Simple fact: Bottle neck cartridges are no problem whatever for using fillers. If fact use of fillers greatly improve uniformity of ignition and subsequent velocity when loading cast bullets in modern bottle neck calibers, especially cartridges with a high volume to caliber ratio like the .22/250. Same with reduced velocity jacketed bullet loads. There have been several excellent articles and guides on using fillers with modern calibers, especially those published in Handloader magazine several years ago by handloading experts. In earlier post in this thread I simply stated "dacron" assuming any knowledgeable handloaders seeing this thread would pick up on it and expand. Apparently there were none, so I'll explain: Dacron is a polyester fiber used in pillow stuffing, etc. I tiny wad of it is easy to insert in a narrow necked case and expands to fill the empty space occasioned by use of reduced loads. It is virtually weightless in these small case-filling amounts, adding nothing to the charge like ,say, cornmeal, etc., and consumes cleanly with the powder burn. Very convenient to use, especially with bottle neck calibers. (But pieces of toilet paper for filler, sorry, but whatever "expert" suggested this is way behind the learning curve.)