My work on Yoko's rifle is definitely not finished at this point, but here's what's happened so far. I will not be making a tutorial about this, mostly because I can't really remember or even begin to explain exactly what I did. Click on photos to enlarge them.
I began with a few cardboard tubes left over from rolls of fabric, gift wrap, and other miscellaneous things (no toilet paper rolls though, haha!). One roll that I had was 4'11" long and was thinner than the rest. I had another roll that was the same diameter, but only 1'7" long. I cut 6" off of the shorter tube and hot-glued it to the longer one, making it 5'5". Looking back, I should have made it 5'3", but I really had no idea what I was doing (still don't!) and just sort of guessed how tall I wanted it to be. (I'm 5'4", by the way, and about 5'6" in my Yoko boots.) I originally wanted my rifle to be about an inch shorter than me, but oh well.
I didn't really have a plan for scaling here, I just guestimated how big things should be and went at it. It seemed to work out, thankfully! I think some parts are a little wide (I actually think the entire thing is a little bigger than it should be), but it's at least proportional to itself.
A majority of the pieces are cardboard, but for curved areas and some places where something attaches to the barrel (the main tube), I used craft foam.
I had, and am still having, difficulty with attaching the scope. In the anime, the scope is attached by four thin metal pieces, which doesn't really translate well into cardboard. They bend and have broken a couple of times, so the scope leans to the side sometimes. I'm not entirely sure what to do about it, but it does stay upright for photos.
The back end of the scope (where someone aiming to shoot would look) is a solid piece of cardboard painted green with the cross-hairs drawn on with pen. Of course I wanted to make it so that you could actually look through the scope, but I didn't have the right materials. Also, with the design of the scope, you wouldn't be able to aim properly anyway without some inner workings, which I am not up to the task of making.
The front of the scope is also a solid piece, the green is a piece of a 3X5 index card painted green. The shadows in the photo make the edges look rougher than they are, though they are pretty rough on their own. I'm not sure how to fix that or what I could have done differently. Cardboard is rough and difficult to cut.
The end of the barrel is indented and sealed off with orange craft foam. Unfortunately, I'm going to have to add craft foam to stick out one inch from the end of the barrel so that it can be seen from the side in order to comply with most conventions' prop firearm rules. Of course I'm disappointed that it distracts from the realism of the rifle, but I do recognize and appreciate that it's for my own safety. I would rather have a little orange piece on the end of my rifle than have the convention not require or check this and end up getting shot. Also, it's a small price (if you want to even call it that) to pay for being able to show off my hard work without issue.
Now for the fun part, the rifle comes apart for storage and transportation! I went through a few methods to make this work, and I am extremely happy with how it turned out. I knew from the beginning that I wanted it to come apart at a certain spot, underneath one of the ridges so that the seam wouldn't be seen. Originally, I thought that I could hold the two pieces together with magnetic snaps that I had originally bought for Yoko's belt. (I only needed one for the belt, and they came in a package of three.) However, the end of the barrel was too heavy. I tried two magnetic snaps, a regular snap, Velcro, and various combinations of these things, but nothing seemed to work.
I'm still not sure how I came up with this, but I somehow found the perfect solution. I cut open one of my larger cardboard tubes and started rolling it in on itself, making it sort of spiral inward and get smaller. Once it was small enough, I put it halfway inside of the main part of the rifle and put the rest of the barrel on the other end of it. Basically, the smaller tube goes inside of the barrel where the barrel comes apart. Hopefully the picture explains.
I chose to paint the ends of the inner tube orange/pink along with the open ends of the rifle barrel just in case I end up taking it apart at a convention for some reason. California law states that the ends of prop firearms must be painted in a bright color. If I take apart the rifle, the back end looks like a complete gun on its own, and I didn't want to cause a problem, so I painted the end and inside pink in a way that can't be seen when it's fully assembled, but can be seen when it's taken apart. I painted the ends of everything else pink just for good measure.
In one photo, you can see some ink marks on the tube that goes inside, it's a star that I drew in blue permanent marker to differentiate that piece from scraps that I had lying around. I actually did this to almost all of the pieces that went into the rifle, and I highly recommend it. Before I figured out this trick, it was difficult to tell my some of rifle pieces apart from the scraps and finding things took much longer than it should have. Since the paint is black, it covers it right up.
I painted the rifle in two pieces. First I tried spraypaint, but it didn't give enough coverage. After a couple of layers of spraypaint, I ran out (it was an old can that I found in the shed), so I switched to hand-painting with acrylic. It gave a lot better coverage, but it isn't as shiny, so I'm hoping to get some kind of spray to give it some shine.
So as it stands, I still need to add the pink stripes on the barrel, the yellow stripes on the end, the orange tip, the strap to carry it, another coat of paint (in some places), and a coat of gloss. However, I feel like a majority of the work is finished, and certainly the most difficult parts of the work are all finished. Hopefully next time I want to take it somewhere, I won't have to rush to finish it.