Design an Airgun contest, Part 2

Tom Gaylord
Writing as B.B. Pelletier

Part 1

This report covers:

  • Several entries
  • Norica bullpup
  • Nerf gun
  • Two great entries!
  • Maximus Blowhardus
  • Learned something
  • Spaghetti blowgun
  • Catapult gun
  • Without further ado, My plinker:
  • Some of the features I incorporated:
  • Penny shooter
  • The simplest entrant
  • Stonebow
  • Wow!
  • A hard job
  • Summary

Today we learn who is the winner of the Design an Airgun contest. It began on September 10 and was supposed to end at the end of the month, but several readers asked me to extend the closing, so I did. The contest ended last Friday, October 16.

Several entries

There were several entries. Some were blue sky dreams and nothing was built. I didn’t take them seriously. But some folks submitted more than one entry and they built all of theirs. I considered everything on the basis of the contest rules, which were:

1. I’m guessing it will be a BB gun, but it doesn’t have to be.
2. I’m guessing it will be a smoothbore, but again, it doesn’t have to be.
3. When I say build an airgun, it doesn’t have to work with compressed air.
4. It can be any kind of powerplant — so long as it doesn’t use an explosion to launch the missile.
5. The winner would be the niftiest design that the most people could build.
read more

AirForce Edge 10-meter rifle: Part 5

by Tom Gaylord
Writing as B.B. Pelletier

AirForce Edge
AirForce Edge.

Part 1
Part 2
Part 3
Part 4

This report covers:

  • Behind the curtain
  • Field measurements
  • Test 
  • Low velocity
  • Different valve
  • H&N Finale Match Heavy
  • RWS Meisterkugeln Rifle
  • Shot count
  • Short on air?
  • Hammer spring
  • What else have I learned?
  • Summary

Today is unusual because I’m doing a back-to-back report on the AirForce Edge. I don’t normally do that, but I discovered some very interesting things that will probably help a lot of you with precharged pneumatic airguns of any kind. Also, I got into this project and just couldn’t stop until it was finished. I know you know what that’s like. Let’s get to it.

Behind the curtain

There were several things I did not tell you in Part 4 last Friday. I did them then, but the results were outside the scope of the report, so I held off. Today they will make a lot more sense. 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

RWS Diana 45: Part 5

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2
Part 3
Part 4

Diana 45
Diana 45 is a large breakbarrel spring rifle.

This report covers:

• Remove the barrel
• Barrel off!
• Remove the piston
• Disassembly is complete
• One last look

We have a lot to cover today, so let’s get right to it. We left the Diana 45 with the mainspring out of the gun at the end of yesterday’s report. The only thing left in the disassembly is to remove the piston. Do not disassemble a gun if you’re not 100% certain you can put it back together again in safe working condition!

Remove the barrel
The piston will not come out of the gun until the cocking link that connects it to the underside of the barrel (for cocking) is removed. To do that, you must first separate the barrel from the spring tube. That step is easy on some breakbarrels, but not so easy with this 45. On most breakbarrels, you remove the pivot bolt from the action forks and the barrel separates from the spring tube. The Diana 45 has another step; and unless you follow it, the barrel will never come off the gun.

I unscrewed the pivot bolt with a Phillips screwdriver. The nut on the other side stayed in place and allowed the bolt to back out. With the bolt out, I could see the star lock washers that are on either side of the pivot bolt hole.

Diana 45 pivot bolt out
The pivot bolt and nut are out, and you can see the star lockwasher still in the hole. With this bolt removed, the barrels on most guns will come out of the action forks (at the end of the spring tube), but not the Diana 45 barrel. There’s still one more thing to do.

The barrel still won’t separate from the action fork. Something is holding it in place. When you remove the star washer, you see a bushing that acts as a bearing for the pivot joint. The pivot bolt passes through this bushing, and it’s the bushing that takes the full load when the gun is cocked. This bushing drives out of the baseblock with little resistance.

Diana 45 pivot bushing
Under the star washer, we find the barrel pivot bushing. This also has to come out before the barrel comes out of the action fork.

After I drove the bushing out of the baseblock, all the parts that hold the barrel in the spring tube action forks are out of the gun. It’s quite a list. They include the pivot bolt, the pivot bolt nut, two star washers and the pivot bushing that acts as a bearing when the rifle is cocked.

Diana 45 pivot parts
All the parts that hold the barrel to the action. The pivot bushing that acts as a bearing is the part that was unexpected. read more