheep, and antelope and that is my story and I'm sticking to it.
let your gun tell you what it likes! I have a custom 6.5x47 that loves h-4350 but hates any load of imr-4350 that I tried to put in it! also imr was a lot dirty.
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