Kaowool as a case filler

[303Guy]

Has anyone heard of or tried Kaowool as a case filler? It's a ceramic fibre so is completely inert, cannot absorb moisture and can take one hellava temperature (not of any relevance but it's what Kaowool is used for - heat insulation). Dacron has some of those properties but is more springy which is a desirable property. I have some and when I saw it today the idea of using it as a case filler struck me. It may have better bore cleaning properties than some other fillers. Dacron has zero cleaning properties but is an ideal powder positioner. Kaowool is a bit heavier than Dacron - a 303 case full would be 6 grs and it can be compressed - a lot! I would imagine it would make a good boolit wad.

[DrCaveman]

Have not heard of that before, but I have a bunch at my disposal and am on a kick for trying fillers.

Dacron with imr4227 has helped a bunch. With rx7 medium loads too. I haven't done the wheat germ/ cream of wheat path yet but might soon.

I like that kaowool is of much smaller fiber size than say fiberglass. Does seem like it would provide a polish to the bore. Gotta be something like 3000 grit, but I'm just pulling that out of ****.

Hmmmm

[quack1]

You say it is a ceramic fiber, some ceramics can approach the hardness of diamond. I'd never take the chance of running something that could be extremly abrasive and/or harder than steel down any of my barrels

[captaint]

I was gonna say - If it is that resistant to high temps, it might not be a good thing. That "ceramic" business, also doesn't sound like a great thing, either. I guess, for me, it would be one of those - has anybody else ever used this stuff, and how did it work out ??? Mike

[Doc Highwall]

I was thinking about starting a fire with 0000 steel wool in the fact that it can be lit with a match and burns, but also how fast it absorbs heat and how this might relate to the ceramic fibers and melting. The hardness factor mention also would make me inclined not to use it.

[303Guy]

Mmm.... but it might be a good bore cleaning and polishing material - for limited use only in rough or 'dark' bores. But I think the worst aspect is all those tiny fibres blowing out the muzzle but nothing has been said about it as a health concern for normal handling of the stuff.

Cotton wool can be ignited in a barrel but usually it comes out unscorched. Steel wool might get mingled with a few powder granules and possibly could ignite but one would expect it to require more time exposure to a flame.

[Jim]

Since case filler is the topic of discussion, I'd like to throw Kapok on the table for consideration. 30+ years ago, my mentor taught me about it and I'm still using it.

I wrote an article about it and Willjen was kind enough to publish it in castpics.

[303Guy]

Thanks, Jim. That was an interesting read. You mention polyester and Dacron - something I'd like to point out is they're not exactly the same. Dacron is polyester but not necessarily the other way round. Dacron is a fine polyester fiber and that's important. The course stuff is simply too course for my liking. I've found that a fair amount of Dacron seems to act as a wad behind the boolit. Kapok I should imagine will be the same. So would cotton wool but cotton wool can ignite grass fires!

Well, I'm still looking at this tuft of kaowool and wondering about it. When rubbed on a boolit it does remove the shine leaving a sheen and when rubbed vigorously on a dull boolit is removers the dull grey. I don't see it as being particularly abrasive. Plain paper will do that.

[Geppetto]

I was thinking about starting a fire with 0000 steel wool in the fact that it can be lit with a match and burns, but also how fast it absorbs heat and how this might relate to the ceramic fibers and melting. The hardness factor mention also would make me inclined not to use it.

I can say from first hand experience that I doubt Kaowool would burn or melt during a trip down a barrel. I use it in my blacksmith gas forge which is probably +2000 degrees, and the fibers are pretty much intact. I would be more concerned about the dust that would probably result, your really not supposed to handle the stuff without a respirator. Ceramic fibers can turn into a small hard particulate and when they get in your lungs its kinda like silicosis (from small hard silica particles) or Mesothelioma (from small hard asbestos particles). For those reasons I'd hold off on shooting it out of a gun, which I think would really result in a lot of dust and airborne particulate.

[303Guy]

Point taken - thanks, Geppetto . There is probably no need for it anyway. Besides, I like wheat germ and also Dacron and for special purposes there is corn meal. Wheat bran has its place too. Kapok is a bit hard to find. I had some but have lost it (old life jacket).

[41 mag fan]

That ceramic wool is an insulator they sell at a fireplace store down the road. We used it as an insulator on our wood burning furnace...they use it in power plants too or used to.....it wont burn thats for sure.

[stocker]

I can't say I've ever heard the name before. I do wonder if it's the same stuff you sit on the burners of natural gas fireplaces to simulate hot embers. Ours hasn't burned away in 5 years and I had to get 1 pound bag to obtain it.

[303Guy]

This is what it looks like

[Frank46]

Worked in a tank farm way back when. You thought the fibers from asbestos are bad. Since it is a spun ceramic fiber it won't break down in the body. And you get the same itchy scratchy feeling just like the fiberglass insulation. Used it to insulate steam and oil lines. Frank

[Firebricker]

Using kaowool and not getting paid to touch that nasty stuff ooh the horror LOL It's pretty nasty stuff I doubt it would be worth the hassle plus I wouldn't want it going through my barrel. If it did by chance wind up working well the "bulk wool" version would be easier to get small consistent amount since it not in blanket form. FB

[longbow]

Let's start with Kaowool replaced asbestos in many applications because it is not a health hazard as asbestos.

