Pellet calibers — why .20?: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

Part 1

diabolo pellet
The diabolo pellet exists in four smallbore calibers.

This report covers:

  • History
  • Back to Sheridan
  • Early success — sort of
  • Why .20 caliber?
  • The next speedbump
  • Boom
  • Bust
  • Summary

Today we take a look at the .20 caliber that is also popularly labeled as 5 mm. There were Quackenbush airguns in the late 19th century that were made in .21 caliber and Crosman made some gallery airguns in .205 caliber, but the true .20 caliber didn’t exist until it was created by Sheridan in 1947.


According to Ronald Elbe’s book, Know Your Sheridan Rifles and Pistols, 2nd edition, copyright 2018 by Ronald E. Elbe, the 5mm pellet (and airgun) existed in Europe prior to the launch of the Sheridan model A (the Supergrade) in 1947. This is the first time I have been aware of that fact. To the best of my knowledge, only the Zimmerstutzen parlor rifle existed as a 5mm, and that size was at the high caliber range of the rifle. It would be a new ball size 21 or an old ball size 17. But a zimmerstutzen is a firearm by the strictest definition, so I need to find out more about the existence of these pre-Sheridan 5 mm airguns. read more

Pellet calibers — why .177?: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

diabolo pellet
The diabolo pellet exists in four smallbore calibers.

This report covers:

  • Smallbore calibers
  • Before diabolo pellets
  • Birth of the diabolo
  • Ideal for plinking
  • Highest velocity
  • Velocity wars
  • Target shooting
  • Field target
  • Summary

Sunday while I was walking through the hall in my church a man stopped me and said, “You know a lot about airsoft? You’re the grandfather of airsoft?” He had been talking to our youth pastor who works part-time at AirForce Airguns and he was trying to remember what he’d just heard.

Most readers can guess my response, but once we were on the subject of airGUNS, he said he needed a good air rifle — something to use on pests. He told me that he was aware such guns cost as much as $100 or even $125, and what would I recommend?

What I would recommend is an education, but of course I didn’t say that. We have all been where he is now and we had to learn from someone! That started me thinking about the basics. A couple weeks ago I completed the series on How to mount a scope. There were plenty of basics in that series, but we also went into some of the more advanced principals. I thought that would be a good approach to use for pellets, as well. Let’s see where this goes! read more

What’s wrong with solid “pellets”?

by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • Diabolo pellet
  • The couch coach solution
  • Tradeoffs
  • Summary

Today’s report was engendered by yesterday’s report about the AirForce Texan big bore air rifle. Many of you have been discussing the advantages of solid pellets over diabolos

Today I’d like to look at this question a little closer. For starters, let’s call solid pellets what they really are, which is bullets.

pellet bullet
A diabolo pellet on the left and a bullet on the right. Let’s call them what they are!

In the 1880s pellets were either solid lead or they were lead with felt glued onto their bottom. In flight the felt caught the air and slowed the slugs down, keeping their nose pointed  forward. Just after the turn of the 20th century the invention of the diabolo pellet changed pellets forever. read more

SigAir Super Target: Part 4

by Tom Gaylord
Writing as B.B. Pelletier

Sig Super Target
SigAir Super Target (photo provided courtesy Sig Sauer).

Part 1
Part 2
Part 3

This report covers:

  • Adjusting the trigger — first
  • Adjusting the trigger — second
  • Accuracy
  • The test
  • RWS Hobby
  • Let’s examine that group
  • Hobbys again
  • Sig Match Pb
  • RWS R10 Match Pistol
  • H&N Finale Match Light
  • Discussion
  • R10 second try
  • Summary

Here we go, guys. Today we look at the accuracy of the new Sig Super Target single stroke pneumatic (SSP) target pistol. I’ll tell you right now that it’s accurate. But there is a lot more to cover today, so let’s begin.

Adjusting the trigger — first

Two words of advice. First — don’t adjust the trigger — at least not until you shoot the pistol a little. Second — if you do try to adjust it — GO SLOW! I know that most adjustable airgun triggers require a lot of adjustment before anything can be felt. This one is different. Please listen to BB.

I tried each of the adjustments for you and wound up removing the pull weight adjustment screw from the pistol. It wasn’t easy to put it back in again — it took many tries over several days to get it back. It passes through the trigger return spring that puts tension on the screw as you are trying to start the threads.

