Oil talk — and no action!

by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • WD40
  • WD40 as penetrating oil?
  • Not for clocks!
  • Air Rifle Headquarters
  • Light oils
  • Use for airguns
  • Special purpose weapons-grade oil
  • Household oil
  • Special purpose oils
  • Ballistol
  • Silicone lubricating oils
  • Silicone chamber oil
  • Crosman Pellgunoil
  • Summary

Okay — today is a report several of you readers asked for — some common sense talk about which oils to use on airguns, and where. It has to be common sense because I am not a petroleum engineer. I’m just a guy like you who has used a lot of oils over my 73+ years. And I will start with the one that started the discussion.


WD40 was created in 1953 by a small aerospace engineering firm called Rocket Chemical Company. They were looking for a formula to displace water for the aerospace industry. On their 40th attempt they succeeded and called the product WD40.

Aerospace contractor Convair first used WD40 to protect the outer skin of the Atlas missile from rust and corrosion. It worked so well that some employees sneaked some cans out of the plant to use at home. A few years later, Rocket Chemical founder Norm Larsen put WD40 into aerosol cans, to see if the public would find uses for it. It hit the shelves in San Diego, Rocket Chemical’s home, in 1958.

My own introduction to the stuff came around 1965, when my stepfather showed me how to dry the points of a car that had stopped running after splashing through a high puddle. But a few years later I was spraying all the firearms on my tables at gun shows because the stuff smells so nice. The purpose was to prevent rust, which the product does, and when you wipe it off, all the fingerprints and spots come off the blued finish.

My use for that purpose came to a screeching halt in December of 1977 when I returned from Germany and retrieved the guns that I had left with my parents. I had sprayed all of them with WD-40 when I left them there in 1974 and they were now covered with a yellow varnish that was so hard I had to pound on the bolt of my bolt-action rifle  with a plastic hammer to get the action open! It took me months of cleaning to get that varnish off all the guns and WD40 was what I used. The solvent vehicle is naphtha (its hidden as a petroleum distillate in the US product contents but specifically called out in Australia) and it works wonders to dissolve the dried product.

WD40 as penetrating oil?

I see on some of the British car shows on TV that WD40 is used as a penetrating oil, and I can’t deny that it does work that way. I never used it that way myself, but that was probably more because I was a gun guy rather than a gearhead.

I no longer use it on guns like I did in the 1970s, but like many households there is a can or two around. Yes, it will quiet a squeaky door hinge, but less than a year later the squeak will be back. A shot of silicone lubricating oil lasts for a decade easily.

Not for clocks!

I attended an horological (clock and watch repairman, as well as those just interested in the measurement of time) club’s meetings for about 6 months in the early 1990s — thinking that I might take up horology as a hobby. That was until I discovered that the tools a horologist needs costs thousands to acquire and the knowledge takes years to learn! I was about 44 years old and was the youngest guy at the meetings by several decades. 

One meeting we had was all about oils for clocks and watches. When WD40 was mentioned everybody went into low earth orbit and they all had horror stories that were pretty much the same as my gun story from years before.

I have no recommended applications of WD40 for airguns. If you do use it, remember what I said about it drying and leaving a varnish residue.

Air Rifle Headquarters

Yes, Air Rifle Headquarters did recommend WD40 for displacing water and preventing rust, which it was formulated to do. But they also called it a multi-purpose lubricant, which is was not and still is not today. ARH also recommended a lubricant called Dri Slide that was moly particles suspended in a volatile petroleum distillate (naphtha) base. I used Dri Slide a couple times until realizing they every piece of uncoated steel I used it on developed rust within a week! Dri Slide is still being made and sold today and no doubt it has applications but I’m warning you not to put it on steel parts that are in the white (uncoated). You must remember, Air Rifle Headquarters wrote their catalogs in the 1970s, when less was known about many things.

