H-series of powders vrs IMR

[gtl1946]

I notice in a lot of cartridges a lot of shooters are using the H - series of powders over IMR or AA . Why? I'm looking for H-4350 for the 30-06 and can't find it . I can use other powders I have on hand but as you may know H-4350 is a powder of choice . Am I making a mountain out of a molehill or do I get the other series go with them . IS THERE A VERY GOOD REASON TO WAIT TO TRY THE H-SERIES ????

 

[1lnbrdg]

H-series Extreme powders kind of set the bar due to their temp insensitivity qualities. To further complicate the question, some of the IMR powders are now considered temp insensitive too.

Temp insensitive is a relative term, they are all susceptible to temp variations, just some less than others.

Some of the powders that are not in the "Extreme temp insensitive" group have worked for years though without major issues.

 

[Laurie]

There's a lot of history here. IMR was the norm in the US for many years as developed and manufactured by the Dupont Corporation. Many of the IMR range predate WW2. Post WW2, B.E. (Bruce) Hodgdon bought up large quantities of military surplus IMR powders and sold it repackaged with information on that individual production lots burning rate characteristics. The primary grades were 4895 and 4831, the former used in .30-06 Ball M2 and the latter in 20mm cannon ammunition.

When that source dried up, Hodgdon didn't intend to pack up and find a new trade, rather went around the world looking for new sources - initially ICI Nobel in Scotland and later when it closed down, ADI in New South Wales, Australia. These companies didn't make bespoke tailored versions, rather whatever was closest to IMR-4350 say was renamed H4350 and new loading data published. So, today's H4350 is the third iteration of the product while the original IMR has remained at the same energy and chemical characteristics spec. Throw in another complication in that Hodgdon's original IMR manufactured surplus 4831 lasted a long, long time ..... and slowly changed characteristics during storage becoming slower burning. When the surplus stuff eventually ran out, the customers wanted the 'Hodgdon' version to continue, not revert to faster burning new made IMR spec, so Hodgdon sourced a slower burner from ICI then ADI.

ADI / Thales is one of the most innovative and dynamic manufacturers of smallarms propellants worldwide and has improved its products remarkably in recent years as well as vastly extending the range of grades. The single biggest advance was the 'Extreme' characteristics given to all extruded grades, but every aspect was looked at and imnproived if necessary, a good example being the moved to 'short-cut' grains for better charge densities and more accurate metering in traditional powder measures. The combination of such enhancement, lots of fine gradations in energy content / burning rates across the range, very consistent and high-spec products allied to the 'Extreme' insensitivity to temperature change was much appreciated by the customers, and product / brand loyalty enhanced by Hodgdon's mix of excellent load data, marketing and sponsorship work. IMR meanwhile suffered as Dupont was broken up and production moved elsewhere, but is now finally catching up and under General Dynamics ownership is introducing a new range of 'Enduron' temperature insensitive / copper fouling eraser grades. Although helped by Hodgdon being the information / data producer and marketing / distributing organisation for handloading canister grades, it has long way to go to gain the same degree of customer trust and appreciation.

So far as H4350 and shortages goes, IMR-4350 may or may not be a good stand-in, but the new 'Enduron' IMR-4451 certainly is. It's marginally slower burning, but is an excellent alternative to the H version in cartridges like 260 Rem and 6.5mm Hornady Creedmoor. I'd imagine .30-06 too, although it's a long time since I last loaded this one. (Talking .30-06, it's the old IMR version of 4350 that is the 'classic' powder for this cartridge with 165-180s and the upstart H version is the interloper!)

 

[Deton8tor]

I shoot IMR4350 in my '06 near a max load and it is a pure hammer for me. Stock Remington Boone N Crocket '06. 165 AB's shoot very well. I also ran IMR 4350 in my .300 win with 190 SMK's and it was a hammer. I loaded them for hot weather 85-95 temp and have not had a problem. I did some shooting in 23 degrees with the same load and had to come up .7 mils to get back to POI from the hot weather load. Other than that I have NEVER had an issue with IMR 4350. That said, I loaded some IMR4451 in a 6.5 Creedmoor and it is shooting lights out too. It is a tad slower than the H stuff. but gets the job done nicely.

 

[gtl1946]

I shoot IMR4350 in my '06 near a max load and it is a pure hammer for me. Stock Remington Boone N Crocket '06. 165 AB's shoot very well. I also ran IMR 4350 in my .300 win with 190 SMK's and it was a hammer. I loaded them for hot weather 85-95 temp and have not had a problem. I did some shooting in 23 degrees with the same load and had to come up .7 mils to get back to POI from the hot weather load. Other than that I have NEVER had an issue with IMR 4350. That said, I loaded some IMR4451 in a 6.5 Creedmoor and it is shooting lights out too. It is a tad slower than the H stuff. but gets the job done nicely.

I can't thank you gentlemen enough for taking the time to answer the question I asked,and especially to you Laurie for your thoughts and the "history lesson ". Much appreciated!!
The IMR tech recommended IMR 4451 for the 168grn and up bullets I'm loading now in my bolt action 30-06's . I'm wondering if that powder will end up being suitable in other cases for substituting for H4350 ???

 

[stacy]

ALOT OF GUYS ARE USING IMR 4451 IN PLACE OF H-4350 IN 6.5X47 AND 6.5 CREEDMOR'S

 

[gtl1946]

ALOT OF GUYS ARE USING IMR 4451 IN PLACE OF H-4350 IN 6.5X47 AND 6.5 CREEDMOR'S

That's the other thing I'm going to be looking at- what else can you use this for? Is this going to be IMR's "accuracy " equivalent to H-4350???

 

[rardoin]

That's the other thing I'm going to be looking at- what else can you use this for? Is this going to be IMR's "accuracy " equivalent to H-4350???

I have several reports of IMR-4451 being as accurate and producing equivalent velocities in the smaller case capacity 6.5 Creedmoor, just requiring about one grain more than the H-4350 loads. I found good accuracy in my Creedmoor but I had to compress the loads more than I desired in a Lapua case to get the velocity of 4350. Note- I have a fairly slow barrel as I have to use more powder of any variety to achieve velocities that most others get with standard loads. In a larger case such as a .270 or .30-'06, the 'extra' 4451 required should be of little issue unless you are loading at max loads/near 100% capacity already. I think it will pan out to be the "IMR accuracy equivalent of H4350".

 

[savagedasher]

I have several reports of IMR-4451 being as accurate and producing equivalent velocities in the smaller case capacity 6.5 Creedmoor, just requiring about one grain more than the H-4350 loads. I found good accuracy in my Creedmoor but I had to compress the loads more than I desired in a Lapua case to get the velocity of 4350. Note- I have a fairly slow barrel as I have to use more powder of any variety to achieve velocities that most others get with standard loads. In a larger case such as a .270 or .30-'06, the 'extra' 4451 required should be of little issue unless you are loading at max loads/near 100% capacity already. I think it will pan out to be the "IMR accuracy equivalent of H4350".

IMR shoots great if it stays cool . Don't leave it in a hot chamber . Larry

 

[rardoin]

IMR shoots great if it stays cool . Don't leave it in a hot chamber . Larry

Please expound on this statement. In my limited experience with 4451, I did a crude test of rounds at 100% capacity ( or slightly above that ) for velocity increase/pressure signs by letting rounds cook in a hot chamber for several minutes and did not see any change in velocity that could be attributed to temperature. I have done this with another very accurate powder in that rifle (H 100V hybrid) and i got significant velocity increases and primer flattening. I find 4451 to be relatively temperature insensitive.