Then the next bit is that since it is a ceramic fiber I suspect that is is fairly hard (my opinion only without checking facts) and so may be abrasice to barrels.

Just to bring this absorbing moisture issue into perspective, I loaded up a few .303 rounds using COW filler and kept a bunch in my basement and took 5 outside in an unsealed but somewhat protective baggie. I left the respective batches for about 1 year ~ yes, 5 rounds outside in an open baggie for 1 year exposed to snow, rain humidity changes, etc. Then I took all out to the range and shot them. I could not tell the difference between those stored in the basement and those stored outside... or for that matter some recently loaded in the same fashion with same components.

An over bore cartridge with steep angle shoulder may provide different results but I have not fear of packing or pressure spikes or whatever using cereal filler after that.

I develop my loads with filler working up with powder and down with filler just as one would develop any load.

It works for me!

Longbow

[303Guy]

I was using wheat bran with shotgun powder. Some older loads (a few months old) left much of the wheat germ in the case. No change in pressure though. It could have been bugs weaving silk in the stuff! I switched to wheat germ because it is oily and flows well plus it is light and even sized and easier to pour into the case. Corn meal is easy to handle but raises chamber pressure considerably which is great for slow powders in reduced loads. We don't have COW here so I cannot evaluate it. I've ruled out kaowool for testing!

Moisture should not really be an issue in a sealed cartridge and even if the cartridge can breath, surely COW does not get damp and clump in the cupboard? Corn meal does not, nor do the other two I use. Cotton is a natural fiber and that does not absorb moisture and go soggy. What could solvents and other vapours in the powder itself do to fillers? Different powders may have different effects. Or not.

[longbow]

There are arguments that cereal fillers can absorb moisture and "cake' which I cannot deny. however, my testing indicates that any absorption of moisture must be small and does not seem to cause any problems.

Personally, I think that the pressures developed in even low pressure cast boolit loads exceeds the pressure required to extrude the cereal filler so is basically irrelevant. Personal opinion only.

I have to compare granular fillers to Puff-Lon which is a commercial filler where the supplier recommends reducing SAAMI recommended loads by 10% when working up loads with Puff-lon

I have been told and read that fillers of any kind are "evil" and will ring chambers. However, personal experience to date indicates that fillers provide 100 % loading density preventing double charges of powders that fill less than 50% of the cartridge volume.

My suspicion is that many incidents of destroyed guns using reduced loads without fillers where "I couldn't have double charged..." are in fact double charges not SEE. Again, personal opinion only.

Longbow

[303Guy]

I agree. Fillers provide 100% load density and allow the use of slower powders.

"I couldn't have double charged..." are in fact double charges not SEE.

My sentiments too. Loading for 40 years without incident tells me something. I'm still young (but old enough to have been loading for 40 years) and I find things I did yesterday that I have absolutely no recollection of! Like finding a boolit in the test tube that I have no recollection of firing! So double charging is an easy thing to accomplish without knowing it. Using a filler with a slower powder solves that possibility. Fillers have another benefit - they provide a positive stop for the boolit to rest on should they bumped.

The 'evil' fillers that will ring chambers can be put to rest. I've mentioned before about my pig gun cases getting stuck because of a small charge of very fast powder forcing the neck to expand into a rust pit in the chamber neck with no sign of pressure on the primer or elsewhere on the case. That's with filler but here's the rub, sometimes the filler doesn't get blown out the case. It gets channels in it so it couldn't have been involved in the neck pressure. Nor were the boolits getting riveted. I captured some and they were intact. These were subsonic loads.

Some have mention COW caking in the case, discovered by dismantling the rounds. COW is made of starch which will behave differently to wheat bran and wheat germ and corn meal takes a helluva lot of water and heat to soften and cake. Even so, I won't rule out the possibility but I somehow doubt it will in a cartridge.

[longbow]

303guy:

While I do not consider myself an expert on fillers by any means, I have used both cornmeal and COW quite a bit and am very happy with results so far. I have not had the channeling you mention but that may be due to specific load and circumstances which I have not produced.

As for "caking", I mentioned that I left 5 loaded rounds outside for a year and a bunch of others in the basement for a year then pulled boolits from each batch. I couldn't tell the difference in the COW from either batch. In both cases it was packed but "friable" ~ it was easily poked out and crumbly. I also shot both batches and could not tell any difference in performance.

I also have some old information I would have to look up now to get the source but it commented on using 1 teaspoon of graphite powder in 1 cup of cornmeal or COW for filler use.

Just recently I made a mistake when loading and double charge with COW! After adding filler I always check to make sure it is about 1/2 way up the neck and so it was but I had used two charges of COW and no powder. When I pulled the trigger on that cartridge, the boolit left the barrel... just but the COW plug was just behind the muzzle. Now, again, I have been told that COW will form a hard plug like wood from just primer pressure but this unintended test gave somewhat different results. yes, the COW was fairly well packed after ramming a boolit out of the barrel but it was still quite friable and crumbled when pushed out of the barrel. Not hard like wood at all.

So, while cereal filler may not be suitable for every cartridge or every loading situation, I have had good results and intend to keep using fillers... just not Kaowool!

Longbow