Home Forums Hunting & Shooting Ask The Gunwriters IMR And H4895 Question

I will be needing some reduced recoil loads next summer. I have a good supply of IMR4895, but no H4895. Way back in the dark ages I used reduced loads of IMR, but the manuals seem to only recommend reducing H brand these days. Is there a reason that the change occured? Maybe by next summer this craziness of reloading and ammo shortages will be over. Yes, I know and shoot cast bullets. Yes I have 5744 and 4227, but I would like to use some of my 4895 with jacketed bullets.
My face isn't pretty but I'm attached to it and as I get older I've become more safety conscious. Can I reduce IMR4895 like H4895?
Thanks
Bfly

Won’t quote, but This JB article might answer your question.

https://www.handloadermagazine.com/reduced-rifle-loads

Which cartridges and how reduced are you wanting to go?

You can go down to 60% of a listed MAX load of IMR4895 OR H4895.

Hodgdon no longer lists 60% reduction for IMR4895. I asked their head ballistician why, and he said it was because they started getting inconsistent pressures when reduced that much during testing with a piezo system--which didn't show up in copper-crusher testing.

The IMR version is still awfully good for "somewhat reduced" loads.

Is that to imply they didn't see the same with the H variant?

Thanks John. I stand corrected.

Thanks. I should have looked through my old Handloaders.
It has been my experience that as technology allows us to better understand what is happening, we need to adjust our old ways. I think I'll just use some of my 5744, and keep the 4895 for full power stuff when I can shoot them again.
Bfly

I don't trust Hodgdon on much of anything. To me, on a couple powders I am familiar with, they 'shade' the data to make the new names look better. I have years of experience with BLC-2, in .308 and 8x57...with the same rifles and a proven accurate chrono. Started substituting CFE .223 when it became available, performs exactly the same, grain for grain. Then you go to recent printed book like Hogdons Annual Manual, and on the old BLC-2 they list a lesser charge and velocity, which at first glance makes CFE look a little better....until you look at the pressure data and/or check it by a firing test. I have used a ton of H380 in the 7.62 x 54 R Finn 39, guess what, LVR gets same results grain for grain, at least well within lot to lot tolerances. And to further annoy the shooter, they claim if you use anything but Hornady flex tip bullets, with LVR, and the exact published charge...you will die, and kill everyone within miles, cows will go dry and hens will quit laying. In my cautious experimenting. Assuming there is a close relationship betwixt pressure and velocity, I say Humbug. Any time you need not make sight changes at 600 yards by switching powders, I'd say you are for practical purposes, burning the same powder. One man's opinion.

There is no "imply." They did not see it with H4895, which is a different powder than IMR4895, one of the Extremes that have been produced in Australia since the 1990s, instead of the present IMR4895 made in Canada.

Might also point out that the powders named H4895 and IMR4895 have both changed over the past few decades, both in where they're made and the exact formula.

Then you're FOS. Won't argue, since it would take too much time and energy, and probably wouldn't change your mind. But will say is that switching from copper-crusher pressure testing to piezo-electronic transducers changed things considerably over the last couple decades.

Does that make it unsafe, they had done the 60% reduction for years apparently without incident.Is the modern IMR4895 different than the older IMR4895?

you specified the 4895s but i have had better results with 4198. Usually, this is with 308 7x57 8x57 30-06.

The original IMR4895 appeared in the 1930s, and was at least partially designed for the @150-grain load in the MI Garand. It was made by DuPont,as I recall at their plant in Wilmongton, Delaware. It burned most consistently at around what these days would be 50,000 PSI. This resulted in enough muzzle-pressure to run the operating rod of the M1 without harming it.

DuPont continued to make IM4895 throughout WWII, and after the war so much was on hand that the U.S. started selling off "war surplus" powder. Bruce Hodgdon bought a bunch, and started selling IMR4895 as Hodgdon H4895--along with a much slower-burning surplus powder he called Hodgdon H4831.

Because the mil-surp 4895 was so versatile and "affordable," handloaders used a bunch of it in various cartridges, which I believe is one reason I why so many post-war handloading writers advised for years that powder charges a little less than "maximum" tended to be more accurate.

After the mil-surp supply of 4895 ran out, it was made in various factories. One was the IMR factory in New York state, but for a quite a while it's been made in Quebec. In general, they were all based on the same formula, though it's changed somewhat since the 1930s. It still burns most consistently at around 50,000 PSI, which is why it works well in somewhat "reduced" loads, these days meaning pressures less than 60,000+ PSI--which is where many modern powders, especially slower-burning powders, are designed to do.

As I already mentioned, the present "H4895" is made in Australia, and is different from the original mil-surp H4895, being far more temperature resistant, and also burning more consistently at lower pressures.

I am most likely FOS. I'll be the first to admit I know zero about solid fuel physics or pressure/velocity math, I never even graduated from High School. You can change my mind(?) easily, I'm not religious about this, but I am more than willing to listen to reason and logic. But am I mistaken in thinking that with all things being the same, bullet, brass, primer, firearm,,,,, subbing CFE and BLC-2, grain for grain I get the same velocity, plus or minus 30 fps, I am pretty much using the same powder regardless of the label?

Someone else can fill in the details (or correct me if I'm off base on something), but the pressure curves for two different powders can be different shapes and produce the same velocity for a given identical charge weight. That is, the peak pressure could be rather different for two different powders and produce the same velocity. Newer instrumentation technology has enabled pressure testing labs to collect data during the very fast/short transients of pressure when ammo is fired in a rifle barrel, resulting in much better knowledge of the pressure curves for powders new and old. Bottom line is your chronograph can tell you something about pressure, but not everything.

I'll have to update my rifles on this development....

Because they are not experiencing the same results that Hodgdon's marketing dept are telling them they should be seeing...

no offense to anyone is intended here....neither me nor my rifles are seeing the same results as we are suppose to see.

Wise. They're a marketing company and basically incompetent at ballistics. If it wasn't for rebranding powders they don't really understand, they would have nothing to sell.

flintlocke,

BL-C(2) and CFE223 are not the same powders, though they obviously have very similar burn-rates.

BL-C(2) was originally a military surplus powder purchased by Hodgdon after WWII. Different batches had somewhat different burn rates, so Hodgdon gave the different batches different names. The original H335 was one of these.

All were relatively temperature-sensitive and dirty-burning, as most early spherical powders were. Eventually the mil-surp supply ran out, and Hodgdon had new powders made to approximate them. I know this because I got one of the new H335 batches in the early 1990s, and my long-time load in the .223 Remington had to be adjusted a grain or two to work like the old powder. But it was still relatively temperature-sensitive and left a lot of residue in the bore.

CFE223 is a new powder designed to be temperature-resistant, is cleaner-burning, and contains a decoppering agent. Haven't checked to see what that is, but most every other new decoppering powder uses bismuth.

Sorry about my other comment!

John