I thought I would be the only one to do that until a reader contacted me and said he had done the same thing with his Super Target. When he contacted me I had already replaced the screw, so let me show both you and him what it looks like when it’s in the gun correctly.

Super Target trigger
The big slotted screw on the left is the one that adjusts the pull weight. I turned it out too far and it popped out of the trigger. I then spent a lot of time trying to get it back. See the U-shaped wire spring that it passes through? That’s where the difficulty lies.

There is no hole through the triggerguard for a screwdriver to get on that screw, so the screwdriver has to come in from the side, yet still turn the screw straight into its hole. I even have short screwdriver bits and a sideways ratchet mechanism, but there isn’t enough room in the triggerguard for them.

Adjusting the trigger — second

Once the pull weight screw was back in place I found that all my “adjustments” were so far out of whack (my fault) that the trigger would not engage. So I cried, “Help!” to Sig and Ed Schultz sent me the following graphic.

Super Target trigger adjustments
This graphic is very helpful getting the trigger back into adjustment. The manual has a drawing that is clearer, but I like this one better.

The manual says to adjust each screw slowly (in small increments, like a quarter turn) and they mean it! I started out adjusting like an airgunner, which is to say more is better, but this trigger is very sensitive and needs those small movements of each screw. Also, adjusting one screw affects all the others, so check after each small adjustment. I went from a 15-pound pull (estimated) to a 2-pound pull in just five or six quarter-turn increments!

There! I have told you what to do and how slow to do it. If you get in trouble now, it’s your fault. I learned the hard way, as did one of our readers. Pay attention and you don’t have to.


Today is accuracy day and we are all curious how the Super target shoots. This will tell you whether this is the air pistol for you.

The test

This is a 10-meter target pistol so I shot from 10 meters. I shot off a bench with two different holds that I’ll describe as we go. I shot 5-shot groups so I could shoot more targets. And, since an optical sight cannot be mounted on the Super Target, I shot with the adjustable sights that comes on the pistol.

RWS Hobby

First to be tested was the RWS Hobby pellet. I shot this group with the bottom of the pistol grip rested directly on the sandbag. Because the Super Target has open sights I started right at at 10 meters and the first shot landed in the black of the bull. Four shots later and I had a 0.89-inch five-shot group at 10 meters.

Super Target Hobby group
From 10 meters the Sig Super Target pistol put five RWS Hobby pellets into 0.89-inches between centers.

Let’s examine that group

That group tells me two things. First — why do pellets string vertically like that? That’s right — because the velocity varies from shot to shot.

Next — why do wadcutter pellets tear target paper? Right, again. Because they are traveling slowly. Target paper is designed not to tear.

Now for the important question. The Super Target is an SSP. How do we speed up the pellets from an SSP and also make the velocity more consistent, shot-to-shot? We do it by pumping partially before pumping the gun completely — to flex and warm up the pump cup or other piston seals. I really want to know how this Super target performs so I shot a second string of Hobbys while warming the pump cup this way. I’m still resting the bottom of the pistol grip directly against the sandbag.

Hobbys again

This time I partially pumped the pistol five times. Then I loaded a pellet and gave it another partial pump that was quickly followed by a complete pump. I could hear that the pellet flew faster this time. After five shots I had a 0.57-inch five-shot group that exhibited zero tendency to string vertically. That’s a group size shrinkage of more than three-tenths of an inch by just changing how the pistol is pumped.

Super Target Hobby group 2
A second group of RWS Hobbys proved everything I said about velocity and consistency. Five shots are in 0.59-inches between centers at 10 meters. read more

IZH MP532 target rifle: Part 5

by Tom Gaylord
Writing as B.B. Pelletier

IZH MP532 single stroke target rifle.

Part 1
Part 2
Part 3
Part 4

A history of airguns

This report covers:

  • Got it!
  • Adjusted the butt
  • Fixed the rear sight
  • Windage adjustment
  • Sight adjustment
  • The test
  • Discussion 1
  • Discussion2
  • Discussion 3
  • Summary

Got it!

Sometimes BB gets it right, and today is one of those times. Got a lot to tell you so let’s get started.

Adjusted the butt

I’m shooting the newer (made in 2007) IZH MP532 today and the butt had been adjusted for maximum length of pull in an earlier report. This time I put it back to where it started, with the butt pad flush against the wood on the stock.

