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

Making a case for pistols

by Tom Gaylord
Writing as B.B. Pelletier

Writing as B.B. Pelletier

Today’s report is another guest blog from reader Ian McKee who writes as 45 Bravo. Today he tells us how to make custom cases for our airguns.

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

Ian McKee
Writing as 45Bravo

Making a case for pistols. 

This report covers:

Double meaning
Why do you need a box for each gun?
And, you are done!
But wait there is more!
We don’t have to have boring metal or plastic pellet tins

A nice air pistol like this Walther PPK/S deserves a nice case.

Double meaning

Ok, that title can have more than one meaning, so today I will be actually be doing both.  read more

HW 35 Luxus: Part 4

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2
Part 3

HW35 Luxus

This report covers:

  • Disassembly
  • Rekord trigger
  • End cap comes out
  • Mainspring and guide come out
  • Piston is next
  • Assembly
  • The safety
  • Back together
  • What’s next?

Today, we’ll look inside the HW 35 Luxus to see what we find. I’ve thought from the beginning that this is a tuned air rifle, and I’ve given you the clues why. The baseblock is lubricated with some heavy grease that Weihrauch never used, and the safety seems to be defeated.

I also want to find out what material the piston seal is made of. If it’s leather, it needs more frequent lubrication than a synthetic seal would need.


Disassembling most Weihrauch air rifles is easy. Only the R9/HW95 and the new HW50 have those 4 tabs that hold the very thin end cap in the rifle and are a little harder to deal with. But this HW 35 is an old-school Weihrauch that has a threaded end cap.

I loosened three screws, and the barreled action came out of the stock. And I immediately know that my rifle has been tuned. I can see black tar on the mainspring — something only a tuner would ever put there.

Rekord trigger

The Rekord trigger comes out first after driving out the 2 pins that hold it inside the end cap. Once it’s out, there’s more evidence of a tune — there’s moly grease on the sear hook that grabs and holds the piston when the rifle is cocked. The other end of the sear, which is blocked by the trigger, is also coated with moly.

Rekord 1
The Rekord trigger looks normal from the side.

But this Rekord trigger is different than others I’ve seen. The piston hook is made from three thin steel plates sandwiched together — very much in the same way that BSF made their triggers.

Rekord 2
This view of the trigger shows three steel plates sandwiched together to form the piston hook. In later Weihrauchs, this part was made from a single piece of steel.

End cap comes out

Next, the end cap is unscrewed. On some rifles, this cap needs a start. I’ve found that the rounded end of a crescent wrench in the slot where the trigger fits provides a good lever. The rounded edges of the wrench don’t hurt the sharp edges of the trigger slot in the end cap.

You always want to put your barreled action in a mainspring compressor to remove the end cap, because you don’t know how much compression the mainspring is under. On this rifle, there’s an additional 1-1/2 inches of spring movement after the end cap separates, before all tension is off the mainspring. The mainspring compressor allows you to handle the parts without any strain.

Mainspring and guide come out

Once the end cap is off, the mainspring and spring guide can be pulled out of the spring tube. I was wearing gloves because this mainspring is heavily coated inside and out with an extremely tacky black tar. I wish I knew what this stuff is, because it very much resembles the stuff Ivan Hancock used to put on the Mag 80 Laza springs for his special tuning kit. It’s thicker and tackier than any material I’ve been able to find.

When I tugged on the Weihrauch factory spring guide, it didn’t move. I think the mainspring fits the guide very tightly, but that black tar grease is certainly helping. I handled these parts very carefully, because I didn’t want too much of that stuff to rub off. I didn’t have anything as nice to replace it.

mainspring and guide
The mainspring is coated with a special black tar grease inside and out. The factory spring guide fits the spring very tight.

The spring is straight. It looks good to go for the next 10,000 shots at least.

Piston is next

The piston comes out next. It’s connected to the barrel by the cocking link, so the barrel has to come out of the action forks at this time. On a Weihrauch, this is very easy to do. First, remove the pivot bolt nut on the right side of the gun. Then, the pivot bolt can be loosened and taken out. Once it’s out, the barrel slides out of the action fork, and you can unlatch the cocking link from the piston.

pivot bolt
Now, the pivot bolt comes out so the barrel can be separated from the spring tube. Then, the cocking link can be detached from the piston, and the piston can be removed. Notice that the cocking link is two-piece.

