Was tinkering again. Doing a little R&D for an ultralight barrel using 24" long Poly Carbonate MAILING TUBES. The trick was to mount it as a barrel onto the cannon/RPG. Tried heating and flaring the end and it worked! It didn't split or damage the tube during firing. A little fragile but makes the barrel weigh NOTHING compared to PVC barrels.
Nerfs fit snugly inside the tube so that solved my problem of needing an Nerf detent to keep the Nerfs with trimmed fins from sliding down the barrel onto the ground. Thought it might make a good Nerf detent all by itself by just lining the breech of my RPG barrel with it. A 7" piece, the flared end, and some Super Glue to keep it from rattling out.
That got me to thinking that maybe YOU GUYS might want to know about it as a CARTRIDGE to hold Nerfs that could be gravity fed down a magazine into an autoloader or bolt action RPG. Easier to carry etc. So here ya go.
To make the Flared end I just extended 3/16" of the mailing tube past the end of a piece of schedule 40. Heated it with my heat gun until it got soft and it doesn't take long. Thin Stuff. Rolled the edge with my finger covered with a light cotton work glove for insulation. To get a SMOOTHER edge I should have just flattened it with a piece of board or just stuck it upside down onto a flat surface until it cooled completely.
You can see that is slides FREELY inside schedule 40. You could use that flared end for two things. To keep it from becoming a projectile along with the Nerf AND a perfect ridge for an extractor pin not unlike your bolt action rifles to eject the empty cartridge after firing. Ejecting Cartridges have been troublesome for many in the past. Just flip it out with an extractor pin and keep on firing.
Does that give you guys some ideas? A gravity fed magazine. A shotgun type feed under the main barrel with a spring feeding up into the breech. A hand fed bolt action? An ultralight belt FEED for a Mech Warrior or Walking Tank?
If I was going to make a Nerf cartridge, I would consider making it shorter than the Nerf. Flush in the back at the fins but extend forward to just past the widest part of the Nerf. That way the TIP of the Nerf would guide it into the breech and align the end of the mailing tube to slide into the PVC. If you chafered the INSIDE of the PVC, I think you would have minimal jamming issues on the feed going IN.
Now remember, I HAVE used this as a RPG barrel. It WILL hold he pressure so that may mean you don't have to slide this cartridge ALL the way into the barrel. Just far enough to seal the end of the Cartridge by the barrel. A tip for you guys Quest for Cannon Rate of Fire. The shorter distance it has to travel, the less time it takes to get there...