Fixed the rear sight

Part 4 covers the design and quirks of the rear sight in great detail, so read that to see what I discovered and what I did to fix it. I will show you one more thing today.

Windage adjustment

Reader Halfstep noticed in Part 4 that, like the elevation, the windage on the rear sight also adjusts both grossly and with precision. Two screws are loosened to slide it into the range where the precision adjustments can be made.

532 windage adjustment
Loosen those screws and slide the rear sight in the direction you need to adjust the strike of the round. This is the gross adjustment. The knob on the left side makes the precision adjustments.

Sight adjustment

I discovered while fixing the elevation that the precision adjustments don’t move the strike of the pellet very much — maybe two pellet diameters at 10 yards. So that gross adjustment that I showed in Part 4 is critical. And you want to get it into the range where you can adjust in both directions.

I found that a little of the gross adjustment moved the pellet a lot. It took three shots to get into the right range. When I did get it right the pellets were hitting slightly left, so I used the precision windage adjustments to correct.

The test

I shot five-shot groups with 7 different pellets from the MP532 off a sandbag rest at 10 meters for today’s test. Instead of talking you through each of them I’m going to show all 7 and then discuss them.

Remember, this rifle has an older pump cup, so I warmed it by pumping the rifle halfway about 20 times before shooting the first shot. Then I would pump it halfway and then all the way for every shot in the test.

I sighted-in with RWS Meisterkugeln Rifle pellets. Five of them went into 0.179-inches at 10 meters.

532 Meisterkugeln Rifle group
Five RWS Meisterkugeln Rifle pellets made this 0.179-inch group at 10 meters. How about that — a trime on the first group!

532 Sig Match Pb group
Five Sig Match Pb pellets made this 0.193-inch group at 10 meters.

532 Hobby group
Five RWS Hobby pellets made this 0.446-inch group at 10 meters.

532 Qiang Yuan Training group
Five Qiang Yuan Training pellets went intro 0.247-inches at 10 meters.

532 H&N Match Green group
Five H&N Match Green pellets went into 0.148-inches at 10 meters. read more

3D printing to the rescue!

by Tom Gaylord
Writing as B.B. Pelletier

Today’s report is written by blog reader New To Old Guns. We met at this year’s Pyramyd Air Cup, where he showed me the items you are about to see. I was impressed, and so was Val Gamerman, the president of Pyramyd Air. He gave his inventions to Val to take back to his office to evaluate, and he and I had already decided that a guest blog would be the right thing for everyone else. So, here we go!

If you’d like to write a guest post for this blog, please email me.

And now, over to you, New To Old Guns.

3D printing to the rescue!

This report covers:

  • The Sumatra magazine, the start of it all.
  • What is plastic printing?
  • How does the printer print?
  • Early success: the clip holder
  • Iteration is what makes this great!
  • Follow on success: belt and gun mounts for the clip holders
  • The power of 3D printing
  • Other resolved issues with the Sumatra
  • Summary

The Sumatra magazine, the start of it all.

Around 2003, I purchased the Sumatra 2500. It was a beast of a gun compared to anything I’d owned before. I was immediately smitten. But, it wasn’t long after opening the box and starting to use it, I found the first design choice I disagreed with. The clip is little more than a cylinder with 6 slightly tapered tubes and a pair of spring-loaded bearings front and rear providing centering force. There is nothing holding the pellets in the clip! That’s great, in that there is nothing to deform the pellets as they’re loaded and shot, but not so great because you can’t preload clips for field carry. The pellets just fall right out of the clip!

Sumatra clip
The clip.

To make matters worse, the muzzle of the gun has to be pointed upwards when loading, so the pellets don’t drop out of the clip then either. But, when the muzzle is upwards, the cocking lever can easily fall from being fully open, and it needs to be fully open to load the clip. The only mode the gun made sense was shooting with a bipod, either from a bench of the ground. Then the bipod would keep the muzzle up a little, and left you with enough hands to load the clip and keep the lever fully open.

That was how I used and enjoyed the gun, usually shooting prone off a bipod. It was a very deliberate, time-consuming affair, taking the 6 shots, open the ammo tin, reload the clip, close the tin, reload the gun, continue. There isn’t really anything wrong with that, but sometimes you just want to have fun banging away, and this was clearly not the gun for those times. If only there was something the loaded clip could be put into, to keep the pellets in!