Light oils

Okay — got that out of the way. Now let’s talk about some oils you can use on airguns and why you would choose to do so. I’ll begin with light oils. Like I said, I’m no petroleum engineer, so I’m just going to talk about this like I would if you were standing right here beside me. There are lots of light oils, and by “light” what I mean is oils with low viscosity. I suppose penetrating oil qualifies, but I would like to address it separately. What I’m talking about now are light lubricating oils.

I’ll start with your wife’s sewing machine. If it’s a good one and if she knows how to care for it, she has a bottle of very lightweight oil. It’s white mineral oil. Every so often, based on the amount of use or the time that has lapsed, she oils several places on the machine and then runs the motor wide open to spread the oil. It doesn’t collect on the parts and gears like WD40 does.

Another light oil is clock oil. Most of it these days is synthetic and is very low in viscosity to penetrate between the jeweled bearings or just the brass plates and the steel pinions that turn in them. This oil comes in grades that are formulated specifically for wall clocks and grandfather/grandmother clocks.

Skateboard oil is yet another light oil for the bearings of skateboards and roller blades. It is thicker than clock oil and sewing machine oil. It has superior wearing capability despite the lower viscosity.

Use for airguns

Use light oil sparingly for an airgun. Most of it won’t stand up to the heavy wear it needs to, but on things like triggers, beartraps, some detents and things like that, it is okay. If the detent will see heavy use, like a breech locking detent, I wouldn’t use light oil.

Special purpose weapons-grade oil

These oils didn’t really exist when I was a kid. I think LSA (lubricant, small arms) was my first encounter. And by the way, this stuff is also called lubricant, semifluid, automatic (weapons) and lubricating oil, semifluid. When I was in the Army we all carried a small plastic bottle of it for our M16s, and, if used correctly and in the right amounts (which is more than most soldiers think), it works well.

Other weapons-grade lubricants are mostly a mystery to me, but I did use EWG (Extreme Weapons Grease) in place of Tune in an Tube to quiet the mainspring and cocking link of a Diana model 50 spring-piston air rifle. It worked great and the spring was quiet. This report isn’t about greases, so that’s all I will say, except to note that if an oil says it is specially formulated for weapons, it probably is and should be worth a try. I would use special purpose weapons-grade oils according to the directions on their label.

Household oil

When I write “household oil” for this blog I’m thinking of 3-IN-ONE oil. But it doesn’t have to be just that. I’m sure there are hundreds of household (general purpose) oils around the world that are all pretty close or identical. By sheer coincidence, WD40 purchased 3-IN-ONE oil in 1995, so there you go!

For the past 50 years I have used a can of PL-S Lube Oil, General Purpose as my household oil. As far as I’m concerned it’s the same as 3-IN-ONE, though I’m sure there are experts who know different. But I use it for the same purposes and yes, I also own a can of 3-IN-ONE.

I probably got this one when I was in the Army, or I bought it at a gun show. I use it for all general lubrication, and on airguns that includes lubing the cocking linkage and the pivot bearings (in the action forks of a springer), and any general purpose application there might be. I use it when I need to lubricate without disassembly. It’s a little too viscous for use on triggers that are more complex than the direct-sear types that you find on American multi-pumps. For them I recommend light oil or special purpose greases such as moly paste.

Army oil
I have used this can of general purpose oil for the past half-century.

Use household oil on airguns in the same way you would use it on other things around your house. Just remember, a PCP trigger mechanism is far more complex and not as robust as a door hinge, so keep the household oil use to high-stress parts.

Special purpose oils

Most of you will not have heard of assembly oil, but those who work on complex  mechanisms might have. Like assembly grease only lighter, assembly oil is tacky — to hold those bothersome little parts in place as they are put together. Two good uses on airguns are those teeny tiny ball bearings and super-light coiled springs. After assembly you don’t want heavier grease to impair their function, so assembly oil could do the trick.

assembly oil
This bottle of assembly oil from Dennis Quackenbush has lasted me more than a decade.

