Hey Devildog, thank you for taking the time to add your input here, it is appreciated. In our testing, and independent testing, the exposed zipper has been holding up very well when the bungee is wrapped around the corner loop like is demonstrated in the video. I have thrown the bag on the ground repeatedly and the zipper has stayed closed very reliably. The zipper we use is the largest that is available, number 10 zipper chain.
I originally experimented with a double velcro flap to keep from using a zipper. This turned out to be very time consuming and difficult to turn right side out. I had originally given the zipper a passing thought but disregarded it as a weak link that wouldn't work. I was on my second day of working on prototypes when my sons girlfriend Elena, who works for us, asked if I had tried the zipper. I was getting frustrated with the velcro idea and said "what the heck, let's see how it turns out"
The zipper turns out to be the easiest method I found for accomplishing what I wanted the bag to do. Easy to make, as economical as possible to make, easy for the end user to use, so far is holding up to abuse very well. The velcro took so much time to make look acceptable that the cost was going to be higher than what I wanted to list it at. I was also not liking the velcro idea as it was adding bulk to the bag that I didn't like either.
ArmyJerry, we have received quite a bit of support for the current fill we use. I'll start another thread posting some pictures I've made with different size bags so I can get some feedback from folks.
The case, is our rifle cover. Here's a link to the site. Frank shot a video of it when he was down and we'll have it on the site as soon as it's ready. I'll also have some more pictures uploaded to the site in the near future as well.
TAB Rifle Cover