I've got a flat horn. I got it from one of the guys here on the forum a few years back.
I've hunted with it a few times and I like the way it tucks in high and tight on / over my bag....and the spout is always up, no matter what, and I do like that part.
I'm not sure if I like it better than a round horn, but so far I find myself really liking this little thing.
I'm also not sure how much it holds, but I'm guessing 8 or 10oz. of powder. I remember when I filled it the first time I was thinking, it held a lot more powder than I had expected....I'm guessing I can easily get about 60/70 shots using FFFg at 70gr which is plenty of powder for a hunt.
( I'll have to empty it and actually measure how much it does hold....now that you guys have brought this to mind.)
Here it is with an old, very beat up pouch I made sometime back in the 1970s......
You can also see part of my patch-knife that I made from a saw blade, which is good because it is flexible...that particular old knife has dressed out everything from Cottontails and a few Deer to an Cow Elk, and serves quite well as my dinner plate knife too....lol
Even an old blind hog finds an Acorn every once in a while.