Now, what about penetrating oil? Well, WD40 may work well, but I have found that oils that are blended specifically for penetrating work the best. I use Kroil because when I did an internet search it was the product that kept coming up. It’s not the only brand — I used Liquid Wrench for many years. And lots of people swear by PB Blaster. 

Kroil is one of several penetrating oils.

Use penetrating oil as intended. In other words, use it to free stuck fasteners. It’s not a lubricant, strictly speaking, except in a very narrow and limited way. If you need a thin oil, use either one of the light oils I mentioned, or perhaps a weapons-grade lubricant that is also light.

I mentioned oiling the mainspring of the Winchester 422 in Part 2 of that report and I told you I used Snake Oil. Snake Oil is the sort of special purpose oil I’m now referring to. I used it because the 422/Diana 22 is a very low-powered pellet rifle and I didn’t want to hamper its performance in any way. But the mainspring, spring guide and piston were all dry and I wanted to get something on them just to keep them from galling. When steel rides against steel without lubrication it wears the parts away. That’s galling. Any oil in that case is better than nothing.


Ballistol is probably close to a special-purpose weapons-grade oil but it is used almost universally. Besides being good for lubrication it is a superior rust preventive. Many armies around the world use it for their fully automatic weapons. However, where WD40 smells nice, Ballistol smells like a fish market!

Silicone lubricating oils

Now comes a question that people have asked me for many years. Can they use silicone lubricating oils on their airguns? They obviously have a can of the stuff that they use on door hinges and will it be okay on their airguns? Well some will and some won’t. Silicone lubricant is a class of lubricants that spans too wide a spectrum for me to make specific statements. I have a couple cans of it, too and I use it mostly on the many hinge joints of my segmented garage door. For that purpose it works great and it lasts a long time. On airguns, though, I would like to see something more specific and something with a higher viscosity.

Silicone chamber oil

And this is where we get into a lot of trouble with silicone lubricants. Silicone chamber oil has almost no viscosity and will not protect metal parts from galling. But it does have two redeeming features. It seals synthetic piston seals well and it has a high temperature flashpoint. In other words, it doesn’t burst into flame or explode easily. It’s ideal for lubricating spring-piston airguns that have synthetic piston seals. And that’s about all it’s good for on airguns. Use petroleum-based oils on all leather seals exceopt those that are pushing the boundaries of performance, such as the Diana 45.

Oh, some companies recommend silicone chamber oil on the tips of new CO2 cartridges, but only because they don’t have another product to recommend, and they sure aren’t going to recommend a product made by their competitor. Which brings me to today’s final oil.

Crosman Pellgunoil

Crosman Pellgunoil is a blend of non-detergent motor oil and an o-ring preservative. Its number one use is for sealing each new CO2 cartridge before it is pierced, so the oil gets blown into and around the inside of a CO2 gun powerplant to get on all the internal seals. I can’t recommend it highly enough, because it preserves CO2 guns for a very long time.

I use the oil Dennis Quackenbush formulates that’s equivalent to Crosman Pellgunoil.

I keep a bottle of Pellgunoil out all the time. I use it for CO2 cartridges and also for the linkage pivots on multi-pump linkages, as well as on their pump cup heads. Besides the bottle I have a pint of the same stuff in reserve what I hope is a lifetime supply.


Well, that’s my report on lubricating oils and their uses on airguns. As you can see I didn’t tell you specifically which oil to use on the inner cocking link of a Diana 48 sidelever. That’s for you to decide. But, after reading my report, I hope you won’t use silicone chamber oil, Dri Slide or WD40. Household oil would be okay and there might be a special-purpose weapons-grade oil that would be even better.

Crosman 2240 conversion to air: Part 4

by Tom Gaylord, The Godfather of Airguns™
Writing as B.B. Pelletier

Crosman 2240 conversion to air: Part 3
Crosman 2240 conversion to air: Part 2
Crosman 2240 conversion to air: Part 1
R.A.I. Adjustable AR Adapter for Crosman 2240 pistols: Part 2
R.A.I. Adjustable AR Adapter for Crosman 2240 pistols: Part 1

WARNING: This conversion changes the operation of the pistol to use air at up to three times the pressure it was designed for. The parts that are installed are strong, but there are other parts in the gun that aren’t changed and could fail when subjected to the higher pressures. Pyramyd Air advises against making such a conversion. This report is for information, only.

