You know the credit card commercial tagline -- "So what's in your wallet?"
I was wondering something similar: "So what's in your bum bag?"
This being my first season in WFTF, I was dragging around my bum bag, knee roll and 15-pound rifle this past weekend for a 70-shot contest.
After I got home and was sort of totally exhausted, I kinda wondered if I could stand to lose some weight ... from my shooting kit, of course.
(Heavens, I'm not giving up IPA or Cheez Whiz for nobody!)
Asking around the forum, there was no consensus on the lightest, bestest filler for a bum bag.
(No consensus on GTA? Gee, insert a Shocked Face here.)
Through blind luck, I Googled up a sheet of common material weights compiled by the folks at Tapco who manufacture and sell dandy big machinery for the huge grain silos you see all through the Midwest.
You can download it here http://www.tapcoinc.com/content/product_data/Tapco_Catalog_09_p88-94.pdf
Here are a few of my favorites for comparison. Each weight is for one cubic foot:
Ground recycled rubber -- 23 to 50 lbs. (This is the filling in my kneeling roll.)
Ground corn cobs -- 17 lbs. (This is what I have used in my bum bag up to now, Hartz Mountain small animal bedding.)
Granulated cork -- 10 lbs.
Navy beans -- 48 lbs.
Dry guano -- 70 lbs.
Dried sewage sludge -- 40 to 50 lbs.
I also researched Buckwheat hulls from another site -- 9 lbs. per cubic foot
So there ya go.