Rifle Fillers

[zephyr]

Here is a pressure study done by Michael McCourry and Sam Rose using various accepted fillers in a 470 load I believe the foam used was backer rod purchased at a local hardware store

470 Nitro Fillers

470 Nitro Fillers

www.b-mriflesandcartridges.com

 

[fourfive8]

Use of fillers is quite a controversial subject among reloaders. The theory behind it is to safely reduce case capacity for using smokeless in older, large capacity black powder type cartridges. The difference in burn characteristics and the difference in potential chemical energy between smokeless powder and black powder make interchanging the two ballistically tricky.

I use filler in some older guns and larger capacity cases if the guns are suitable for the higher peak pressures of smokeless. Dacron is a common low density filler. Some loaders use foam backer rod (as available from hardware stores) of approx diameter to match inside diameter of case. Both are used compressed enough to fill excess capacity with light compression of powder with bullet seated. I prefer Dacron to other materials available. Cotton fiber, kapok fiber and carded wool have also been used. IIRC, historically, carded wool was used in some 577-450 cartridges.

IMO, don’t do it if you don’t fully understand the difference between smokeless and black powder and theory of internal ballistics of cartridges.

 

[V.Veritas]

My understanding was that the filler is used to increase the powder load density (keep it bulked together and close to the primer) in order to prevent detonation and provide consistent ignition pattern of the load. (Repeatable pressure curve?!?).

The powder used needs to be appropriate for the application regardless if it is black powder or smokeless powder.
I need to look more into this. Thanks.

 

[JimP]

It's just that you get better ignition and burn of the powder if it is close to the primer.

So a piece of filler to hold the powder at the bottom of the case helps.

 

[yamoon]

Floral foam from your local florist.

 

[DWB]

I just use a piece of pool noodle that I cut with a case of which I sharpened the edges.

And then cut to length.

 

[Backyardsniper]

That's super interesting. There's so much to learn!

H4831SC. That's the powder I run in my K gun. I can switch between Hornady DGX, Swift A frames, and cutting edge solids without changing the powder charge and get basically the same POI

 

[Backyardsniper]

I purchased an industrial size roll of 3/8" foam backer rod for the times I do.need a filler. It is the perfect diameter for 470, 500, 45/70, 20 gauge shot cup spacer for hand loading TSS or magnum lead loads. I just snip off the length I need with a pair of scissors.

 

[PHOENIX PHIL]

This may not be correct. But another reason I've been told/read for having a full or at least nearly full case is that when not filled enough the case can explode when fired. This would another reason for using a wad with loads using faster burning powder but leaving an appreciable amount of empty space.

 

[Rare Breed]

My understanding was that the filler is used to increase the powder load density (keep it bulked together and close to the primer) in order to prevent detonation and provide consistent ignition pattern of the load. (Repeatable pressure curve?!?).

The powder used needs to be appropriate for the application regardless if it is black powder or smokeless powder.
I need to look more into this. Thanks.

correct. It stops double ignition. zit has been shown Dacron creates higher pressures which is why I use open foam. 8 DRs worth of experience

 

[fourfive8]

Understanding and knowledge are critical for safe reloading. Smokeless powder depends on progression of pressure for efficient and predictable burn. What many call detonations or SEEs can be caused by several things, some of them not well understood.

One is obvious… simple overload and too much pressure. These do happen and then the blame game starts.

Another is wrong powder in wrong application. One example would be slow, double base ball powder in revolver in cold conditions. A common combination for those infected with “magnumitis” in cold climates. Primer impulse pushes bullet Into forcing cone before powder ignites. Bullet stops. High percentage of powder, in flux cloud, ignites and bullet acts as bore obstruction. Kaboom.

Another involves improper use of wads or fillers. Filler or wad is added to cartridge after normal, recommended charge shows low and/or variable pressures and velocities. Filler/wad is added with intent of increasing consistency, foam or fiber- whichever. Sure enough it does increase consistency of burn but is too much of good thing without reducing load to compensate… then pressure exceeds safe level.

Or alternately in reality with adding a filler of some variety it is in fact adding a secondary projectile inside the cartridge case. The powder ignites and drives the filler or wad up against the bullet’s base. The bullet then becomes a bore obstruction. Three things can happen. 1)- the desired effect. Nothing much out of ordinary and ballistics are as expected, consistency is better and in normal range albeit at a slightly higher pressure. 2) A ring of extreme pressure is created at bullet’s base and the gun’s chamber is “ringed” in that area. 3) A kinetic event occurs at bullet’s base and likewise results in a “ringed” chamber.

No matter… proceed with knowledge and understanding ……. or not

 

[analog_peninsula]

I purchased an industrial size roll of 3/8" foam backer rod for the times I do.need a filler. It is the perfect diameter for 470, 500, 45/70, 20 gauge shot cup spacer for hand loading TSS or magnum lead loads. I just snip off the length I need with a pair of scissors.

I was going to buy 1/2”, but you say 3/8” is a better fit? This would be for a 500/416 and a 450 BPE.

 

[Backyardsniper]

I was going to buy 1/2”, but you say 3/8” is a better fit? This would be for a 500/416 and a 450 BPE.

Yeah I like the 3/8, I doubt it would matter a whole lot but, the 3/8 seems to be about a perfect fit in the 470. I used 1/2 in a 500 Jeffrey once and it worked really well in that. The 3/8 should be a lot easier to get into the .458 and .416.

 

[Backyardsniper]

I get off work in about 3 hours and I will double check when I get home, but I'm 99% sure its 3/8

 

[Backyardsniper]

I got a small bag from Lowe's and tried it out to make sure it worked and then went on Amazon and got a lifetime supply for $40

https://a.co/d/iLqFYu5

 

[Tintin]

Graeme Wright has tested load data using fillers for some cartridges in Shooting the British Double Rifle

 

[V.Veritas]

Maybe this thread should be moved to “Reloading” section.

 

[yamoon]

A ring of extreme pressure is created at bullet’s base and the gun’s chamber is “ringed” in that area.

An extensive study of chamber ringing was done by Charlie Dell in old single shot target rifles. His conclusion was that fillers contributed to the problem. I have a number of antique German target rifles, I do not use fillers even with small charges of IMR4227. Don’t want to take the chance.
Mike

 

[cajunchefray]

Graeme Wright has tested load data using fillers for some cartridges in Shooting the British Double Rifle

Mr. Wright has some extensive testing with fillers as well as @michael458.
Read every page of this testing.
Very informative..
My limited experience is with 450/400 Nitro, 3 inch and .500 Jeffery.

For the.400 Jeffery, I used 1/2 inch foam backer rod, cut to length so that the powder Relader 15, in this case, a lighter charge than H4831, for less recoil. In other words, .50 diameter foam rod, twisted down to. 40 to fit in the neck of the.450/400 case, just long enough ((.90 inches for my load), to just slightly compress the powder.
Accuracy was more consistent.

In the same method, I used 5/8 inch foam backer rod for a minimal charge of Varget in the .500 Jeffery, to get.500 Nitro ballistics.
In other words, I didn’t want 2400 fps from the.500 Jeffery, just 2150.

Carefully read Mr Wrights data, and pressure tested, as well as @michaal458 post.
Of course, aSafe hand loading procedures for your rifle.

Proper application of fillers work very well.
No residue, consistent velocity.

 

[analog_peninsula]

I got a small bag from Lowe's and tried it out to make sure it worked and then went on Amazon and got a lifetime supply for $40

https://a.co/d/iLqFYu5

Perfect. Thank you.