How a vintage BB shot tube works
by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- Shot tube is the true barrel
- The shot tube
- What keeps the BB from rolling out the barrel?
- A spring!
- That’s all, folks
Today’s report was suggested by a question from reader 45Bravo, who asked, “How does the shot tube retain the BB then, if not by a magnet?” That’s a good question and I know if one person wants to know there are hundreds of others who haven’t asked, but also want to know.
Bear in mind that when the Red Ryder first hit the market around 1939, there were no rare earth magnets. They came along in 1966, and have been advancing ever since. So the question remains — how do the shot tubes of older BB guns work?
They work by gravity. They work by the same principal that the magazine of the first Gatling Gun used, back in the late 1860s. Gravity pulls the cartridges (and the BBs) down, so all that’s needed is a chute to guide the ammunition to the loading/firing mechanism. It’s a little more complex than that, but not much. And it’s all mechanical.
Shot tube is the true barrel
In a vintage Red Ryder like the one I recently tested for you, the shot tube is the actual gun barrel. What looks like the barrel, and what most people refer to as the barrel is a sheet metal jacket that surrounds the shot tube and forms the outside of the BB magazine. It isn’t really a magazine, though. The shot tube performs that function. The barrel jacket is really more of a BB reservoir that stores the BBs until it’s time for gravity and the shot tube to take over.
The shot tube is inside the barrel jacket. The gun is fired in this drawing.
BBs are shown in the gun. They are evenly distributed around the shot tube, but I have omitted them so you can still see the tube.
In this drawing, the gun is shown cocked. The plunger has been withdrawn during cocking, and the air tube backed up far enough to permit one BB to enter the barrel. When the cocking lever was released, the plunger went forward a fraction of an inch, pushing the BB in the barrel up past the opening in the side of the shot tube breech and closing that hole to any additional BBs.
The shot tube
Now that you know what the inside of the BB gun looks like, let’s examine the breech end of the shot tube of a vintage Red Ryder. This is the shot tube from my gun that I reviewed for you recently.
This view of the shot tube shows the organizing chute the BBs roll down inside the barrel jacket. The barrel jacket itself forms the outside of this chute. The flange at the right side of the picture is wide enough to prevent BBs slipping past, and it is angled to start them rolling down the chute when the gun is cocked. The hole at the breech (arrow) is large enough to admit just one BB when the air tube is completely withdrawn during cocking. When the lever is relaxed, the air tube moves forward a fraction of an inch, preventing a second BB from entering this hole.
What keeps the BB from rolling out the barrel?
Okay, we now understand how BBs are fed by gravity, one at a time , to the breech of the shot tube. But once inside, what prevents them from rolling all the way down the barrel when the muzzle is depressed? That was 45Bravo’s question.
On the opposite side of the shot tube breech there is a wire spring whose end is curled and sticks through the breech into the barrel. It protrudes far enough into the barrel to prevent the BB from rolling forward, until the air tube pushes it past during firing. So the loaded BB rests between the end of the air tube and this spring when the gun is cocked.
The wire spring protrudes into the barrel (arrow) to stop the BB from rolling forward. The other end of the wire at the right does not protrude into the barrel. A simple but effective way of holding the BB until the gun fires.
That’s all, folks
And that is how the shot tube of a vintage BB gun works. Once you understand it you see the necessity of elevating the muzzle of the gun during cocking, but the design of the gun forces a shooter to do that. The gun was too difficult to cock any other way.
We have looked at vintage BB guns from several different viewpoints in this historical series. Today’s report completes the journey into how they work. Thank you, 45Bravo, for posing such an interesting question.