I don't particularly understand this distrust of gravity clips. Magazines and springs are only a recent development and everything prior to those involved gravity feed from a deodorant clip, cassette tape clip, or hopper.
I want to be able to reload with just my left hand, something not easy to do if you have to hold a follower down while loading darts.
Keep in mind that this gun does not have a breech made from brass or plastic tube. The darts are simply ram-loaded into the back of the barrel, and the ram then seals the end of the barrel.
It's not like the gravity clip is 12 inches tall. To fit 6 rounds it only has to be 3 inches tall. The sights will be on the sliding door on the top of the clip.
Well, I wasn't really around in those classical days of pure gravity feeding. I guess these modern times have made me greedy.
If I remember correctly, there are (real) bolt-action rifles whose fixed, internal box magazines can be loaded by (basically) just pushing the cartridges in – once the bolt is open, of course. It seems to me that , if you are able to build a system similar to such bolt-action rifles, you should be able to pretty much just push darts straight down into the internal box magazine any time the breech is open. And I don't think that it would be too difficult to reproduce, really, considering the style of your breech. If you need, I might be able to get some pictures...when I visit home in 2 weeks. I hate being living at college: I can’t get anything Nerf-related done here except think.
Of course, the ability to create something like the above system is dependent upon whether or not your bolt stays open (or, can be kept open) for a significant length of time. Does it? If not, then I think the above is pretty much impossible.
If you want to stick with the gravity clip but require a follower, you could simply have the follower lock in the “loading position.” The process would be something like:
1. Push follower up and then slightly forward (to lock at top)
2. Load darts through use of a side port.
3. Pull follower back slightly to allow it to drop onto the darts.
As far as aiming, I had originally not noticed how tall this thing is (when compared to the level of the barrel) even without a magazine/clip on top. In my mind, I was picturing an MP5 with several inches of magazine sticking up off the top. My mistake.
By the way, that breech is amazingly simple yet brilliantly unique. It was a big "duh" moment for me. I mean, seriously: It's really just a typical (real) bolt action...only it's moved forward and back by air pressure. Is this how the ABP5k's breech worked, too? I'm afraid I never fully understood its inner workings...