The use of fillers, tests and their results is always interesting to me. I've read all of Bell's and Seyfried's articles and distinctly recall that in a subsequent issue Bell specifically warned against the use of closed cell foam fillers. Unfortunately I don't recall if he mentioned a reason other than what he thought was too high a pressure....which seems enough not to use them.
The "stutter step" Bell mentions is curious but, as Mike observed, the pressure does not increase to the level it would ring a chamber.
As with Mike I've used fillers for....well, a long time, decades. Right after reading Wrights book on doubles I eschewed granular fillers such as COW and resorted exclusively to open cell foam fillers. If memory serves, they were 3rd on Bells list. His first choice was cotton balls, then Dacron then open cell foam. I've never tried backer rod but suspect open cell foam acts much the same. J.C. Munnel has used Styrofoam packing peanuts for quite a while and from his writings no problems have developed.
That fillers are controversial goes without saying. However, as with Mike I've never seen a chambered ringed because of their use. Also, as with Mike, that it happens cannot be denied. I have old, German rifles that have fired hundreds of rounds of cartridges loaded with an open cell foam filler over Unique, Reloder 7, IMR-4227, IMR-4198 and 4895 and H-4895 and have yet to ring a chamber. Maybe I've been lucky and might ring one today if I shoot one of those rifles and loads. However, given past experience it seems highly unlikely.
Last edited by sharps4590; 08/16/20 08:35 AM.
