Measuring case capacity, load density and picking a powder, let's say 30-06 to start

kilohertz

kilohertz

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Hi guys,

Started working up a load for my 30-06 and was using IMR 4350 and 150gr bullets, loading in my Dillon 550B, managed to get the starting loads just fine but when I got up to 56gr, my adjustment range was at its' max for powder discharge from the measure. Called Dillon and they said I could buy the magnum powder bar, $30USD and about $60CDN and 2 weeks by the time it gets here next month...so that won't work as I want to get the load figured out and ready for October hunting....so that got me thinking (which is sometimes a good thing :rolleyes:)

I went back to the load data and started looking at different powders that I could measure properly and that got me thinking and reviewing some basic principles of reloading, which brought me to case capacity and load density. Lyman's book states "quite often the best accuracy can be achieved with a 90% or greater case capacity". So my question is to the experienced loaders out there, what is considered 100% case capacity, is it loaded to the bottom of the neck, full to the top of the case, or ??? Also, what would be considered the difference between case capacity and "load density"? Some load data gives load density but does it directly relate to case capacity, or is load density measured against max CUP for that caliber, and of course varies with different powders? Also, different cases will have different thicknesses, and as a result, different volumes. And then there are the 3 different powder types, stick, ball and flake and each will have a different grain/cc or weight per volume and they pack differently.

As an example, 59gr of IMR4350 is the max load for 30-06 recommended by several listings (and may be a compressed load) but for only 100fps reduction one can load 50 gr of IMR 4064. The difference becomes even more dramatic on some of the smaller calibers I load for, 7X57 and 6.5X55 where say 37gr of one powder, will achieve the same velocity as 49 gr of another.

Maybe I'm overthinking this all and should just get out there and load and shoot, but I would at least like to start with an intelligent selection, and understand how and why to make that selection. I also don't want to wind up with a "powder museum" with many types that only get used for one rifle. I have picked what I think are good powders, which I have been able to buy locally, and should be replaceable. IMR 4064, 4350, 748, 760 and Varget.

Anyway, some guidance from the brain trust would be appreciated.

Thanks!
 
Get a scale, work up your load based on printed data... let the rifle tell you what it likes to shoot.

I used H4350 and 165gr Bullets in my 30-06 and every single rifle shot this weight well.

When you start shooting, you will have the answer to your question

And then more questions if you want to improve beyond hunting grade accuracy.

I would not use the Dillon for powder dispensing is you want any consistency in your loading.

Jerry
 
Your powder bar won't throw the max charge?

OK. Since this is for hunting with a 30-06, I would have suggested switching to a 180 gr bullet anyway. A 150 would be rather explosive on deer. A 180 just drops them without the pink mist. And A 180 works very well on moose.

And a 180 uses less powder, so your powder bar should work just fine.
 
Okay guys, thanks for the replies, and good suggestions. I stopped in at a friends business today (he is a bench rest shooter) and asked him the same questions, and he too suggested 4064, but I was more interested in knowing the whys of choosing a powder.

I would still like to know some of the answers to the above questions re: case capacity, load density etc., and how one really decides what powder would be best to start with (keeping my 550 limitations out of the equation). I know we can read the load data and get a number of loads that will "work", but when you can get the same velocity with 48gr of one powder, or 59gr of another....how do you choose? After years of your experience, how does one decide what to go with? Do you look for something that gives you more than 90% load density, do you look for max velocity, do you look for least amount of powder, a combination of the above? I know ultimately that the rifle will decide what it likes, but I am not looking for a load for this particular rifle, I just picked it as a common caliber to discuss, I am asking a question in general terms, in order to learn, how do you determine where to start? I have the 5 powders mentioned, and I do like shooting, but I don't want to randomly pick one and spend time and money trying different loads, only find out that I made an poor judgment in powder selection.

Thanks all.

