Do you see equal charge weights with different powders yield the same velocity?

[josh.rizzo]

I was experimenting with different powders in 223REM and found that most powders yielded the same velocities with the same charge weights. For example, 26 grains of either TAC, IMR 4320, Varget, or Norma 202 all yielded about 3050fps with a 55gr pill in a 16" 1:9 twist barrel.

Now, some powders would not get to that weight before seeing pressure signs. For instance, Benchmark saw pressure signs well before I worked up to 26 grains. And all of them took up different amounts of case capacity. So I'm not arguing that all powders are the same by any means, but rather that most powders seem to contain the same amount of total energy per weight.

Has anyone else seen similar or different results?

 

[rocknut]

I tend to disagree. I have used numerous different powders and they all differ in the amount of energy they contain and how long they take to release that energy. I shoot mostly .308. I started to get flattened primers with 42 grains of IMR 3031. On the other end of the powders I use, I can use 46.5 grains of PP2000 or CFE 223 and show no pressure signs at all. There are a lot of powders that are very similar; IMR4320, Varget, IMR4895. But I can't see how you would get the same velocities out of the same charge weight.

 

[stool]

i use pills for my blood pressure and bullets for my rifles...

several powders are designed to do the same thing, some are actually the same powder....so it is not surprising to see similar velocities.
now is the rifle shooting the same with each ? is it the same after each(how much crud in the bore) ?

 

[josh.rizzo]

OK, good to hear it was just unique to my experiences. Obviously some powders are functionally close, but it indeed would not make sense if they were ALL the same. Hence the reason I asked the question.

now is the rifle shooting the same with each ? is it the same after each(how much crud in the bore) ?

In my case, all the loads that I could get to the same velocity seemed to group the same. So here is a follow-up question: Does anyone notice that a rifle groups the same, regardless of powder, as long as the load shoots at the same velocity (assuming there is no difference in velocity spreads)? Or is my .223 rifle just not very picky?

 

[1shot]

I had a 6.5x47L that shot the same velocities with both N-140 and N-150 behind a 123 or 130 gr. bullet. However, the accuracy and extreme spread went to the N-140. I, like the OP had never experienced this before but I chalked it up to "just one of those things" and moved on. No, it certainly not common, but it does happen.
I hope this helps,
Lloyd

 

[4xforfun]

No.