DocHunter,

Just my humble opinions but I'll try to answer your questions as best I can.

The reasons for filler (also the advantages) are:

1. Gain more efficiency from a given charge (a higher average muzzle energy). This is accomplished by restricting blow-by around the projectile.

2. Achieve tighter velocity distribution. This is accomplished by more consistent use of breech gases. While not important at short range with fast projectiles, can be with slower projectiles at more distant range.

3. Inhibit bore erosion. By preventing some portion of the blow-by, less erosion of the bore occurs prolonging the quality and accuracy of the barrel. (just my theory)


The disadvantages of filler.

1. An extra step in loading. (I think thats it)


Here are some thoughts on different types of filler. Rather than listing disadvantages, I list the advantages only.


Ground Oatmeal:

1. Light weight adding less ejecta weight having the effect of reducing its contribution to recoil and limiting the effects, caused by the weight of filler, which lower the efficiency of the charge.

2. Soft so potentially less abrasive.

Cornmeal.

1. Denser giving more filler per unit volume.

2. Easy to meter from a flask.

I've not done any comparisons of the two and really don't know how the effects of each may differ in terms of performance.

Phil