BTW, for the 30-06 I will try the 180gr with 4064, and save the 150 and 165 for my Tikka M55 .308 :d
 
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Since all my guns are for hunting something, I look through the manuals to find a good load density that produces the best velocity and start testing with the bullet I want to use. A grain or two of powder "saving" is just silly. The cost saving is irrelevant when you compare it to the actual cost of shooting, if you do any real cost analysis of the hobby. I want a bullet I trust (or one I want to find out if I can trust) a powder that is "common" enough, the best velocity I can have with no "issues", and accuracy good enough to hunt the intended game. There is no way anyone can predict results from case capacity, charge weights, load density (although it is a valid generalization that good density is best) bullet maker or type, or anything else. The only genuine way to make decisions is after testing specific loads in your specific rifles. There are no reliable shortcuts around that fact.

So make your call and start testing.
 
Load density. With extruded (stick) powders not as big an issue, unless you are into something slower than 4831.

With ball powders, ignition is poorer with a low density charge. (Needs the magnum primer)

A 100% case would be full to the bottom of the neck area and the seated bullet would touch the powder. Shaking it produces no noise.

If the powder charge is below the shoulder, I would move to a slower powder.

If the case is full to the brim, I would look to go one step faster powder.

The loads in a manual are loads that "work". The load listed with the fastest and slowest powder may not be very good, but they work. A good manual will mention somewhere what one of the better powders choices is.

Your 4064 is the optimum powder for the 150 bullet. For the 180 I would use 4350.
 
In the Lee Modern Reloading manual each charge has the volume in cubic centimeters.

1 cubic centimeter = 1000 cubic milimeters = 1gram (water) = 15.432grains water

You can compare this with the water case capacity (substracting the neck volume which is not difficult to calculate: volume = L*PI*D*D/4 where L is the neck length in mm, PI is 3.1415, D is the bullet diameter in mm)
 
for IMR4064 the pressure does change significantly with the temp.
...and yes you should be using magnum primers in very cold temperatures...
 
This ground has been walked many times before. For a 150 or 165gr bullet in the .30-06 it's IMR4064, IMR4895 or Varget with a nod to IMR4064. For a 180gr bullet its IMR4350, done and finished. No need for magnum primers, but they don't hurt.
 
purple said:
This ground has been walked many times before. For a 150 or 165gr bullet in the .30-06 it's IMR4064, IMR4895 or Varget with a nod to IMR4064. For a 180gr bullet its IMR4350, done and finished. No need for magnum primers, but they don't hurt.
Click to expand...

in -20ºC magnum primers are a must.
 
legi0n said:
for IMR4064 the pressure does change significantly with the temp.
...and yes you should be using magnum primers in very cold temperatures...
Click to expand...

This is probably in the data sheets somewhere, but since I have your ear..if I make a load that works great at 20C, if the temp drops to -10, and the same round is fired, will the pressure be higher or lower? And of course, velocity and POI will change too.

thx
 
In choosing a powder, your rifle may prefer one powder over another, (accuracy). A lot of this must be done by the trial and error method. For a good flat shooting rifle for hunting purposes most people want a powder that will give high velocity. A bit of research and you will find the most popular powders for a certain caliber. I like the Nosler online data as it shows the most accurate load that they found in their testing which sometimes may work out for your rifle. I found their 30-06, 180 grain accurate load with 60 grains of H4831 worked great in my rifle. And yeah, you might be over thinking this a bit.
 
Ganderite said:
Your powder bar won't throw the max charge?

OK. Since this is for hunting with a 30-06, I would have suggested switching to a 180 gr bullet anyway. A 150 would be rather explosive on deer. A 180 just drops them without the pink mist. And A 180 works very well on moose.

And a 180 uses less powder, so your powder bar should work just fine.
Click to expand...

Of course, if a fella chooses NOT to run them just as fast as they can go, they don't blow up near as much.

A hunting bud shot a small doe from 30 yds or so with a 180 outta his 300 Win Mag, and the poor thing had a bloodshot ring around the bullet hole that was over a foot across. Speed, not weight, gets you the mess, IMO.

Cheers
Trev
 
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