Can someone explain this... odd load data?

[ngnrd]

So, I've decided to load up a batch of 30-06 using RL-22 behind 180gr Nosler Partitions. It's a combination I haven't tried before, so I dutifully looked up load data in each of the references I have on hand.

Between Lyman 49, Alliant's on line reloading guide, and my two Nosler books, I've checked and cross checked the data for this combo and come up with a good range of powder charges. So, no problem there...

But, I did find something pretty odd. Nosler #6 shows 61gr of RL-22 to be a 114% compressed load, while Nosler #7 shows 62gr to only be a 105% compressed load. What the...? I'm no genius, but if you put more powder into a case, wouldn't that make the load more compressed? Or am I missing something here?

I will say that the Nosler #7 book has more information about the test loads than the #6 version, like tested COAL and case type. But, is there enough of a difference between cases to make that much of a difference in capacity? That's the only thing I could think of that would change the fill rate, unless maybe the bulk density of RL-22 powder has changed significantly.

What say you?

 

[rcmodel]

Check the case brands & bullet shapes used in each manual.

For what it's worth.
Alliant says 62.0 grain Max is a compressed load with a Speer 180 SP in a Winchester case.

rc

 

[USSR]

Don't know, ngnrd, but I wouldn't sweat it. I have found that a full case of RL-22 with a heavy bullet in a .30-06 give you more velocity than any other powder will. My load of 61.7gr give me 2900fps with a 190gr Sierra MatchKing.

Don

 

[ngnrd]

rcmodel: Both Nosler manuals use Nosler brass with this particular load, which is why I thought there may have been a change in bulk density of the RL-22.

USSR: Thanks for the info. I've loaded a set from 58 to 62 grains. I'm hoping I can find a good accuracy node with this combination around 2800fps.

 

[JimKirk]

Method of powder dropping into the case ....also has impact on how compacted powder will be ....

A short powder drop tube will not compact as well as will a longer tube ..

Also if the powder is just poured into the funnel verses letting the powder swirl the sides of the funnel will impact how compacted the powder is ...

That box of cornflakes was probably close to full when it was dropped into the bag ...but by the time it is shaken on the way to your table ... it is only 2/3 full at best....maybe 3/5!

 

[gamestalker]

Often times the variance will be due to different bullets, and, or, different brass, probably more so the latter.

As for RL22, it has become my go to powder for 7mm RM, 30-06, .270 win, and now I'm giving it a try in 6mm Rem., we'll see how that goes. Prior to going with RL22, I tried IMR-4350, H1000, RL19, IMR-4831 and a few others and had settled on IMR-4350 or RL19 for the 30-06 and .270 win.. Those powders produced great results in terms of accuracy, but there is just something about RL22 burn rate that keeps pressures very manageable, even when working up to the maximum published charges.

FYI, RL22 performs far better with magnum primers, I've tried standard primers with it, and it doesn't do well at all. Velocities and pressures were very erratic, accuracy was poor also. And most of the data I've looked at specifies a magnum primer as well.
GS

 

[Kerf]

Case volume...

Case volumes vary from manufacturer to manufacturer. Even by case lot #s. Even cases that are identical in weight and size can vary considerably in volume- say 3-4%. It’s always a good idea to check your lot #s and your case volumes when starting with a new batch of brass. (just something else you have to do).

kerf

 

[steve4102]

I asked Nosler about this a few months ago. I don't remember their exact response , but it had something to do with a new(different) way of calculating load density.

 

[ngnrd]

Thanks, Steve. That's what I was looking for.

 

[mookiie]

I was wondering if OAL for the cartridges differed maybe?

 

[ngnrd]

It's possible. The Nosler #6 book doesn't specify loaded length, so there's no way to tell by the data given.