What is plastic printing?

Plastic printing is a system where an electronically described part is built up out of thin layers of extruded plastic. The parts can be modeled using traditional CAD (Computer Aided Design) software, or with more modern but functionally limited software specifically written for 3D printing. Once the part is modeled, the output is handed off to a piece of software called a “slicer”. It does exactly that, reducing the part into layers of predetermined thickness. Have you ever seen a hard boiled egg slicer, a frame with an array of wires? Think of that, but on its side. And the output is the sliced egg, still all stacked so it still looks like a whole egg. The slicer output file is what is sent to the printer.

Sumatra egg
A model egg.

Sumatra sliced model egg
A sliced model egg.

The printer itself is little more than a heated extruder head that is movable in 3D space. It receives a steady supply of room temperature plastic filament from a spool and extrudes it out of a very small nozzle. To put some numbers to it, the filament supply is commonly about 1.75mm in diameter, and in my case the nozzle diameter is 0.4mm. That’s quite a bit of reducing!

The extruded head heats the plastic to its melting temperature (that depends on the plastic type, but it’s usually over 205 degrees celsius or 401 degrees F.), and uses the pressure of the fed plastic to push the melted plastic out the nozzle. It can be printed (deposited?) in layer heights ranging from 0.1mm to 0.4mm on my machine, with a default at 0.2mm. That’s 0.0079-inches!

How does the printer print?

Imagine that the object you’re printing is a pyramid, 5 cm tall (that’s almost 2 inches) , 5 cm on each side, and your slicer program is set to make 0.2mm layers. The base layer the printer will print will be a 5x5x0.2mm square (well, technically, a cube). As the print continues, it lays down the next layer of extruded plastic on top of the first. This square will be a little less than 5×5, and now your part is 0.4mm tall. And so the process goes, laying down layer after layer. This part would take 125 successively smaller layers to print.

Early success: the clip holder

The first problem I set out to address was the clip holder. I had in mind a part where one edge copied the outline of the gun where the clip loads, so the pellets wouldn’t have any spaces to fall out. There would also be an internal track that the clip’s bearings would ride in to keep the clip centered. To keep the clip in the holder, I planned a pair of depressions that were deeper than the track, that the bearings would center in. I enlisted the help of a machinist cousin, and in a couple of hours, we had a model. Once my printer arrived, the real fun began!

Sumatra holder face
The clip is in the printed holder.

Sumatra mated to gun
The holder has been mated to the Sumatra, for loading.

Sumatra mated to gun 2
A second view of the clip holder, and how it mates to the gun, preventing pellets from falling out during loading. Just push the clip through the holder and into the Sumatra’s receiver!

Iteration is what makes this process great!

I started using the first prototype, and quickly realized that it could easily be improved on. Adding a lip that would engage the loading slot of the gun would cut down on having to really be attentive when alining the loader with the loading port. An edit to the model added that lip, and now loading became just a wiggle of the holder to make sure the lip was engaged, and a push on the clip. It’s better already!

Sumatra lip vs no lip
Here is a side-by-side comparison that shows the added lip.

Follow on success: belt and gun mounts for the clip holders

I printed out a few of the loaders and headed out to the field. It was a little like having a different gun! I could pop the empty mag out, get a loaded holder from my pocket, and load up just like I’d wished. And it could be done with the muzzle pointing downward, which was much more natural. But again, by actually using the parts I’d made, the next iteration became obvious. Why keep fishing into my pocket, when I could make a belt holder for the loaders? So I figured out a tray to capture the clip holder, and tinkered with making various types of belt holders. One holder was intended to be carried on the front or side of my hip, and the other for further around my back. Now I could head out with ammo for 36 shots, ready to go!

Sumatra belt holders
The two belt carry designs. The trays are angled on the one intended to be worn on your side, to allow for a comfortable wrist angle. That made a huge difference!

But then came the next question — why reach all the way down to my belt at all, as opposed to keeping the clips on the gun itself? So, I tinkered up and printed couple of refining iterations of gun mounted clip holders. And finally I had what I considered to be a really good product. 18 shots, and my hand never had to move more than a couple of inches from the gun.

Sumatra side holders
Here is the “final” side holder. Final, for now… read more

Artemis PP700S-A PCP pistol: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2

Artemis pistol
Artemis PCP air pistol.