Crosman 2240 air conversion long barrel
The conversion with the Tech Force TF90 dot sight and adjustable stock attached.

This report covers:

• Sight-in at 12 feet
• Back to 25 yards
• End of the test
• Ft. Worth airgun show update
• Boot Campaign

Today, we’ll look at the accuracy of the 2240 on air at 25 yards. I’ve installed a 14.50-inch Crosman barrel on the gun, which boosted the velocity, as we saw last time. It also may have boosted the accuracy. Let’s find out.

The UTG Pro 6-Position Adjustable Stock has been remounted using the R.A.I. adapter. So, this is now a handy carbine.

I’m filling the pistol to 2250 psi, because I learned that was necessary when using the factory valve and a heavier striker spring. I get exactly 10 good shots per fill, which works well with my 10-shot groups.

For a sight, I installed the Tech Force TF90 dot sight that was used to test the Hakim rifle at 25 yards. We saw in that report how well this sight works, so it should work just as well on this carbine-sized gun I’ve assembled.

I sighted-in with 5 shots at 12 feet, and the gun was ready to shoot at 25 yards. I’ll show the sight-in target and explain it, so you can understand how this close sight-in works.

Sight-in at 12 feet
I sight-in at 12 feet because it’s safer. I know I’ll be on paper that close to the target, and I also know where the pellet needs to strike to be on at 20 yards. I used to sight-in all the rifles we sold at AirForce Airguns this way and was always on-target when I backed up to 23 yards. To learn more about this method, read this article.

What I’m looking for is the pellet landing in line (left and right) with the center of the bull, but as far below the center as the center of the sight is above the center of the bore. In other words, if you were to walk up to the target until the muzzle was touching the paper and center the dot (in this case) on the bull, where would the pellet strike the paper?

When you’re 10-12 feet back, the impact point doesn’t change much from that. But when you back up to 20 yards (20-30 yards, actually) the pellet rises up on the paper and ends up close to the aim point. It isn’t exact, but it’s the fastest way that I know to sight-in a pellet rifle.

My sight-in pellets were hitting the target a bit high, but not too high. Once they were centered, I left the sight where it was set and just backed up. I sighted-in with Crosman Premiers.

Crosman 2240 air conversion long barrel sight in
The first 3 pellets hit to the left of center. I adjusted the sight, and shot 4 hit to the right of center. I adjusted back to the left, and shot 5 was close to center. These are hitting too high at 12 feet, but I’ll use the setting as it is.

Back to 25 yards
The first group was fired with 14.3-grain Crosman Premier pellets. The first 3 pellets hit high and right of center. I don’t know how the rest of them hit, but you can see this is a fairly well-centered group of 10 shots. It measures 0.918 inches between centers, which isn’t too bad for a small gun like this at 25 yards. Remember — I’m shooting 10 shots instead of only 5.

Crosman 2240 air conversion long barrel Premier target
Ten pellets made this 0.918-inch group at 25 yards. This is pretty good!

Again, I must comment how nice and clear the TF90 sight is. It really holds a tight group — even though the target appears very small. That makes it a confidence-builder.

Next, I tried the JSB Exact Jumbo RS pellet. These often do well in lower-powered airguns. Remarkably, they went to the same point of impact as the Premiers. That means I don’t have to change the sight settings when using either pellet. This time, 10 RS pellets made a 0.763-inch group! That was very good, I thought. Especially given that I was using a dot sight!

Crosman 2240 air conversion long barrel JSB RS target
Ten JSB Exact RS pellets went into 0.763 inches at 25 yards. This is very good!

