Powder Interchangability?

Qtiphky · February 6, 2009, 07:00 PM

In looking through my Sierra reloading manual, I can't get a clear answer to this question. Is H 4895 interchangeable with IMR 4895? I have seen several recipes in which the IMR was used, but I currently only have H 4895. I was on Hodgdon's website and e-mailed them but haven't been able to make a determination.

Any help would be appreciated.

Wildalaska · February 6, 2009, 07:11 PM

they are NOT interchangeable

WildnononoAlaska ™

BigJimP · February 6, 2009, 07:48 PM

No, they are not the same powder.

TonyAR308 · February 6, 2009, 10:22 PM

What is the difference besides manufacturers?

Sevens · February 6, 2009, 10:29 PM

They are not interchangeable, meaning, they are NOT the same powder.

If you build a load in a caliber that eats 34.5 grains of IMR-4895, you'd be a fool to pour 34.5 grains of H4895 in there without checking published load data in your caliber for H4895.

However, they are certainly close enough that anything you can use in, you can use the other. But they aren't the same and shouldn't be looked at as if they are the same.

What is the difference? You'd have to contact Hodgdon, since they now market both powders, and ask them the difference.

Hammack · February 6, 2009, 10:34 PM

H4895 is slightly faster than IMR 4895. Here is a chart that shows the burn rate of most common powders. http://www.reloadbench.com/burn.html

bigalshootmupper · February 6, 2009, 11:06 PM

Hammock, that burn rate chart may be a little out of date. The 4895 rate may be accurate but I checked the Winchester 748 and it shows it as a tad bit faster than the 4895 powders (11 spots faster), but the latest Hodgdon manual I have has the Win 748 a tad slower (11 spots slower).

Goes to show that you should never assume anything, and start at least 10% lower than what a trusted manual says. Each lot varies and manufactures may change the powder without notice. New lot - start over at minus 10%.

**Unclenick** · February 6, 2009, 11:37 PM

If you look at a dozen burn rate charts you find a dozen different powder orderings unless one has been copied from the other. The manufacturers keep the exact nominal burn rates for their products proprietary. Since they don't share, the charts are all educated guesses. Good enough to help you choose a range of powders but not exact. Moreover, the burn rates vary a little from lot to lot. The manufacturers try to adjust them to produce fairly constant charges from one lot to the next, but they don't do an exact job of it. So powders will change position on an accurate burn rate chart (if there were one) from time to time.

Burn rate is also of limited value. It's a ballpark estimating tool and a tool for the makers to match one lot of the same formulation to the next. It isn't nearly so useful comparing between formulations. Burn rate is measured by burning a quantity of powder in a caloric bomb at a standard regulated pressure that is kept constant. The result is in liters of powder burned per second. But the ranking often only holds true at that one test pressure. The powders have different progressivity rates (change in burning rate with change in temperature and pressure and completeness of grain consumption). Thus, you could work up loads at one pressure at which one powder was faster than another, only to have the title of fastest powder reversed at some other pressure you worked another load up to with them.

H4895 and IMR4895 are meant to be similarish. H4895 is part of the Hodgdon Extreme powder line. It has different burning rate retardants, being designed to have an especially constant burning rate over a wide temperature range. So, if it doesn't have the same burn rate at one temperature it might at another. About the most you can say is that if IMR 4895 is a good powder for, say, a 165 grain bullet in .30-06, then H4895 will also be a good powder for a 165 grain bullet in .30-06. The achievable muzzle velocity won't be hugely different at maximum loads of either. But the charges won't be the same.

TEDDY · February 7, 2009, 07:59 PM

I just looked at that chart what a mess 173 different powders.its like the congress every one different.no wonder its confusing.

Scorch · February 8, 2009, 12:36 AM

Quote:

The 4895 rate may be accurate but I checked the Winchester 748 and it shows it as a tad bit faster than the 4895 powders (11 spots faster), but the latest Hodgdon manual I have has the Win 748 a tad slower (11 spots slower).

That ranking is purely arbitrary when dealing with powders that have the same burn rate. If two powders have the same burn rate, what difference does it make which one is listed first, right? But even though the powders may have the same burn rate, the same grain size, the same appearance, the same manufacturer, that does not make them interchangeable because they probably do not have the same density (weight per volume), so interchanging them could cause a dangerous overload condition.

