Ball powders?

[jpuke]

I went to the range today and I lit off a bunch of .308 Win loads made with Win 748 and I noticed that the cases were coming out pretty messy - a lot of soot and I'm wondering if it's the powder or the cast bullets that I've been shooting.  (Maybe there wasn't enought pressure to get a good gas seal)  On Tuesday I shot a bunch of other loads that had IMR 4350 behind them and I didn't notice mess.  The smoke from the 748 also seemed to be a lot thicker versus the IMR which didn't seem to have any puff of smoke after my shot.  I was watching "Tales of the Gun" on the History Channel a few months ago and when they were talking about the M16 they said the switch from stick to ball powders (combined with the jungle climate of Vietnam) caused the rifles to gum up quicker - any truth to this?  I'm fairly new to reloading and my experience with different kinds of powders is limited.

[Nobade]

You likely weren't generating enough pressure to get 748 to burn properly. It is not a very good choice for reduced pressure cast bullet loads, as you have discovered. If you ran those loads over a chronograph I'd bet you would see some pretty big velocity variations. Some powders work well over a wide pressure range, and some don't. One of the best for rifle loads is IMR 4895; it'll burn clean down to about 60% of max and usually give good accuracy. Most ball powders work best at full throttle, and some can become dangerous if loaded too light.

[KN]

I would say that Nobade hit it on the head. I use 748 in my full 308 loads and my cases come out pretty clean.  KN

[jpuke]

Thanks for the info.  These were experimental loads that I'm not going to experiment with again - besides, 10 grs of Unique is cheaper.

[securitysix]

I'd be willing to wager that a good deal of the smoke you were seeing was from the bullet lube, rather than from the powder you were using.  I've used 748 out of a 14" braked T/C Contender and didn't notice a great deal of smoke - plenty of fire, though  .

[hubel458]

And ball powders should be 90% load density on up.In my cartridge
WW-760 gets a 500 gr over 2800fps with full load.WW-748 and
BLC-2 get 400 grain bullets over 3200 fps.There is picture of cartridge
in wildcat thread.Ed.

[John Traveler]

While I can't claim to be a propellant expert, I do have an ordnance and  chemistry background.

Ball powders were developed by Winchester-Western chemists early in WWII for the express purpose of expediting smokeless propellant manufactur of small arms and medium cannon. The war manufacturing effort made this a high priority.

The singular advantage they possess is that they can be produced from start to final packaging in a few days versus the month or so for granular single-based nitrocelluose powders.  This is accomplished by bringing the nitrocelluose out of solution batches as spherical colloids to form the "beads" or balls in their final form.  This is much faster than the time-consuming processes of extruding, perforation, several rinsing and drying stages required for granular propellants.

Solvent rinsing and drying is greatly accelerated, something that can't be rushed in the conventional cylindrical grains or the European flakes.  Graphite is added for antistatic properties.

The speheres are rolled and flattened somewhat to control burning rate.  Deterrent coatings and the size and mix of the granules or balls determines burning rate.  For cylindrical rods, the pierced hole also contributes to controlling burning rate.  Propellant for large calibre cannon can have several pieced holes.

There you have it:  Ball powders are faster (and cheaper) to make, and the end benefits include ease of flow through powder measures, and excellent perfomance for their intended pressure range.

[John Traveler]

As far as I know and remember from my ordnance training, the "celluose" in nitrocelluose comes exclusively from the "linters" or short, otherwise useless fibers that are left over from cotton processing.  Before the invention of smokeless powder, it was a useless by-product of cotten mills.  Lint can come from most anywhere in the textile industries, and is salvaged for that purpose.

WAIT A MINUTE!!!  I sorta recall that European smokeless powder manufacture gravitated to nitrocelluose fibers from TREES rather than the cotton linters as is standard for US powder manufacture!

Yes, I guess that would make sense.  From a chemistry point of view, cellulose is celluose, and plant fibers, from whatever source, is celluose.  It takes more steps and resources, I think to make it from tree wood, but it can be done.

I'll get back to you as soon as I find where I stashed my old textbooks.

[jhm]

Ed Hubel:  Are there any deer left in the Brighton area?  Years ago I used to do a little deer Hunting around the Chelsea area when I lived in Mi. I left 22 yrs ago dont miss the cold winters.   JIM

[hubel458]

I live at a little four corners called Brinton about 80 miles north of
Lansing, NW of Mt Pleasant 20 miles.We have lots of deer; there is
some in the back field right now.Have lot of turkeys.The area down
Brighton is getting a lot of crowding, like being a suburb of Detroit.ed.

[jerrl]

Years have dimmed my memories but seems to me the plant down in Glenn  County Georgia that bought all the fat lighter, made varnish out of it.  In any event, ain't no place on earth smells like Brunswick Georgia.