End of the test
I’d planned on trying Beeman Devastator pellets next; but when I filled the gun, I noticed a leak at the joint of the HiPAC tank and the pistol’s tube. It was a fast leak and obviously the o-ring wasn’t doing its job. I tried oiling the gun with silicone chamber oil and refilling it, but the leak didn’t stop. So the test was over. I have to find out the problem and fix it if I can.

I do note that the pistol leaked down to 1750 psi and stopped. When I refilled it, the leak was much slower, so the oil may have done something. I think the o-ring and groove need to be cleaned and the tank installed again. But we’ll see.

At any rate, today’s test shows promising accuracy. It may not have been complete, but I’ll return to test the gun again at 25 yards. I plan to mount the TF90 on the Crosman 1077 next, so it may be a while before I get back to the 2240.

Ft. Worth airgun show update
The hotel is filling up fast for the show. Don’t forget to come to the reception at the hotel even if you aren’t staying there. It will be 7 p.m. to 8:30 p.m. Friday evening. Nothing fancy — just a chance to meet and talk about airguns before we set up Saturday morning.

I’ll be taking a caravan of people out to the range Friday afternoon from the hotel at 4 p.m. The range will be open earlier for people who want to get out there by themselves, but please tell me you are going, because this range is private. They need to know you’re coming or the gate will be locked.

We plan to start the door prize and raffle drawings very early after the show opens, and they’ll be held periodically throughout the day. Get there early and buy your raffle tickets for a chance to win a Walther LGV Competition Ultra, an AirForce Airguns CondorSS or a Hatsan AT44-10 Long QE! Since this show will probably not top a thousand attendees, you’ll have a real chance to win one of these fabulous rifles. And everyone who pays admission gets a chance to win an Air Venturi Bronco and a Benjamin Trail NP2 door prize!

Boot Campaign
Another group coming to the show is the Boot Campaign — a Texas-based nonprofit organization dedicated to the military (past and present) and their families — cultivating awareness, promoting patriotism and providing assistance.

Also, American Airgunner TV host Rossi Morreale will be attending the show, as he’s interviewing the ladies from the Boot Campaign.

I’ll have more news about the show as it develops.

WARNING: This conversion changes the operation of the pistol to use air at up to three times the pressure it was designed for. The parts that are installed are strong, but there are other parts in the gun that aren’t changed and could fail when subjected to the higher pressures. Pyramyd Air advises against making such a conversion. This report is for information, only.

Crosman 2240 conversion to air: Part 3

by Tom Gaylord, a.k.a. B.B. Pelletier

Crosman 2240 conversion to air: Part 1
Crosman 2240 conversion to air: Part 2
R.A.I. Adjustable AR Adapter for Crosman 2240 pistols: Part 1
R.A.I. Adjustable AR Adapter for Crosman 2240 pistols: Part 2

WARNING: This conversion changes the operation of the pistol to use air at up to three times the pressure it was designed for. The parts that are installed are strong, but there are other parts in the gun that aren’t changed and could fail when subjected to the higher pressures. Pyramyd Air advises against making such a conversion. This report is for information, only.

Crosman 2240 air conversion long barrel
The steel breech and longer barrel increase the 2240’s length dramatically.

This report covers:

• Installation of a steel breech and longer barrel
• Easy steps
• First velocity test
• Crosman Premier pellets
• RWS Hobby pellets
• RWS Superdome pellets
• What have we learned?
• Replace the striker spring with a heavier spring
• Crosman Premier pellets
• RWS Hobby pellets
• RWS Superdome pellets
• Evaluation to this point

This is the third look at converting a Crosman 2240 CO2 pistol to run on high-pressure air. In the last report, we saw how the conversion works with the factory barrel and factory striker spring. Today I will install a longer barrel with a steel breech and see what that does. Then I will add a stronger striker spring and see what that does.

Installation of a steel breech and longer barrel
Installing a Crosman steel breech and a Crosman 14.50-inch barrel on the 2240 pistol took all of 10 minutes. Four screws were removed, and both the plastic breech and barrel came off. After the detailed disassembly you saw in Part 1 of this report, this modification was a walk in the park.

