westernrover
Member
- Joined
- May 4, 2018
- Messages
- 1,613
I'm considering powders for 223. My choice will be dependent upon the bullet which I hope to decide upon next week (some boxes are coming in). In selecting a powder, I've noticed the slower burn rate powders like CFE223, BL-C, and StaBall Match produce the highest velocities in some published data, but not consistently. I would expect powders that take more bullet travel before reaching peak pressure to maintain higher levels of pressure behind the bullet for longer and achieve greater muzzle velocities. I would also expect this of powders that have secondary pressure peaks like CFE223. That is reflected in Hodgdon's published data and also in Barnes, but some results have been contrary. Lehigh's load data does not show a significant difference for max loads between CFE223 and Accurate LT-32 -- a much faster powder. The results in the following video also demonstrated some results very different than published data in that some powders where the published data promised higher velocities than other powders simply did not deliver.
Maximum velocity is not my goal, though I think velocity is meaningful to terminal performance with this cartridge at the shorter ranges it is most likely to be employed through a semi-automatic modern sporting rifle.
I am not using it in a bolt gun or for benchrest or varmints. Accuracy is also meaningful, but I won't be chasing quarter-MOA vs. half-MOA or anything like that. Some might conclude that given performance requirements that aren't extreme, there would be little to differentiate powders.
Cost is considerable, but I don't need the cheapest powder. TAC is relatively inexpensive right now at $219 for 8 pounds. Varget might cost as much as $350 for 8 pounds. That difference of $130 works out to about 6 cents per round -- meaningful, but not decisive.
Barnes indicates the "most accurate" results for particular bullets from powders in their load data. While their choices don't have perfect inverse correlation between bullet weight and burn rate, they generally follow that trend. That also seems to be the conventional wisdom or consensus I've read in researching the question on forums -- powders like H335 tend to be favorites for 55 grain bullets, whereas slower powders like CFE223 are not likely to be favored except with bullets 77 grains and heavier. Powders with burn rates in the middle of the range for the cartridge like TAC tend to be favored for middle-weight bullets, 62 to 69 grains.
Why is that?
I understand that much too slow powders need a larger case to fit sufficient volume to produce the necessary pressure. Excessively fast powders will simply reach peak pressure with an insufficient volume of powder to maintain pressure behind the bullet for long enough to develop good velocity.
Within the viable burn rate range for 223, say from LT-32 to CFE223, why do slower more progressive powders not work well with light bullets? Is it because lacking inertia they move down the bore too readily and the combustion fails to develop sufficient pressure to burn consistently?
Has anyone quantified the effect of this? If I select a faster powder with a 55 grain bullet, I might be giving up two or three hundred fps in muzzle velocity compared to one of the slowest powders. How high a price do I pay in SD/ES or accuracy?
Maximum velocity is not my goal, though I think velocity is meaningful to terminal performance with this cartridge at the shorter ranges it is most likely to be employed through a semi-automatic modern sporting rifle.
I am not using it in a bolt gun or for benchrest or varmints. Accuracy is also meaningful, but I won't be chasing quarter-MOA vs. half-MOA or anything like that. Some might conclude that given performance requirements that aren't extreme, there would be little to differentiate powders.
Cost is considerable, but I don't need the cheapest powder. TAC is relatively inexpensive right now at $219 for 8 pounds. Varget might cost as much as $350 for 8 pounds. That difference of $130 works out to about 6 cents per round -- meaningful, but not decisive.
Barnes indicates the "most accurate" results for particular bullets from powders in their load data. While their choices don't have perfect inverse correlation between bullet weight and burn rate, they generally follow that trend. That also seems to be the conventional wisdom or consensus I've read in researching the question on forums -- powders like H335 tend to be favorites for 55 grain bullets, whereas slower powders like CFE223 are not likely to be favored except with bullets 77 grains and heavier. Powders with burn rates in the middle of the range for the cartridge like TAC tend to be favored for middle-weight bullets, 62 to 69 grains.
Why is that?
I understand that much too slow powders need a larger case to fit sufficient volume to produce the necessary pressure. Excessively fast powders will simply reach peak pressure with an insufficient volume of powder to maintain pressure behind the bullet for long enough to develop good velocity.
Within the viable burn rate range for 223, say from LT-32 to CFE223, why do slower more progressive powders not work well with light bullets? Is it because lacking inertia they move down the bore too readily and the combustion fails to develop sufficient pressure to burn consistently?
Has anyone quantified the effect of this? If I select a faster powder with a 55 grain bullet, I might be giving up two or three hundred fps in muzzle velocity compared to one of the slowest powders. How high a price do I pay in SD/ES or accuracy?
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