Design an airgun

by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • Air gun?
  • What about pneumatics?
  • Can you build a spring-piston gun?
  • Keep it honest
  • Contest?

This report will be different than usual. Today I’m challenging you to design an airgun that we readers can build!

I’m guessing it will be a BB gun, but it doesn’t have to be. I’m guessing it will be a smoothbore, but again, it doesn’t have to be.

Air gun?

When I say build an airgun, it doesn’t have to work with compressed air. The Daisy 179 pistol is considered an airgun, but in reality it is a catapult gun.

Daisy 179
Daisy’s 179 is really a catapult gun.

The Hodges gun of the early 1800s is also a catapult gun, and a powerful one at that. It is said to have been capable of killing medium-sized game such as feral hogs. read more


Sharpshooter pistol resurrection: Part 4

by Tom Gaylord
Writing as B.B. Pelletier

Sharpshooter pistols
The Bulls Eye pistol (left) came first. Manufacture started in 1924 in Rawlins, Wyoming. The smaller Sharpshooter pistols at the right were made in Rawlins until sometime in World War II and then manufacture moved to La Jolla, California in 1946.

Part 1
Part 2
Part 3

History of airguns

This report covers:

  • Learned a lot!
  • Velocity
  • Three guns to test
  • Plain Blue pistol from La Jolla
  • Black DeLuxe pistol from Rawlins
  • Curses! — foiled by eBay
  • Summary

Here we go! This is probably the final installment of this series that started several weeks ago when the grand nephew of John Beckwith, George, sent me some carriers for Sharpshooter pistols that his grand uncle had given him. With one of them I was able to resurrect a Sharpshooter pistol I have owned for many years. Its plastic carrier broke and the gun has been silent for a long time, but thanks to George it’s up and running again! read more


Sharpshooter pistol resurrection: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

Sharpshooter pistols
The Bulls Eye pistol (left) came first. Manufacture started in 1924 in Rawlins, Wyoming. The smaller Sharpshooter pistols at the right were made in Rawlins until sometime in World War II and then manufacture moved to La Jolla, California in 1946.

Part 1

History of airguns

This report covers:

  • Cleanup
  • Companies that made and sold Sharpshooter pistols
  • Odd guns
  • Accuracy
  • Adjustable sights
  • Hard to get groups
  • Summary

Cleanup

Today I take a turn from my usual format. This is Day 2 where I normally report velocity, but instead of that I’m going to begin with accuracy. The reason for doing that is because when the pistol is adjusted for accuracy the velocity is affected.

Sharpshooter adjust rail
This screw pulls the two halves of the sheet metal together, pushing the front of the guide rail upward. That tightens the fit of the carrier on the rail — affecting both accuracy and velocity.
read more


Sharpshooter pistol resurrection: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

Sharpshooter pistols
The Bulls Eye pistol (left) came first. Manufacture started in 1924 in Rawlins, Wyoming. The smaller Sharpshooter pistols at the right were made in Rawlins until sometime during World War II, and then manufacture moved to La Jolla, California in 1946.

History of airguns

This report covers:

  • New parts!
  • My Sharpshooters
  • Unmarked guns
  • What the launcher does
  • How accurate?
  • John O. Beckwith
  • A full report
  • Launchers/slides/carriers are available
  • Summary

New parts!

A month ago I was contacted by reader George, whose great uncle, John Beckwith, produced the Sharpshooter pistols in La Jolla, California. George had read my Part 1 of the Sharpshooter report that was published in September of 2018 and he noticed what I said in one of the captions.

metal Sharpshooter launcher
The sliding launcher is what flings the shot from the pistol. The older Sharpshooters have metal launchers like this one that last for decades. This one is about 76 years old and still works fine. That flat metal piece on the right is the sear that also opens the in-line magazine to allow one shot to fall into the launcher when it is pushed up by the launcher.
read more


Johnson Indoor Target Gun: Part 5

by Tom Gaylord
Writing as B.B. Pelletier

Johnson Indoor Target Gun
The Johnson Indoor Target Gun is a catapult BB gun that was made in the late 1940s for youth target practice.

Part 1
Part 2
Part 3
Part 4

A history of airguns

This report covers:

  • The test
  • First shot
  • Second shot
  • Adjusted down again
  • Rubber band broke
  • Now for a group
  • Proof of the pudding
  • Summary

Well, all the work we did was to get to this point. Today I shoot the Johnson Indoor Target Gun for accuracy.

