what is the purpose of using filler in reloading and what is used? i may be missing something in my reloading for my double rifle. it is a .43 mauser i have been loading 32 gr. of 4198 pushing a 375 gr rn lead bullet @ 1350 fps would a filler improve the performance?

When loading a large capacity case with a small amount of powder, filler is put over the powder to hold the powder over the primer for proper ignition. I have seen fillers for sale, some just use oatmeal or corn meal. When filler is not used in this situation, there is a potential for a hang fire and a dangerous over pressure condition. What can happen is the primer flame will burn over the powder laying on the bottom of the horizontal case and push the bullet out into the barrel, prior to the powder burning, when and if the powder does burn, the barrel is plugged with the bullet and the rifle could blow-up. Filler is used to give uniform, consistent and proper ignition limiting the possibility of a hang-fire.

thanks that is good to know. do you put anything between the powder and the filler? regards bob

I don't put anything between powder and filler. When I shoot CAS, I use Clays powder and Quaker white hominy grits with my 200gr RNFP 45LC pill. The combination works well. I don't have to clean the brass, it is cool to the touch, and the recoil is practically nill (nice for competition).

Hey usps, Back in the `50s & `60s, the NRA used to wrtie a good many articles about Fillers. The "HUGE" problem was/is that occasionally they will "Ring" a Chamber or a Barrel.

That means the Pressure exceeded the Plastic Limit of the Steel and caused it to expand beyond it's ability to retract, but just not quite enough to Ka-Boom.

Due to that, I've never used Fillers and went with Bulkier Powders to (nearly) fill the Cases when I was shooting a lot of Lead in Rifles.

I do not know anything about a .43Mauser, but if it is a Bottle Neck style Case, they tended to cause more "Rings" with Fillers than a straight Case like a 45-70.

If you understand the Secondary Explosion Effect, that seems to fit the situation real well.

Best of luck to you.

As stated, fillers are used so a small amount of powder doesn't rattle around in a cavernous case. It's usually what's called pillow ticking or pillow filling.

Buy some here:Kapok fill
Kapok is a natural fiber. The stuffing in my pic is some kind of polyester I bought ages ago.

thanx for the tiking suggestion and the rest of the info. on this thread. it is informative and helpful.

Hot core should stick to his CHE BS......
It is the use of wads that "ringing" is attributed to. There is a distinct difference between a wad and a filler. Apparently Hot Core is confused as usual.

Most instances of "ringing" are with the use of wads in straight walled cases like the 45-70 not in bottle necked cartridges.

SEE (Secondary Explosive Effect) has absolutely nothing to do with fillers.

Fillers are used by a great many cast bullet shooters with medium and slower burning powders to enhance consistent ignition and improve accuracy. The best fillrs are Dacron, Kapok and the shotgun buffers. Fillers serve a very useful purpose with cast bullets if used properly.

If you stop and think about it the "wads" in shotgun sells are actualy fillers. How many of them are shot every year without any instance of "ringing"?

Larry Gibson

Here is some of what I have learned about using filler:
Dacron fillers are very appropriate to use but only with the slowest of the "pistol" type powders (4759. 5744, 4227, 4198, etc.) and the medium and slow burning powders when case loading density is less than 80-85%. Dacron filler used within that parameter gives excellent results. If it is used outside of that parameter, Dacron filler generally does not work well. Do not use filler in loads using Bullseye, Red Dot (any of the Dots for that matter), or Unique, as they are fast enough without. Depending on the load and how much case capacity is involved for 2400, 4759, 57344, 4198, Varget and Reloader-7, filler is likely appropriate. For the latter group, it fills up the space between powder and bullet base. This does three things, it gives you an additional check against double charges (maybe), fills up dead space between the powder and the bullet base, and if the base of the bullet protrudes into the space below the neck, it seems to improve accuracy.

