I was reading a thread on Saubier and one guy was talking about some loads (pistol powder) for his 17AH and how he used poly fill in cases that had a small powder charge and the difference in velocities due to the powder being held together at the bottom of the case. This is new to me, but the velocity difference he was getting was pretty significant so I thought I would look for some more info here. BTW, what is poly fill?
Poly fill in cases?
- Thread starter KDX
- Start date
Well, either he means this http://2.bp.########.com/_cjBiZ2nogXY/Sp6YPMaRKtI/AAAAAAAAA0M/-LoftGZMmNo/s400/poly-fil.jpg
or he's putting spackle in his cases lol, that would be something else.... you'll have to ask him to clarify, either way.......
or he's putting spackle in his cases lol, that would be something else.... you'll have to ask him to clarify, either way.......
That's the idea
When they talk about pillow stuffing just remember they mean the synthetic fluffy stuff. Don't go shoving goose feathers into your ammunition
As to where it goes, light some of that stuff on fire, tell me how much you have left after it burns, now imagine the same thing at 20-30,000 psi, approx 1400 degrees.
That's the idea
When they talk about pillow stuffing just remember they mean the synthetic fluffy stuff. Don't go shoving goose feathers into your ammunition
As to where it goes, light some of that stuff on fire, tell me how much you have left after it burns, now imagine the same thing at 20-30,000 psi, approx 1400 degrees.
Residue is residue and personally I wouldn't want it anywhere near my firearm, collecting in the grooves or chamber, no thanks. Just my opinion of course, I could be way out to lunch
Alright, let me chime in on this one because I've got a few notches in my belt when it comes to using this kind of thing for fireforming with uber-light loads of pistol powder in larger cases like 308.
The poly-fil (or cotton, or whatever you use - poly-fil is preferred because it doesn't like to compact into a hard-ass wad like cotton does) goes on TOP of your reduced powder load but BEHIND your bullet (or whatever you're sticking in the case neck, like a wax plug etc.)
So, from the bottom up, the 'train' looks like this - primer, powder, poly-fil, bullet/plug.
What poly-fil does in fireforming, for me, is separate my cream of wheat (yes, the dry porridge) from my powder - such that, if I shake my cases inadvertently prior to firing, I don't get a powder-CoW mix.
In reduced loadings, like the one being described, you can still have a more consistent powder density by using the poly-fil to take up the excess case volume which is now NOT filled with powder as it is in many normal loads. This ensures more reliable ignition, since the powder charge is still 'packed' by the inert filler. Many people think this leads to more consistent velocities, and I've seen data to that effect from some more serious handloading blogger-types.
I've never seen any poly-fil residue from my fireforming loads, but that doesn't mean it won't cause residue issues in higher-pressure bullet loads. YMMV, as with anything. Frankly, I usually see unburnt poly-fil flying downrange like a shotgun wad - anyone else with similar experience? Or do others find that it becomes a sticky mass/disappears?
-M
The poly-fil (or cotton, or whatever you use - poly-fil is preferred because it doesn't like to compact into a hard-ass wad like cotton does) goes on TOP of your reduced powder load but BEHIND your bullet (or whatever you're sticking in the case neck, like a wax plug etc.)
So, from the bottom up, the 'train' looks like this - primer, powder, poly-fil, bullet/plug.
What poly-fil does in fireforming, for me, is separate my cream of wheat (yes, the dry porridge) from my powder - such that, if I shake my cases inadvertently prior to firing, I don't get a powder-CoW mix.
In reduced loadings, like the one being described, you can still have a more consistent powder density by using the poly-fil to take up the excess case volume which is now NOT filled with powder as it is in many normal loads. This ensures more reliable ignition, since the powder charge is still 'packed' by the inert filler. Many people think this leads to more consistent velocities, and I've seen data to that effect from some more serious handloading blogger-types.
I've never seen any poly-fil residue from my fireforming loads, but that doesn't mean it won't cause residue issues in higher-pressure bullet loads. YMMV, as with anything. Frankly, I usually see unburnt poly-fil flying downrange like a shotgun wad - anyone else with similar experience? Or do others find that it becomes a sticky mass/disappears?
-M
Looking at my first reloading manual (Speer #9!), it discusses this and recommends either kapok or Dacron, with the latter preferred. Both are listed as pillow fills.
After the case has been charged with powder, seat a 1/2 to 1.0 grain tuft of filler lightly on the powder charge with a small diameter dowel. This filler will spring somewhat to fill much of the available space and hold the powder to the rear of the case. Trial will show the proper amount of filler to use. If visible shreds of filler exit the bore on firing, reduce the amount of filler slightly. The proper amount of filler will be entirely consumed on firing and will produce no undesirable bore fouling.
Never tried it myself and have no idea if newer Speer manuals still mention it (using Sierra now), but this sheds some light on the residue issue.
tactical870
CGN Ultra frequent flyer
- Location
- Buckhorn, Ontario
In my bp cartridge loads I use cornmeal as filler. I'd imagine it would would just fine for smokeless too....
vagrantviking
CGN Ultra frequent flyer
- Location
- High River, Alberta
Probably be OK in a straight case. Just add it to the weight of the bullet for calculations and treat as a compressed load.
When I think of a wad of cornmeal or cream of wheat below the shoulder in a bottleneck case and try to envision 60 000lbs of smokeless pressure trying to force it through the neck it leaves a very bad feeling.
Johnn Peterson
CGN Ultra frequent flyer
- Location
- Chemainus B.C.
In some instances, using fillers has made a difference for consistency and accuracy. As example, in the 45-70, for light loads using some of the faster burning powders I started out using some shredded cotten balls to take up space and keep powder closer to the primer. A product I found to work even better yet is one called Stopdrafts foam backer rod, made by Tago. It is 1/2" diameter and I cut it to fit the available space between powder and bullet. It doesn't seem to leave behind any residue and all you notice viewing from the side is what appears to be a puff of dust when the shot goes off. As of late for those lighter loads, I'm now using/trying Trail Boss in most applications.
Probably be OK in a straight case. Just add it to the weight of the bullet for calculations and treat as a compressed load.
When I think of a wad of cornmeal or cream of wheat below the shoulder in a bottleneck case and try to envision 60 000lbs of smokeless pressure trying to force it through the neck it leaves a very bad feeling.
When using cornmeal or cream of wheat for fireforming, you're not using a 60,000 psi load - definitely far from it in my case. Further, to protect against moisture-based hardening into a "slug", it's important to load up as close to range time as possible - not days in advance. Also, some (including me) will press the case neck into a thin sheet of soft wax if there's going to be more than a few hours' delay - forming a plug impervious to moisture.
YMMV, but cream of wheat for light-load fireforming (I'm talking 4 to 8 grains of Bullseye or Unique in a 308 case, absolute maximum) is a pretty widely used practice.
-M
vagrantviking
CGN Ultra frequent flyer
- Location
- High River, Alberta
Using cream of wheat and other fillers in fireforming is certainly common and safe when done right. Done it myself a few times, usually with just a plug rather than a bullet.
I was worried that some people might be getting the impression that they should top up all their rifle loads with the stuff.
I was worried that some people might be getting the impression that they should top up all their rifle loads with the stuff.