This report covers:

  • Slow regulator
  • Fill
  • The test
  • Sight-in
  • RWS Superdomes
  • JSB Exact RS
  • JSB Hades
  • H&N Baracudas
  • Field Target Trophy
  • JSB Exact Jumbo
  • Observations
  • Summary

Today we take our first look at the accuracy of the Artemis PP700S-A PCP pistol. I shot it using the sights that come on the gun.

Slow regulator

I read Part 2 before starting the test, because I knew the regulator on the pistol took a long time to settle down after a shot. From the comments of some readers who own the gun, my experience is typical and goes away as the gun breaks in.


I also read where I had discovered that the test pistol does not want to be filled to 3,000 psi. It likes a 2800 fill, so both times I filled it that’s where I stopped. And again there was owner agreement.

The test

I shot off a sandbag rest at 10 meters. The pistol was rested directly on the bag, so there was little or no motion. I decided to shoot 5-shot groups that would allow me to test more pellets than if I had shot 10 shots. I tried to wait about two minutes between each shot, which we learned in Part 2 is the amount of time it takes the regulator to fill.


When testing a new airgun I never know where the first shot will hit, so I usually start shooting 10-12 feet from the target. But when the gun being tested has open sights I figure the pellet will be pretty close to on, right out of the box. Wrong! The first pellet hit the target 2.75-inches below the aim point and a little to the left. There is no elevation adjustment. I could adjust the rear sight right and left, but I left it alone for now. And that turned out to be fine because pellets went both right and left.

RWS Superdomes

The first pellet to be tested was the RWS Superdome. Though I aimed at the 6 o’clock on the upper bull, 4 of the five shots hit at the very bottom of the bull below it, and one was even lower and off the target paper altogether. Because of that I had to photograph the targets differently this time.

Five Superdomes went into 0.858-inches at 10 meters. Four shots are sort of together in 0.59-inches, which is better. It was the first shot that hit below the paper.

Artemis Superdome group
Five RWS Superdomes went into 0.858-inches at 10 meters, with 4 shots going into a tighter 0.59-inches.

JSB Exact RS

Next I tried 5 JSB Exact RS pellets. I thought, given the pistol’s lower power, that perhaps lighter pellets were the answer. But I was wrong. This time five went even lower on the target into a group measuring 1.175-inches between centers.

Artemis Exact RS group
Well, it’s clear that JSB Exact RS pellets are not right for this Artemis. Five went into 1.175-inches at 10 meters.

JSB Hades

When I was at the Texas Airgun Show a few weeks ago, a reader gave me a tin of JSB Hades hollowpoint pellets. He told me after testing them he purchased 40 tins immediately. I had already requested a tin and had it on hand for a special test, but after hearing his confidence I knew I had to include them the first chance I got. And this was it.

Artemis Hades
The Hades is a new hollowpoint pellet from JSB.

Five Hades pellets went into 0.716-inches at 10 meters. There are actually two separate groups of three and two pellets, so the potential is for this pellet to stack at this distance! This was the smallest group of the test, which makes it clear why he was so enthusiastic about them!

Artemis Hades group
JSB Hades hollowpoints made the smallest group of the test, measuring 0.716-inches between centers. The hole on the right has three pellets in it, which shows what this pellet really wants to do.

H&N Baracudas

The next pellet I tried was the H&N Baracuda with a 5.50mm head. What a tease it was, because 4 of the 5 went into 0.234-inches, but one of the five opened the group to 0.763-inches. I have a feeling this is another pellet to try when the pistol is scoped.

Artemis Baracuda group
Four Baracuda pellets are in 0.234-inches at 10 meters, but one of the five opened the group to 0.763-inches.

Field Target Trophy

The next pellet I tried was the H&N Field Target Trophy with a 5.53mm head. I have never had much luck with this pellet, though I know many shooters do. You might think that introduces bias into the test, and perhaps it does, but I really did shoot my very best. Five pellets went into 1.443-inches at 10 meters, though four of them are in 0.517-inches. I guess that’s better than it looks.

Artemis Field Target Trophy group
The Artemis put 5 F&N Field Target Trophy pellets into 1.443-inches at 10 meters. That’s the largest group of the test, but 4 of those 5 are in 0.517-inches. read more