Can this be correct?

Rocky7

Rocky7

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Nosler Reloading Guide, 7 ed. lists the following maximum charges for 264 Win Mag with 120 gr bullets:

R22 62.5 gr.
R19 64.0 gr.

R19 is the faster propellant. How come I can stuff more of it into the same case as compared to R22, the slower powder?

Am I having a brain fart or is the manual wrong?
 
stubblejumper said:
I am thinking that he meant that he didn't understand why the manual lists a heavier maximum charge for the faster powder. I find it odd as well.
Click to expand...

That's exactly what he meant.

I've been reloading for 30+ years and can't recall seeing this before. Maybe I just didn't notice, but as I am in the midst of working up a load for my .264 I thought somebody might be able to shed some light on it.
 
thump_rrr said:
Did you ever consider the powder manufacturer's website?
Once again they show 1 grain more of R19 than R22 albeit a much lower charge than Nosler.
http://www.alliantpowder.com/reloaders/recipedetail.aspx?gtypeid=2&weight=120&shellid=66&bulletid=115
Click to expand...

^^^ This

I always check at least two manuals but usually expand it to two manuals and a couple internet resources.
That does seem strange but shouldn't make much difference in the big picture since you should always start lower than the published maximum anyway.
Perhaps an email to the powder manufacturer for an explanation? I had a question for Hornady when I was trying to duplicate their 325FTX load for my 45-70 and they were surprisingly quick to respond.

Good luck
 
I think the OP is referring to the burning rates of the powder. R19 is faster than R22 and to see a manual list more of the faster powder than the slower powder for a maximum charge goes totally against the current. It's either an error or an anomaly.

Go onto the powder manufacturer's website and check it out by going to their home page and contacting them with an information request. Alliant is very quick to respond. Usually within a couple of days.
 
Actually, over the years, I have seen this phenomenon a few times,

Powders do act differently in different cases. Logic says that you would always use less of
a slightly faster powder with any given bullet and cartridge.

But we have some seemingly illogical things that appear from time to time.
There is a very small difference in the burning rates of RL 19 and RL 22, in my experience.

Regards, Dave.
 
Published burn rate is based on prescribed laboratory conditions that don't always replicate themselves in specific circumstances, chamber, bullet, bore/capacity ratio? So powders will behave differently in conditions that are different from how burn rate is determined. Some powders may tend to spike drastically under certain conditions, even if it has a 'slower burn rate', so published max load needs to account for that; if a spike takes the pressure over dangerous max, then the load needs to be reduced so that spike pressure is never surpassed.

...I could be pullin' this out of me arse for all I know.
 
There have been some significant variations from lot to lot with Alliant powders. so a slow lot of R-19, and a fast lot of R-22, is one possible explanation.
 
Well, as you're all stumped, too, I am not feeling stupid.

Yeah, I dunno. It might have something to do with the geometry of the .300 H&H line of cases but that's a stretch for me. I don't how that could make the pressure created by a given amount of slower powder burning inside the same chamber/barrel exceed the same (higher, actually) amount of a faster powder. Maybe somebody will come along who can clear up this poser. Meantime, I'm only building a ladder test at this point and I have an excellent bullet puller if the top end shows pressure so away we go.....

Eageleye, it seems that way to me, too, and yet R22 and R19 are not exactly next-door on a Burning Rate Chart. I've never had much use for R22 but it seems like it could be good for a .264 with a 26" bbl so I'm going to try 'er out.
 
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I always check a minimum of two manuals. The date of the manuals and age of the powder may also be factors. Older manuals often list much hotter loads than current manuals. And powder manufacturers have been known to change or tweak powders over the course of their life.
 
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