Dacron is fluffy and expands to fill the case after being pushed in through the neck. The size of the tuft required depends on the volume of airspace to be filled. Use just enough to fill all of the “free” space between the powder and the bullet base and do not overly compress the Dacron. You can reach the point where there is "too much" and then ignition and pressure ES and SDs will increase. Just enough to fill the air space with slight compression from seating the bullet is the right amount. Remember the Dacron filler will increase ignition efficiency and also pressure along with velocity. Even when working with filler as light as Dacron, the weight of any filler must be added to the bullet weight when working up a load. If you work up a maximum load for accuracy without filler and then add filler and test that load, it is likely that accuracy will suffer. When the Dacron filler is used ignition is more efficient, there is increased pressure and thus increased velocity. If the load combination being tested is close to being at its maximum efficiency the higher velocity can cause the bullet to exceed that maximum and inaccuracy is a result of that, not the use of the filler. If the load is reduced and worked back up to the same velocity as the load without the filler then accuracy will likely be enhanced and it will be achieved using less powder.

With some of the faster powders general accuracy may be the same without the Dacron filler, which is fine if most shots are fired with the firearm held in a relatively level position. However, in larger cases when shooting at angles, up or down, the position of the powder in the case is not consistent and that can cause an increase/decrease in velocity or a very large ES to occur, causing severe zeroing problems. In this scenario, therefore, Dacron filler would be employed only for the purpose of decreasing "powder position sensitivity". The use of the Dacron filler keeps the powder positioned in the rear of the case, in consistent proximity to the primer/flash hole and negates the adverse affect of "powder position sensitivity".


The possibility of “ringing” either a chamber or barrel is a very real and legitimate concern, usually (at least in theory) associated with the improper use of fillers or wad columns. There is also a school of thought that maintains that ringing can happen when using large cases without filler with small charges of fast powders that result in a lot of empty air space in the case. This theory is based on the premise that at ignition the expanding gases compress the air in the case until the gases smack the back of the bullet and are forced outward 90 degrees to the bore, this creates an area of higher pressure just behind the bullet. Allegedly, it is that area of higher pressure that causes the ring. So the theory is that the air space between bullet and powder must be eliminated. Some people use cream of wheat or shot buffer. If you choose to go this route, after charging, fill the case with buffer material to the top and then seat the bullet, this should only be done in a way that lightly compresses the buffer material against the powder thereby holding the powder against the primer, you must slightly compress the buffer material so that there is no mixing of powder and buffer material resulting in poor ignition or no ignition at all. By doing this you get two benefits. 1) More reliable ignition and 2) an excellent gas check (read freecheck). There should be no gas cutting because the gases will not reach the bullet thereby reducing or even eliminating leading. Some people use Kapok or Dacron and use just enough to lightly hold the powder charge against the primer. Never compress the filler on the powder so as to leave an air space between the base of the bullet and the powder charge. If there is a space, the filler becomes a “second (but primary) projectile” within the case and the potential for “ringing” of the chamber/barrel is increased when the filler-wad slams into the base of the bullet.

Hope this is of some help. Have a great day.

quote:

What can happen is the primer flame will burn over the powder laying on the bottom of the horizontal case and push the bullet out into the barrel, prior to the powder burning, when and if the powder does burn, the barrel is plugged with the bullet and the rifle could blow-up.

A slight addition ; Under certain circumstances when using a reduced load of a fast powder in a rifle

cartridge ,powder with out a material of compaction ( filler ) can lay away from the primer ; thus creating

an explosive condition known as over or after-burn . Powder's are meant to be kept against the primer

for a VERY GOOD REASON !. This can not only cause bullet barrel lodging ,it can also BLOW UP YOUR CHAMBER,

BOLT or BARREL !. When working for Hercules Powder I was witness to this phenom during a demonstration ,

It isn't pretty !. Remember powder is meant to burn inside out ward , not outward in , such as a lay over

affect creates with in a closed combustion situation ! .

I use filler when loading for my British Double rifle elephant guns.

I use either Dacron Polyester, or a foam plug I cut with a chamfered [sharpened] 50 BMG case.

I have never had any roblems with filler...

BUT, WHEN I USE FILLER IT IS ALWAYS COMPRESSED, between the powder and the bullet.

Some of my loads use as much as TWENTYFIVE grains of Dacron. Weighed for each round loaded.

quote:

or a foam plug I cut with a chamfered [sharpened] 50 BMG case.

Bless you!

What is the best cutter for foam for the 416 Rigby using RL-15? A cut down and chamfered Rigby case.

Thank you again,

LD