Well the one in my picture is from Track of the Wolf. They have a wide selection of good looking ones. Ebay can also be a great source to get one for not much money. I recommend you get one with one or two pockets inside to keep things better organized. Shooting bags and horns are a hobby unto themselves and a number of people make their own. I just buy, though. My horn is from October Country, as is the solid brass range rod in the picture, both are excellent and very high quality. When buying a horn, steer clear from the super cheap ones. They might be made in China and probably leak and let air and moisture in to contaminate the powder, or are constructed improperly to handle an explosion in the event they do explode. A properly made horn is watertight and made so the plug in the rear can easily blow out from the pressure of the explosion. As for what I keep inside my bag: I try to keep things as authentic to the 19th century as I can, at least to an extent. I keep a ball bag, tools for my ramrod (ball screw, worm, brush for chambered breech), homemade shooting patches (cotton drill cloth and mink's oil), cleaning patches tied into bundles to keep them together, a nipple wrench, capper, short starter, and on the strap of the bag, a fixed 90 grain powder measure and a nipple pick. I also source straight grained hickory ramrods from October Country and cut and finish them for the rifle, adding a button jag to the end so I can swab between shots and load with the under barrel rod in the field, as well as clean the gun with it too. If I were taking the gun out for an overnight or multi day trip, I'd take along a couple more bundles of cleaning patches, a small rag, and a small container of bear's grease for cleaning purposes. The accouterments are part of the fun of black powder shooting.