6-284 Stand Gun and a little 6BRX info

On a serious note, I do believe that I can recall in my cobwebs reading somewhere that IMR 4895 is used in military Firearms due to the fact that it is flameless after 16 inches, meaning it all burns up.

Probably wrong, but I use this burn rate as a baseline. Anything slower should require a longer barrel to burn. I'm sure bore diameter and case capacity has a lot to do with this also.

I hope this helps.

Joe
 
LightTheTower said:
So… how do we find out if a powder is degressive, neutral, or progressive?😳
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Gday Ltt
🤷‍♂️Over my head but equally like to know

@Bojo34 handling of the firearm takes precedent for me over worrying about a extra 50/100 fps
Take my 375 rum I’ve taken 5&1/2 inches off the latest barrel from the original
For me personally I still shot well enough with the longer barrel but it’s not in the same league as where it is now & more importantly my sons like it way better as it’s balance point has been improved

Looking forward to the smart ones shedding a little more light on this subject

Cheers
 
LightTheTower said:
So… how do we find out if a powder is degressive, neutral, or progressive?😳
Click to expand...
I found this on the subject: Reloading - different powder types

"An increase in form function is described as progressive (Tubular powder) and a decrease is degressive (flake and ball powder). Long tubular grains are usually quite neutral. The shape can have a marked performance on ballistics as progressive powders achieve good velocities at lower maximum pressures and vice versa for degressive powders."
 
LightTheTower said:
So… how do we find out if a powder is degressive, neutral, or progressive?😳
Click to expand...
Good question, I'm not sure. I just took it as an explanation of how powders achieve varying degrees of burn rate. I wouldn't be shocked to find out that this isn't the only way for the manufacturers to adjust burn rate, as seems to be implied in piece that @darkeagle10x found. After seeing the diagrams though certainly made a lot of sense to me even though never really thought about how the manufacturers achieve different burn rates. This piece I referenced was written in 1998 so manufacturing processes likely been refined since then.

I thought the pressure curves were particularly interesting. Prior to seeing those I just simplistically thought pressure was pressure and was more or less 1:1 correlated with velocity. To see that middle pressure curve chart that overlays the curve of a fast burner with the curve of a slow burner and indicates slower burning powders can achieve higher velocity with a lower peak pressure was eye opening. It seems to indicate that the highest velocity powder will be the slowest burner that achieves peak pressure farthest down the barrel? Maybe that's the real reason longer barrels are faster? Anyway, interesting but this stuff can make your hair hurt after a while.

@Farleg, thanks....100% agree!!
 
Bojo34 said:
Good question, I'm not sure. I just took it as an explanation of how powders achieve varying degrees of burn rate. I wouldn't be shocked to find out that this isn't the only way for the manufacturers to adjust burn rate, as seems to be implied in piece that @darkeagle10x found. After seeing the diagrams though certainly made a lot of sense to me even though never really thought about how the manufacturers achieve different burn rates. This piece I referenced was written in 1998 so manufacturing processes likely been refined since then.

I thought the pressure curves were particularly interesting. Prior to seeing those I just simplistically thought pressure was pressure and was more or less 1:1 correlated with velocity. To see that middle pressure curve chart that overlays the curve of a fast burner with the curve of a slow burner and indicates slower burning powders can achieve higher velocity with a lower peak pressure was eye opening. It seems to indicate that the highest velocity powder will be the slowest burner that achieves peak pressure farthest down the barrel? Maybe that's the real reason longer barrels are faster? Anyway, interesting but this stuff can make your hair hurt after a while.

@Farleg, thanks....100% agree!!
Click to expand...
Yes! I suspect this whole article actually explains why RL 26 is magic dust, but I can’t prove it.😉🤘
 
Cool! Towards the end of the black powder era there were significant developments being made in the performance of BP for various uses. A lot of experiments were done but one particular area was that of grain size and shape, (hexagonal, tubular, cylindrical etc.) they used these techniques to adjust the burn characteristics for different uses. No doubt others know more about this than I but it makes sense to me that those techniques would also work with nitro based powder.
 
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