Okay, I haven't gotten to do a lot on the Hi point project due to being preoccupied with work, but I've narrowed the drum issue down a bit. I've seen where guys have successfully used these drums on their transferable Mac 10/11 sub machine guns, and a lot of the initial issues are friction and getting the magazine to the right angle in relation to the drum. The thread about Suomi conversion for Mac's can be found here over on Uzitalk. Lots of good information there, but a Mac has a thicker magazine than a Hi Point, with sturdier feed lips and more room to maneuver. Now, after thinking about the situation, a person could easily make a magazine that would fit the mag well and be not only a thicker material, but have reinforced feed lips on the mag as well. You could also machine a magazine out of solid stock that would actually be an integral part of the rifle. What I mean here is a "magazine" that drops in through the top of an dissembled rifle, and has a drilled and tapped base that would allow a drum magazine catch assembly to be bolted on to the magazine. This would allow you to use multiple drums. All that would be necessary would be for the user to disassemble the rifle, drop in the "magazine", bolt it to the rifle on the inside of the receiver, reassemble the rifle, attach a Suomi drum, hit the drum spring release, and start shooting. This would alleviate my having to deal with the random good/bad drum selection that most retailers have in trying to complete a whole-unit drum and magazine assembly.
This integral magazine design could work, I think, a lot better than a stand-alone unit.
Now, the stand-alone unit might work well, as long as I can make a thick enough magazine so the feed lips don't bend under spring pressure. I have read of several people trying to build a Suomi drum arrangement for their Hipoint, but none of them tried it using a different magazine than the factory Hi Point mag. I will likely start there.
Now, to add some more fun to this, I was taking some measurements and looking at the internals of the carbine the other day. I looked across the table from the rifle, and there was a double stack 9mm mag for my Springfield XD. It turns out that there is not a whole heck of a lot of difference between the width and depth of the factory Hi Point mag and the XD mag, and the angles are ~somewhat close. I need to go buy a Glock mag and see if it is any closer to the same angle. Now, since the rifle is set up for a single stack mag, the stock is as well. The stock can easily be cut for clearance, but the problem lies a bit higher up, as there are two things in the way of a double stack mag; the mag release and the trigger transfer bar. Neither of these is that big an obstacle to being moved back 1/4" to allow a double stack mag to fit. This actually looks to be an easy-ish conversion to do, if you have the right tools. It involves building a new mag catch and likely a new transfer bar, but that's no issue. Everything else in that spot is polymer plastic, and could easily be cut and moved, or a new, wider piece machined out of sheetmetal and attached to the receiver. This would allow for two things, 1. Double stack magazines, and 2. an easier Suomi drum conversion using thicker, more durable XD or Glock mags.
EDIT: The area of the receiver I was referring to is not actually polymer plastic, but cheap pot metal instead. This doesn't change much, but I wanted to clear the air.
I am going to try the most obvious thing first, and build a new sheetmetal magazine and attempt to attach it to a Suomi drum. If this works flawlessly, then it is worth considering building a few more. If I can convert the carbine to double stack mags, though, I really think that would be the best approach. People in ban states could use the very-reliable-and-inexpensive 10 round Glock mags (or XD, whatever), and people in free states would have their choice of options, a 10 round mag, a 16 round standard capacity mag, a 32-33 round larger capacity mag, or even the Suomi drum for the truly twisted individuals that like turning money into smoke and noise.
So, hopefully this week will be a good week to start. First item up is to make a new magazine on my sheetmetal brake, then attach it to the drum.
Keep an eye out for this, as I refuse to stop on this project until my 200 dollar carbine has the ability to hold and shoot more than 10 rounds in one sitting.