When I did this, I noticed that the baseblock and pivot bolt were coated with the same black tar that was on the mainspring. Either this tuner knows something I don’t, or he’s using the black tar like a hammer and sees every part of the airgun as a nail. What I mean is that you don’t use black tar to lubricate metal-to-metal parts, though that’s the original purpose of the product. I use moly on these parts because it lubricates better and lasts longer.

I also note that he used moly on the front and back of the piston, which is exactly correct. So, maybe he knows something I don’t.

The piston seal is leather, which is what I’d hoped. It appears to be in perfect condition and should outlast me if I keep it well-oiled.

The piston is coated with moly front and rear — exactly as it should be. read more

RWS Diana 45: Part 8

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7

RWS Diana 45 air rifle
Diana 45 is a large breakbarrel spring rifle.

This report covers:

  • RWS Superdome pellets
  • Uh-oh!
  • RWS Hobby pellets
  • Air Arms Falcon pellets
  • Time to stop and think
  • H&N Baracuda Match pellets with 4.53mm head
  • Where we are

Today, we’ll look at the performance of the Diana 45 that we tuned recently. Although a new mainspring was installed, it has the same power as the spring that was in the rifle, so no vast power increase was anticipated. If there’s any increase at all, it will probably come from the new breech seal I installed. The old one was flat and hard, so the breech is probably sealing air better now.

The point of this tune was to eliminate as much vibration as we could. The rifle’s owner, Johnny Hill, did not like the buzz that came with every shot, and I told him that most or even all of that could be eliminated by tightening the tolerances inside the powerplant. At my request, he made a larger spring guide, and he buttoned the piston to take out as much vibration as possible.

Our plan worked to an extent because the rifle is now calmer, but some vibration still remains. I’ve never worked on a Diana 45 before, and this may be as good as it gets — or there may be some secrets about this model that I don’t know. This is as good as I’m able to make it shoot. I estimate that 75 percent of the previous vibration has gone away.

Now, let’s look at the velocity. The 3 pellets I tested this rifle with in Part 2 are the RWS Superdome, the RWS Hobby and the Air Arms Falcon. That’s where I’ll begin.

RWS Superdome pellets

First up are the Superdomes. When the rifle was still in factory trim in Part 3, they averaged 735 f.p.s. with an 18 f.p.s. spread. This time I got 870 f.p.s. on the first shot, but then the velocity started dropping off right away. By shot 14, the velocity was down to 803 f.p.s., where it seemed to be leveling off.

A second string of 10 shots produced an average velocity of 800 f.p.s. The high was 811 f.p.s., and the low was 787 f.p.s. That’s a spread of 24 f.p.s. I think the rifle is still breaking in and will shoot somewhat slower after a thousand shots, but it’s definitely faster than it was before the tuneup. However, there was an anomaly in this string.

At the average velocity of the second string, this pellet produces 11.8 foot-pounds of energy. I do think the average will be less after several hundred additional shots have been fired, but it’ll probably still be significantly faster than the 735 f.p.s. average before the tune.


In the middle of the second string, two shots went 509 f.p.s. and 524 f.p.s., respectively. Since the velocity on the very next shot was 804 f.p.s. and never again dropped lower than 787 f.p.s., I eliminated those 2 shots from the string and fired 2 more shots to replace them. But they did give me cause to wonder what was happening.

RWS Hobby pellets

The second pellet I tried was the 7-grain RWS Hobby. Before the tune, Hobbys were averaging 793 f.p.s. with a 28 f.p.s. velocity spread. Now they averaged 890 f.p.s. with a spread of 20 f.p.s. spread from 881 to 901 f.p.s. At the average velocity, Hobbys produce 14.6 foot-pounds of energy at the muzzle.

But there was another single anomalous slow shot in the string that went only 603 f.p.s. I excluded it from the string like before, but now I was really starting to wonder what was happening! I didn’t think it was the chronograph’s fault, though that is something I will have to look into.

