IMR Burn Rates

Ganderite

Ganderite

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Farm south of North Bay
I was looking up some IMR data from my records. Thius info may be of interest.

I have some of the EXPRO data sheets (Expro makes IMR brand powder.) They assign relative burning rates to powders, with 4350 being 100.



4227 180
4198 160
3031 135
4064 120
4895 115
4320 110
8506 108
4350 100
4831 94
7828 84
 
I always thought 4064 was a little slower than 4895 ( and of course a little faster than 4320). 4064 is my favourite powder. Burnt up more than 30 lbs since I started reloading. Mostly in 6.5x55, 308, 3006, 303 Br. 7.62x54 and 8x57.
 
Yes, I always thought 4064 was a bit slower, too. From the data sheets i can see that the two powders are the same, except for the grain size, making 4064 slower. i do not agree with their listing. but there it is.
 
Ganderite, do you have a listing anywhere for Expro 7900?
I have a 7 pounder that I got from Higginsons many years ago.
I believe it is close to IMR 4831.
Hope you can verify.
FWIW, I have several pounds of 8506 as well..really like it.
Eagleye.
 
Interesting that Expro says 4064 is slightly quicker than 4895.

I once pressure-tested IMR4895 and IMR4064 many years ago (at your place, Ganderite). The IMR4064 was slightly quicker (higher pressure than the IMR4895, for a given powder charge). My best explanation at the time, and which still may be valid, is that the only thing I measured was that *that* lot of IMR4064 was quicker than *that* lot of IMR4895.

It was my understanding that IMR4064 is cleaner than IMR4895. Perhaps this is just a difference in the amount of graphite they apply, but perhaps there are some small differences in the deterrents they use?
 
I have specs on IMR7900. It is a slow commercial powder (not sold in canister lots). The sheet does not show a burn rate, but judging by grain size and coating it would be in the 4831 range of slowness.

RNBRA - 4895 and 4064 appear to be made from the same dough and have the same deterrent coating (DNT). The difference is grain size. This is why I would think 4064 should be a bit slower. I recall having this same discussion with EXPRO and came to the same conclusion you did.
 
Ganderite said:
I was looking up some IMR data from my records. Thius info may be of interest.

I have some of the EXPRO data sheets (Expro makes IMR brand powder.) They assign relative burning rates to powders, with 4350 being 100.



4227 180
4198 160
3031 135
4064 120
4895 115
4320 110
8506 108
4350 100
4831 94
7828 84
Click to expand...

Thanks guy. Made a copy and stuck it in my reload file.
 
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