The test

I shot at a target about 10 feet away. I was seated and used the UTG Monopod as a rest.

Since these BBs are only moving 126-129 f.p.s., or so, I used an aluminum foil target like the one I made for the Sharpshooter catapult gun test. We know slow-moving balls will penetrate aluminum foil readily. The target was backed by a cardboard box that stopped every BB, and then sent them back at me. More work is required on the backstop to catch the BBs successfully.

I only used a single type of BB for this test. There could be a difference in accuracy, I suppose, but it seems to me that catapults are far more forgiving of what they shoot. So, I chose Air Venturi Steel BBs.

I shot only 5 shots instead of 10. When you see the target you’ll understand why. The aim point was at 6 o’clock on the dot drawn on the foil. Let’s get started.

First shot

The first shot went high, so I took a picture of the target to show you. Fortunately the Johnson has adjustable sights.

Johnson first shot
The first shot (long arrow) hit considerably above the aim point (short arrow).

Johnson sight
The rear sight adjusts for elevation. Unscrew the knurled disk and slide it up and down. The first shot was with the sight set on the top line (blue arrow). For shot two the sight was set as seen here. Shot three was with the sight set on the red arrow line.

Second shot

Shot two was to the right and not that much lower than shot one. I could see the rear sight needed to be lowered a lot! That’s why I showed all the sight settings in the picture above.

second shot
As you can see, shot two moved to the right but not down by much.

Adjusted down again

This time I really dropped the sight. And it paid off with a shot through the dot I was aiming at! The picture is really dark, so I lightened it.

bullseye
Nailed it on shot three.

Rubber band broke

On this shot the rubber band broke, so I had to make a new one. I don’t think it affected the accuracy of the shot, however, and the shots that follow will confirm that.

Because of all the work I had done in the previous tests I knew exactly how to replace the rubber band. It only took five minutes before I had the gun back up and running.

Now for a group

Since the last shot was on target, I decided to just shoot 4 more shots without changing anything. Even though the rubber band had to be replaced, it had no affect on the sights. The gun was still sighted-in.

Four more shots went downrange. Shot 3 was a called pull to the left. When I was done I had a tight little group to show. Five shots had gone into a group measuring just 0.358-inches between centers. Sure, it was only shot at a distance of 10 feet, but that’s the nature of this gun.

group
Five BBs went into a group measuring 0.358-inches at 10 feel. Shot number three was a called pull to the left. read more


Johnson Indoor Target Gun: Part 4

by Tom Gaylord
Writing as B.B. Pelletier

Johnson Indoor Target Gun
The Johnson Indoor Target Gun is a catapult BB gun that was made in the late 1940s for youth target practice.

Part 1
Part 2
Part 3

A history of airguns

This report covers:

  • Research
  • Cutting trouble
  • Sloppy cutting
  • It worked — sort of
  • What to do?
  • Experiment over?
  • Too much power
  • Summary

Today I will try a different kind of rubber in the Johnson Indoor Target Gun. Several readers who are more knowledgeable than me about slingshots recommended I try Theraband Gold. It is one of the types of elastic that’s favored by catapult users and makers around the world. I watched a You Tube video of the Slingshot Channel titled, The BIGGEST slingshot EVER. The builder uses Theraband Gold to launch a bowling ball into a Mercedes car repeatedly, destroying it.

Research

I bought 6 feet of Thereband gold rubber on Ebay, a rotary cutter to make clean cuts and a cutting mat for this project. I used the data from Part 3 of this report as my starting point, simply because there was nothing else to use. Maybe someone has done what I am about to do before, but I have never seen it in print.

materials for Johnson gun
The rotary cutter is to cut the Theraband material cleanly.

Cutting trouble

Right off I noticed that the cutter had a mind of its own. I should have used a seamstress’s plastic cutting guide, but I have already spent a lot of money and I wanted to get on with this test. I needed it quick and dirty and that’s how I got it.

Theraband ready for shooting
Here is the band I made to shoot. As you can see, I got sloppy in the cutting. I will explain why in the text.

Sloppy cutting

Once I figured out that I wasn’t going to cut the band straight, I gave up and cut it freehand. I wasn’t looking for a final solution. All I wanted was to see if this was even possible. So any band I made would not be used in a final test. I just wanted to see if this worked.