February 6, 2009, 07:00 PM	#1
Qtiphky Senior Member Join Date: December 11, 2008 Location: Upper Michigan, above the Mackinac Bridge Posts: 568	Powder Interchangability? In looking through my Sierra reloading manual, I can't get a clear answer to this question. Is H 4895 interchangeable with IMR 4895? I have seen several recipes in which the IMR was used, but I currently only have H 4895. I was on Hodgdon's website and e-mailed them but haven't been able to make a determination. Any help would be appreciated.

February 6, 2009, 10:29 PM	#5
Sevens Senior Member Join Date: July 28, 2007 Location: Ohio Posts: 11,756	They are not interchangeable, meaning, they are NOT the same powder. If you build a load in a caliber that eats 34.5 grains of IMR-4895, you'd be a fool to pour 34.5 grains of H4895 in there without checking published load data in your caliber for H4895. However, they are certainly close enough that anything you can use in, you can use the other. But they aren't the same and shouldn't be looked at as if they are the same. What is the difference? You'd have to contact Hodgdon, since they now market both powders, and ask them the difference. __________________ *Attention Brass rats and other reloaders:* I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.

February 6, 2009, 11:37 PM	#8
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	If you look at a dozen burn rate charts you find a dozen different powder orderings unless one has been copied from the other. The manufacturers keep the exact nominal burn rates for their products proprietary. Since they don't share, the charts are all educated guesses. Good enough to help you choose a range of powders but not exact. Moreover, the burn rates vary a little from lot to lot. The manufacturers try to adjust them to produce fairly constant charges from one lot to the next, but they don't do an exact job of it. So powders will change position on an accurate burn rate chart (if there were one) from time to time. Burn rate is also of limited value. It's a ballpark estimating tool and a tool for the makers to match one lot of the same formulation to the next. It isn't nearly so useful comparing between formulations. Burn rate is measured by burning a quantity of powder in a caloric bomb at a standard regulated pressure that is kept constant. The result is in liters of powder burned per second. But the ranking often only holds true at that one test pressure. The powders have different progressivity rates (change in burning rate with change in temperature and pressure and completeness of grain consumption). Thus, you could work up loads at one pressure at which one powder was faster than another, only to have the title of fastest powder reversed at some other pressure you worked another load up to with them. H4895 and IMR4895 are meant to be similarish. H4895 is part of the Hodgdon Extreme powder line. It has different burning rate retardants, being designed to have an especially constant burning rate over a wide temperature range. So, if it doesn't have the same burn rate at one temperature it might at another. About the most you can say is that if IMR 4895 is a good powder for, say, a 165 grain bullet in .30-06, then H4895 will also be a good powder for a 165 grain bullet in .30-06. The achievable muzzle velocity won't be hugely different at maximum loads of either. But the charges won't be the same. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

February 7, 2009, 07:59 PM	#9
TEDDY Junior member Join Date: December 10, 2006 Location: MANNING SC Posts: 837	powders I just looked at that chart what a mess 173 different powders.its like the congress every one different.no wonder its confusing.

February 6, 2009, 07:11 PM	#2
Wildalaska Junior member Join Date: November 25, 2002 Location: In my own little weird world in Anchorage, Alaska Posts: 14,172	they are NOT interchangeable WildnononoAlaska ™

February 6, 2009, 07:48 PM	#3
BigJimP Senior Member Join Date: February 23, 2005 Posts: 13,195	No, they are not the same powder.

February 6, 2009, 10:22 PM	#4
TonyAR308 Senior Member Join Date: December 24, 2008 Location: Southwest Virginia Posts: 102	What is the difference besides manufacturers?

February 6, 2009, 10:34 PM	#6
Hammack Member Join Date: January 29, 2009 Posts: 17	H4895 is slightly faster than IMR 4895. Here is a chart that shows the burn rate of most common powders. http://www.reloadbench.com/burn.html

February 6, 2009, 11:06 PM	#7
bigalshootmupper Senior Member Join Date: November 21, 2008 Location: Georgia Posts: 147	Hammock, that burn rate chart may be a little out of date. The 4895 rate may be accurate but I checked the Winchester 748 and it shows it as a tad bit faster than the 4895 powders (11 spots faster), but the latest Hodgdon manual I have has the Win 748 a tad slower (11 spots slower). Goes to show that you should never assume anything, and start at least 10% lower than what a trusted manual says. Each lot varies and manufactures may change the powder without notice. New lot - start over at minus 10%.