Probably could ask this on the reloading board, but it is a big-bore question. Those of you loading the BP and nitro expresses at nitro-for-black velocities: What do use and what do you avoid as fillers? I am thinking specifically of dacron over, say, 4198 in a .450 NE case as suggested by Ross Seyfried, but I would think the principles of safe filler use would apply to most of the big nitro cases.

There has been a lot of back-and-forth on this. Several people have reported ringed chambers, etc. I have used Dacron batting as filler for a few hundred reduced loads in my 416 Rem.

I did find that I got pressure signs on the brass if I did not use a tightly packed column of filler.

Once I started using a lot of tightly packed filler I got good accuracy and very repeatable velocity.

I think a loose wad of filler can melt, slam forward and act like a bore restriction at the base of the bullet when it all comes together at the throat. The bigger, tightly packed wads just melted at the back and came out clean.

None of them fouled the bore except cotton. (Which is highly recommended by some.) Cotton left stray fibers in the bore.

Don

I used kapox in the .38-55 with 4759 for schutzen shooting. It was very accurate, clean and consistant. But the loads were light and cast bullets were used.

I just used a small piece of it and pushed it to the bottom on top of powder. That small piece was weighed once in a while to maintain a approximate amount.

I have done some reduced loads in the 375 and the 30-06. One of the best fillers is the powdered senthetic stuff made for shot buffers for shot shell. I got mine from Precision Reloading if I don't misremember. Good hunting. "D"

Bill __

Fillers are perfectly safe as long as the filler fills the empty air-space fully, putting the gunpowder under some compression. My preference is rigid foam, like styrofoam, for straight-wall cases, and the "spongey" variety of foam (padding) for bottleneck cartridge cases. I also add a thin disk of cardboard (tablet backing) between the gunpowder and the foam to preclude charring and/or melting of the filler.

Good shooting.

Robert

I ringed my 9.3x62 with reduced loads and dacron and .365 95gr pistol bullets. There was enough dacron to stop the powder moving and ring the chamber...... so my advice is don't risk it.

Gents, check out Accurate arms powder XMP5744, I've used it for years with great success. They claim fillers are not needed. Do some research, and call the co. for more info.

FWIW, I helped a buddy do some nitro for black loading of some old BP Express rifles some years ago. We used kapok from some old life vests. In the process of working with the loads, I looked inside the barrels after each shot to check for kapok left in the barrels, since I'd heard of this happening.
There were several occasions when there'd be a tuft of kapok left in the bore. I'm not sure how much of a problem this small tuft of kapok could create, never having used fillers myself, but I'm just afraid of it. Not all uses of reduced loads would conveniently allow one to check the bore after EVERY shot, and some reports of these small tufts of kapok left in the bore causing ringing of barrels.

I just don't want to find out "the hard way," and my buddy, on being shown these tufts left in the bore, eventually refused to use them any more in those fine old BPE rifles.

It just isn't worth it to me to risk a good rifle, and who'd buy a rifle that ISN'T a good one???? Much easier to just tip the barrel up or down before shooting, I think.
That's my take, anyway.

I load Varget with packing foam cut with a sharpened case and now with a regular hole punch. Its for a .500 Express - .400 grain bullet at 1950 over my chronograph. I haven't had problems yet.. I heard about the powder butch mentioned. I will try it next. Sounds interesting. Good luck!
Aaron