Before I move on I would like to take a moment to reflect on what this rifle is doing. The Diana 45 is one of the original Four Horsemen of the 1970s. They were the first 4 to break the 800 f.p.s.”barrier,” ushering in the era of magnum spring-piston air rifles. Back then, the Diana 45 was advertised as getting just over 800 f.p.s. and could possibly be tuned to get up to 860 f.p.s. So, the fact that this one has just averaged 890 f.p.s. makes me feel a little proud. It probably won’t last, but it’s nice to know I can do it. And, yes, I know they probably didn’t have Hobby pellets to use for testing in the 1970s, but we don’t have to go there — do we?

Air Arms Falcon pellets

Next up was the Air Arms Falcon pellet. The first shot went out at 816 f.p.s.; and after that, none of the next 6 shots went faster than 448 f.p.s. I didn’t record a string because I felt this wasn’t the right pellet for this rifle as it is now tuned.

Time to stop and think

These slow shots were beginning to concern me. Especially when I shots 6 Falcons in a row in the 400s. Was the rifle somehow failing? It felt the same every time it shot, but the numbers were telling a different story.

I thought the Falcon pellets that loaded into the breech very easily weren’t resisting the piston with enough force. Perhaps, the pellets were moving before the piston slammed home and not allowing the air pressure to build up. The lighter Hobby didn’t seem to have the same problem, except just one time. And the Hobby fit the breech much tighter.

So I decided to try a pellet that I knew would give a lot of resistance. The H&N Baracuda Match pellet with a 4.53mm head is both fat and heavy. That would surely give the piston all the resistance required.

H&N Baracuda Match pellets with 4.53mm head

Ten shots with H&N Baracuda Match pellets with 4.53mm heads gave me an average 676 f.p.s from the Diana with a 46 f.p.s. spread from 658 to 704 f.p.s. There wasn’t a single slow shot in this string. At the average velocity, this 10.65-grain pellet produced 10.81 foot-pounds of energy at the muzzle. By the way, the average for this pellet (676 f.p.s.) is very close to the “magic” velocity of 671 f.p.s., which is the speed at which the weight of the pellet in grains equals the muzzle energy in foot pounds.

Where we are

We now have a tuned rifle that’s ready for one last accuracy test. That will be done at 25 yards with a scoped gun. Unless something odd happens, I’ll pronounce the rifle finished and return it to its owner with a couple recommended pellets.

For kicks, I might chronograph the accurate pellets after the accuracy test — just to see if I still get a slow shot now and then. If I still do, and the pellets that do it are accurate at 25 yards, I need to look at the chronograph. Velocities can’t drop by 200 f.p.s. and not affect where the pellets land at 25 yards.

I haven’t told you yet, but this test was the first one conducted using the new chronograph Pyramyd Air sent to replace the Alpha model I shot up last week with the Benjamin Bulldog. This one is an Alpha Master that has a removable display and controller with an 18-foot cord, so now I can set the chronograph out on the range and operate it from safety. I’ll report on this chronograph after I gain some experience using it.

RWS Diana 45: Part 7

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2
Part 3
Part 4
Part 5
Part 6

RWS Diana 45 air rifle
Diana 45 is a large breakbarrel spring rifle.

This report covers:

• Barrel must go on
• Piston into the tube
• Piston liner and cocking shoe go in
• Install the barrel
• Install the trigger
• Install the barreled action in the stock
• Quick function test

Barrel must go on
I’ll pick up where I left off in the last report. To assemble the parts, the barrel has to go on the spring tube. During disassembly, I’d noticed during that the breech seal was flattened and hard, so it was replaced before anything else was done. It’s just an o-ring with a steel spacer underneath, so the old one was pried out and a new one was pressed into the groove.

Diana 45 breech seal
The old breech seal is out and the new one is in.

Now, the barrel goes onto the spring tube. This is necessary because I’ll put the barreled action back into the mainspring compressor to assemble the gun, and the barrel needs to be on for that. The cocking link that’s connected to the baseblock on the barrel must be connected to the sliding piston shoe at this time, or the parts cannot be assembled. So, a number of things must happen in sequence.

Piston into the tube
First, the piston goes into the spring tube. The buttons hung up on some cutouts in the spring tube and had to be forced past them, which sliced off a portion of one button. Fortunately, no great damage was done. Those cutouts are the reason that I don’t think a circular piston ring of Delrin will work in this rifle.

