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Different powder burn rates

meatyrem

meatyrem

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Came across something I been wondering about. Certain powders arranged in different places on burn rate charts. The particular one in question is N560. On one of the burn rate charts it's placed just below (slower) than H4831 and above IMR 4955 (hodgdons reloading manual) and on another it's placed between MRP2 and R23. Pics to be included. I believe the first one that's color coded is also from hodgdons site as is the second directly from manual. I know this is splitting hairs seems a little odd to me to have N560 in a faster burn on one and a slower burn on a different publication. Can someone shed some light on this maybe with a definitive answer. Does qucikload have burn rates published too?
 

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Two things come into play here:

First, burn rate charts show the RELATIVE burn rate. Figures are not exact. You should not use burn rate charts as an Absolute value when selecting a powder.

Second, there is no industry standard for establishing burn rate. If you look at 3 different manufacturer's burn rate charts, it is not uncommon to see some powders placed in a different order.

Charts are only useful as a Relative guide.
 
One enormous problem with burn rate charts.
No powder is rated to a single datum, each manufacturer rates their own powder in a RQ (Relative Quickness) list based on THEIR datum.
So, IMR lists IMR4895 RQ100, then faster powders are listed with HIGHER numbers, slower powders with lower numbers.
Hodgdon lists H4895 RQ100 and the same occurs, but neither of these powders burn at the same rate.
Now, every manufacturer rates THEIR RQ ratings based on RQ100 being the 'datum', but no comparison has EVER been made to see exactly if RQ100 with one manufacturer is the same START POINT for everyone else. There could be 10 points difference between RQ numbers even before the datum point was used.
Burn rates are NOT CONSTANT, they are NOT transferable between Burn Rate lists and should be considered a GUESS AT BEST.

Cheers.
 
Last edited:
MagnumManiac said:
One enormous problem with burn rate charts.
No powder is rated to a single datum, each manufacturer rates their own powder in a RQ (Relative Quickness) list based on THEIR datum.
So, IMR lists IMR4895 RQ100, then faster powders are listed with HIGHER numbers, slower powders with lower numbers.
Hodgdon lists H4895 RQ100 and the same occurs, but neither of these powders burn at the same rate.
Now, every manufacturer rates their publishes THEIR RQ ratings based on RQ100 being the 'datum', but no comparison has EVER been made to see exactly if RQ100 with one manufacturer is the same START POINT for everyone else. There could be 10 points difference between RQ numbers even before the datum point was used.
Burn rates are NOT CONSTANT, they are NOT transferable between Burn Rate lists and should be considered a GUESS AT BEST.

Cheers.
Click to expand...
That is precisely my point in #5.
 

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