From: njohnson@nosc.mil (Norman F. Johnson)
Newsgroups: rec.guns
Subject: Re: [RELOADING] dacron fillers, gas checks, etc.
Date: 21 Apr 1994 21:54:55 -0400

Jeff,

# The use of Dacron filler as a wad was mentioned as an alternative 
# to using gas checks.  Can someone please provide some more infor-
# mation about this.  How do you do it?  Is there a quick and dirty 
# way of cutting out little circular patches?

Wads (or various fillers) have been traditionally used with cast 
bullets because the powders/charges generally recommended for use 
with cast bullets are faster powders that, as a rule, take up 
only a small part of the volume of the case capacity.  The 47-70 
is an excellent example of this with it's very large case that 
was designed for black powder.  Fillers have been used to protect 
bullet bases also but their traditional use is as described.  

Some (most) powder's ignition characteristics are sensitive to 
powder position in the case, so wads and fillers have been used 
to hold the powder in close proximity to the primer.  This helps 
keep ignition more consistent and theoretically produces more 
accurate loads, if all other conditions are close to optimum. The 
position of the powder is not as critical to accuracy as is the 
consistency of it's position.  

With a tubular or flake powder, if it is positioned near the 
primer it will yield a higher velocity than if it is positioned 
at the far end of the case.  Powder leveled out in the case will 
provide a velocity somewhere between these two extremes.  Ball 
powders are said to act in the reverse of the above but I have 
not verified it because my approach to cast bullet loading is 
somewhat different, but that is another story.

         ---------------BUT, BEWARE !!!----------------

The use of wads and fillers to hold the powder back against the 
primer has resulted in the ringing of numerous chambers, 
especially those of straight walled cases such as the 45-70.  
Ringing is a radial enlargement of the chamber, usually occurring 
at the base of the bullet in a cylindrical portion of the 
chamber, i.e., in the body of the cylinder or in the neck of the  
cylinder but, as far as I know, not in the transition of the two.  
It can happen either suddenly (one shot) or gradually over a 
series of shots.  

This phenomena was first recognized (to my knowledge) in the 
early seventies by serious cast bullet shooters. The word has 
been long getting out but, although infrequent, the ringing has 
ruined many a chamber.  The NRA and the Cast Bullet Association 
(which made the NRA aware of the problem) has for quite some time 
recommended that no fillers or wads be used in any loads where
they are positioned against the powder so as to leave an air 
space between the wad/filler and the bullet base.

The reason for ringing has not been established, but some hold 
that the wad or filler is propelled forward and when it strikes 
the base of the bullet, the bullet acts as a secondary projectile 
and rings the chamber (in the same manner that a bulged barrel is 
likely to occur if a bullet is lodged in the barrel and another 
is fired behind it).  

Three methods are commonly used to avoid the above discussed 
problems of powder position sensitivity and chamber ringing.

1)  Select powders that fill the case enough to avoid the 
positioning problem so no filler is needed.  

2)  Position the powder by raising or lowering the rifle muzzle 
before each shot - again no filler required.  

3)  Select a powder that has shown to be less position sensitive.

Two powders that have been used to accomplish 3), are 700X and 
Unique.

Wads that stay up against the bullet base do not pose the ringing 
hazard described.  Polyethylene (HDPE and LDPE) wads are commonly 
used in place of gas checks to protect and seal bullet bases.  
Wax wads of all sorts are used to do the same.  

# by powder compression, or lack of.  I've heard that having the 
# case 100% full is optimal.  

Theoretically 100% case fill is best but it does not usually work 
quite that way.  Only trial and error will tell for a given 
gun/ammo combination.  I find that selecting a powder that will 
provide somewhere near 100% loading density is a reasonable way 
to start, but am not surprised when another load that is consid-
erably less case filling is better.  

# A few of my heavy loads for my .44 Magnum are slightly com-
# pressed.  Here's my dilemma.  For light target loads for 
# the .44, is it better to use the .44 Magnum brass and have it 
# roughly 50%-70% full of powder or should I trim it down to .44 
# Special length and have a larger volume of the case full of powder?

Here again, only trial and error will tell, theory notwithstanding.  

God Bless!

Norm