Diana 45 inside spring tube
The inside of the spring tube has several cutouts that caused problems when installing the piston. Once the buttons were past them, the piston slid smoothly and was still very tight in the tube.

Piston liner and cocking shoe go in
Once the piston is in, the piston liner and cocking shoe go in. Now, you’ll see why I lubed the liner.

Diana 45 cocking shoe
Remember this part? It’s smaller than the cocking slot in the piston, so the black piston liner is what holds it in place. During assembly the shoe goes into the piston. Then, it’s raised to this level, and the piston liner is slid underneath it. read more

RWS Diana 45: Part 6

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2
Part 3
Part 4
Part 5

RWS Diana 45 air rifleDiana 45 is a large breakbarrel spring rifle.

This report covers:

• Piston head swaged
• Eliminate sloppy tolerances
• Buttons
• Tighter spring guide
• Remove all burrs
• Clean the spring tube
• Lube the spring tube
• Lube the piston, piston liner and mainspring
• Lube the leather piston seal
• Leave the trigger alone

Today, I’ll show you all the things that have been done to the Diana 45 parts; and I’ll clean, lubricate and assemble the rifle. This will be a long report, so I am breaking it into two parts — today and tomorrow.

Piston head swaged
Before we get to the job though, I was asked by one reader to show how the piston head is attached to the piston body. If you want to replace the leather piston seal, the piston head has to be removed — and that isn’t going to be easy, because it is mechanically swaged onto the piston body.

swaged piston head
Looking through the cocking slot, we see the piston head has a groove cut around its base (arrow). The piston body is swaged into this groove by several mechanical punch marks around the end of the piston body. This is a fast way to assemble the head to the body, but the piston head will be difficult to remove. read more

Things you can do to make your new airgun better: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2

This report covers:

• Shoot it!
• Test it!
• Clean it — maybe
• Oil it — maybe
• Keep your hands off!

Today, I’m going to look at precharged pneumatics (PCP). Maybe you thought these came ready to go right from the factory, and in many ways they do; but even with this powerplant, there are always things you can do to make the guns shoot better.

Shoot it!
The first thing is something most people are going to do anyway — I just want to make you aware of how it affects your gun. Shoot it! Don’t take it apart to see how it works and if you can “correct” all the flaws the “stupid” factory left in the gun when they made it. Don’t send it off to be tuned. Just shoot the thing, and it will get better.

Back when Falcon airguns were being made in the UK, they used to come from the box at one velocity — let’s say it was 890 f.p.s. with a .177-caliber H&N Baracuda Match. A thousand pellets later, the same rifle might be getting 960 f.p.s. from the same pellet. Falcons always increased in velocity as they broke in. That’s something my friend Mac taught me. He owned 6 Falcon air rifles, and each one of them got faster the more it was shot.

I started watching, and lo and behold my brand new Daystate Huntsman did the same thing. It started out at 875 f.p.s. with the same pellet and was up to 930 when I started competing in field target with the rifle, about 500 pellets later. Of course, to notice such things, you have to have a chronograph and use it.

Test it!
The second thing you can do for your PCP follows from the first. Test your PCP to establish the optimum fill pressure. Don’t read the manual and then slavishly fill to exactly 3,000 psi on the dial of your fill gauge just because that’s what it says in the book. It’s a good bet that your gauge is off by some amount, anyway, so use that chronograph to find out what works best with your particular airgun and your particular gauge. Use the owner’s manual as your starting point.

My Daystate came with instructions to fill to 2,600 psi. But that didn’t agree with the fill gauge on my scuba tank — and THAT did not agree with the gauge on my hand pump that I ultimately used exclusively in competition. I discovered that if I filled my rifle to 2450 psi, as indicated by the gauge on my hand pump, the rifle gave me 24 shots that didn’t vary by more than 10 f.p.s. That information didn’t come from any manual — it came from testing the rifle over a chronograph with the pellet I intended using. Once I discovered that, I made an indelible mark on the cover of the gauge of my hand pump — a mark that is still there today, even though the rifle’s long gone.