It worked — sort of

Well, it worked, and then again, it didn’t, I installed the band and shot the gun but it was extremely weak. Cocking was normal and the launcher caught the band when it went forward, but I didn’t bother to chronograph the shot because it was way below what we have seen. As a guess it was in the 50-60 f.p.s. range.

Johnson launcher
The band has to fit inside the groove in the launcher (arrow) or it won’t work.

What to do?

Well one band wasn’t going to do anything, so I wondered about multiple bands. They would be more powerful, but there would be a problem. The rubber band has to fit into the groove that’s in the launcher in order for the gun to work. Surgical rubber tubing is great because it fits into the groove very well when it’s stretched, but a flat band like the Theraband has to be stretched very thin to fit in. If it’s not all the way in, it can slip out on firing or even when the gun is just cocked and left alone.

 

Nevertheless, I wanted to know, so I cut three bands of equal length and made a loop at each end of all three.

Johnson gun three bands
I cut three bands of equal length from the Theraband material.

Johnson gun three bands looped
I then made a loop at each end of the three bands.

The bands are uneven, but all I want is to see whether this approach even works. The bands went into the top cover of the gun, but they slopped over the anchors and when I cocked the gun, they didn’t all fit into the cocking groove on the launcher. It was a disaster!

Then I took the three bands apart and used the two smaller bands together in the same way. This worked — sort of. I could cock the gun, but when I shot it, the bands popped out of the launcher groove and the shot was weak. It registered 86 f.p.s. Okay, that doesn’t work.

Experiment over?

I thought this was the end of it and I could install another surgical tube and be done with it, so I did. Since I knew the tube had to start out 7 inches long, there was no wasted time. The velocity was 127 f.p.s. which is very close to the best velocity I got in the Part 3 test.

I thought this experiment was over. But that evening I thought about it some more and I wondered whether twisting the flat Theraband might be a solution. It’s flat to begin with, and if I twist it many times would it roll into a cylinder that might work better?

I used the widest of the three bands I had cut before — the band I had removed when I tried two bands. As you can see, a wide band can be twisted thin.

Johnson gun band twisted
After anchoring one side of the band I rolled it to one side, twisting it into a cylinder.

It worked! This time the band loaded into the launcher’s groove and also allowed the gun to be cocked. The velocity was 129 f.p.s., which is as fast as I have shot so far. That is a good place to stop. I have no doubt that a higher velocity can be reached. I think 160 f.p.s. or even a little more might be possible, though I doubt 200 f.p.s. can be broken. I even cut a wider piece of Theraband Gold to test whether a special shape of rubber might help.

Johnson gun custom band
I cut this band and even started installing it. read more


Johnson Indoor Target Gun: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

  • Johnson Indoor Target Gun
    The Johnson Indoor Target Gun is a catapult BB gun that was made in the late 1940s for youth target practice.

Part 1

A history of airguns

This report covers:

  • Operation
  • Cocking
  • Trigger
  • Serendipity
  • Pat is not pending
  • Adjustable sights
  • Repeater
  • Summary

I was going to write about something else today, but the response to Friday’s report convinced me to stick with the Johnson. Several of you said that you enjoyed the detailed photos. Today I will tell you about how the gun is constructed and how it operates, plus some special features. Grab your coffee cup and let’s go!

Operation

The Johnson gun is a catapult gun, and in Part one I showed you the broken surgical tubing in my new gun. Now, take a look at a gun with tubing in working condition.

Johnson rubber working
This is how the rubber is supposed to look when it’s properly installed. The ends of this surgical tubing are held together with small cable ties. We are looking at the inside of the top cover of the gun.

Now allow me to show you how access is gained to that rubber. The top is pulled up out of the way for easy access. To release it the two spring steel “ears” in the front of the gun are spread apart and the top is raised.

Johnson top closed
This picture shows the top closed. The two spring steel “ears” on either side of the top are what hold it in place. The front sight is a post on a wheel that can be turned to move the post from side to side.

Johnson top open
Here, the top has been pulled up out of the way. Lotsa surface rust on this older gun, no? This is not the one I’m writing about.

Johnson top up
The top is flipped up. The rubber you saw before is in the top (blue arrow) and the launcher is at the rear of the bottom section (yellow arrow). read more