I will concede that there may be circumstances where the use of fillers may be warranted. RIPP's big bore comes to mind though I have no experience with those so can't comment specifically. Hence my question about who else uses them above. Seems the big ones may not be conducive to properly regulating "non-fillered" loads with current powders?

However, fillers are very frequently an easy way to, seemingly, improve performance of rounds when a little more work in handloading would demonstrate that they are not needed. I used them for quite a few years before learning little by little that with proper loads they were not needed for my purposes {generally, reduced loads}, a finding that was asserted by many others who gave them up also. This not so much for the reason that they are "bad" but rather they are not needed. This is what I meant by a "crutch". Not a demeaning comment, but merely to address the fact that just because a practice renders improved performance sometimes it may not be the goto option most of the time, especially when there are lots of component company data options given these days. A crutch isn't needed to help me walk when I'm fit, but if I bust an ankle I don't want one crutch, I want two!

I really do not mean to be dogmatic on the issue. To each his own. If a fellow wants to use them, what can I do about? Maybe he needs to, maybe he doesn't. However, as far as recommending them on an open forum, I won't do it for a variety of reasons. I merely cannot recommend fillers because I have had so much success without them and have read of many others who do as well and while some of the hazards in their use are well-known, some, and more importantly, the remedies to them are less easily described. Kind of like greasing bullets that Hatcher describes as a practice that occured with initially great success in the '20's, that is, great success till trouble started cropping up with overpressure indications and some wrecked guns. Eventually the practice fell from favor as bullet design improved. Personally, I believe we have many powders now that reduce or eliminate the necessity for fillers in most cases as a general method for developing reduced loads.

Since there is little load data printed by the powder companies recommending the use of fillers, that means an open forum is where the info is, and I do not want to be involved in recommending something I may describe improperly or not quite adequately, that's all. Since there IS more and more reduced load data being produced by the component companies, that is the direction I personally prefer to direct folks inquiring of the subject.

Another note of a historical nature FWIW: various fillers and wads were used in British military production of "Short Range Practice" Marks II, III, IV .303 ammo as identified in Labbett and Mead ".303 INCH". And IIRC, US arsenals produced "guard cartridges" in various calibers in the early 1900's, some of which used cotton wool as a filler, tho I cannot remember the source for that offhand. I know some of the reasons they were discontinued, but cannot remember the "safety history" of their use or if safety considerations were part of the reasons for their discontinuance.