Clean it — maybe
This trick I learned from the late Rodney Boyce, who sold me both my Daystates. He told me that PCPs shoot with dry bores, and they sometimes get lead in the rifling that affects accuracy. He said that, whenever accuracy falls off, you need to clean the bore. Then Ben Taylor — the Ben of Theoben — told me exactly how to clean an airgun barrel. Use a brass bore brush (steel barrels only) that’s loaded with JB Non-Embedding Bore Cleaning Compound and run it through the bore both ways 20 times. Clean out the residue, and the bore will be clean. I’ve been cleaning airgun barrels that way ever since, and it works.

And while I’m on the subject — don’t get hung up on the fact that Brownells calls their brush a bronze brush and I said to use brass. Brass or bronze — they all work the same. When the exact material really matters, such as when I say to use Silicone Chamber Oil, I’ll tell you that I don’t want you to use the silicone oil that comes in spray cans for oiling door hinges. And, I’ll tell you why.

Before I leave this subject, I have to say one more thing. LEARN ABOUT LEAD AND LEAD ALLOYS!!!! For over 50 years, I’ve had to know about the subtle differences between pure lead and certain lead alloys because I cast my own bullets. It really matters. If you use lead that’s been hardened with antimony, I guarantee that your bullets will leave lead deposits in the bore of your gun! I first discovered this in about 1968 while shooting a .45 Colt Single Action. But over the years, I have seen only a few gun writers who know that this happens or why.

Antimony is used to harden the lead alloy when you want to shoot a bullet very fast. Soft lead alloys will not withstand the rotational torque of the bullet when shot fast. In short, they’ll strip the rifling (they will not allow the rifling to grab and guide them) and will be inaccurate.

This leading happens more as the velocity increases, so until you top about 750 f.p.s. with pellets you won’t notice it. But when you shoot Crosman Premier pellets in an airgun at 900 f.p.s., they’ll lead the bore! It’s gradual at first, but it does accelerate as the lead builds up. Those using Premiers should clean their barrels when the accuracy drops off. But don’t be a slave to cleaning!

I know an airgunner who claims he cleans his barrel with JB Paste every 200 shots! Folks, that’s not cleanliness — that’s insanity! He’s being anal. This fellow will clean his barrel so often that a time will come when it will have to be cleaned all the time, because of the mechanical damage he has done from the rod impacting the rifling. Only clean your barrel when the accuracy falls off. And, if Premier pellets are the most accurate pellets in your airgun, by all means use them. I do!

Oil it — maybe
I do oil my PCP airguns. I use silicone chamber oil and put it in through the air intake port — the same way we put Crosman Pellgunoil into a CO2 gun. I know what this oil does for a PCP powerplant, and I do this as a matter of course. You don’t have to do it, and I am not advising you to. But if your PCP has a slow leak (loses pressure after a week), then some silicone chamber oil might fix it.

And, no — I didn’t say to use automatic transmission fluid or whale snot or Jake’s Sure-Fire Fix-it Oil. I said silicone chamber oil — period!

Keep your hands off!
The best advice I can give is going to roll right off the backs of those who need it the most. Leave your airgun alone! Just shoot it, and then shoot it some more. If there are adjustments (trigger, power, etc) avoid making them until you’ve shot your gun enough to know when an adjustment makes a real difference. I read about guys getting brand-new PCPs and tearing into them like they’ve been working at the factory for the past 10 years. They get knee-deep in the innards, and only then does it occur to them that they don’t know what they’re doing.

There’s a delicate balance between the striker weight, the power of the striker spring, the length of the striker travel, the diameter of the valve port, the shape of the valve head and seat, and the strength of the valve return spring. Is that complex enough for you? Your airgun has been designed to work best with the combination of these variables that’s in the gun when it leaves the factory. Changing any variable affects the others and may take the performance of your airgun outside the envelope in which it was designed to work.

When I worked at AirForce Airguns (2003-2005), I got to see the damage people will do to airguns. One case was particularly interesting, because the man who had brought us his nearly new and hopelessly broken Condor was posting on forums how to soup-up Condors at the same time he was asking us to fix the rifle he had destroyed. His “heavy” striker weight hammered apart the valve in his gun. It also ruined the screw hole in the frame that holds the threaded boss that the tank screws into. We fixed that as best we could, but he really ruined the rifle’s frame, which is the heart of the whole gun. Be wary of people who are self-proclaimed experts.