Easy steps
The new breech was made by Crosman and sold by Pyramyd Air for $38, plus shipping. The barrel was also made by Crosman, and I bought it off eBay for $37 plus shipping. Together, these two parts have added about $85 to the cost of the gun, on top of the $65 for the air conversion that was given to me by Rick Eutsler. That’s an additional $150 I’ve put into this gun. And I’m not counting the adjustable stock and adapter that turns this pistol into a carbine. I’m not complaining about the cost, but don’t let anyone say this is a cheaper route than buying a Benjamin Discovery outright. What you get with this conversion is the time you need to make the investment. You can do this in easy steps.

First velocity test
I left the factory striker spring in place for this first test and pressurized the pistol to 2000 psi. Then, I shot the same 3 pellets I’ve been testing all along:

14.3-grain Crosman Premier pellets
11.9-grain RWS Hobby pellets
14.5-grain RWS Superdome pellets

Below are the velocities on CO2 for the factory gun; then the velocities for the factory gun with the high-pressure air conversion; and finally the velocities for the gun with the steel breech, longer barrel and factory spring — all operating at 2000 psi.

Crosman Premier pellets
CO2 avg…………..Air in factory gun average…………..Air in long barrel average
448 f.p.s…………………..486 f.p.s………………………………………517 f.p.s.

I got 15 shots with this pellet and the longer barrel. They ranged from 504 f.p.s. to 524 f.p.s.

RWS Hobby pellets
CO2 avg…………..Air in factory gun average…………..Air in long barrel average
482 f.p.s…………………..526 f.p.s………………………………………564 f.p.s.

This pellet gave me 18 shots from a 2000 psi fill with the longer barrel. They ranged from a low of 548 f.p.s. to a high of 573 f.p.s.

RWS Superdome pellets
CO2 avg…………..Air in factory gun average…………..Air in long barrel average
455 f.p.s…………………..483 f.p.s………………………………………525 f.p.s.

Superdomes gave 14 shots on a 2000 psi fill. With the longer barrel, the low was 516 f.p.s. and the high was 534 f.p.s.

What have we learned?
Obviously, the pistol shoots faster with the longer barrel and no other changes. Adding the steel breech does strengthen the rear of the barrel, but it doesn’t add anything to velocity.

All 3 shot strings posted above started out slow and increased as the shots were fired. So, the pressure curve is about ideal when the fill is at 2000 psi.

The velocity increase from CO2 in the standard pistol to high-pressure air in the longer barrel is very significant. But by leaving the factory striker (hammer) spring in the gun, we’re not getting all this conversion has to offer.

Replace the striker spring with a heavier spring
The kit Rick Eutsler sent me contained two striker springs — both of which are stronger than the factory spring. I removed the factory spring and installed the spring that was the weakest of the two, though stronger than the factory spring. I wanted to keep the fill pressure at 2000 psi, and the strongest spring would not be the way to do that.

I filled the gun to 2000 psi and proceeded to shoot Crosman Premiers. Here are the first 8 shots.


The velocity dropped with almost every shot. Yes, there are a few exceptions, but the trend is generally down. What this means is that the new spring is too strong for the fill pressure of 2000 psi. The pistol wants to start at a higher pressure with this spring.

I decided to fill the gun to 2250 psi. This is above the maximum I wanted to use, but it illustrates the relationship I just mentioned and is worth a look. Let’s look at the velocities at this pressure.

Crosman Premier pellets
588 f.p.s. average, low 582 f.p.s., high 594 f.p.s.

Compare the above to the average velocity with the factory striker spring and longer barrel, which was 517 f.p.s. This is a huge increase of 71 f.p.s. The stronger striker spring gives more of a boost than the longer barrel by itself. But — and understand this — without the longer barrel, the stronger spring would only waste more air. This is a modification that requires all the components to work together. You can’t just pick one item and be done with it.

RWS Hobby pellets
640 f.p.s. average, 632 f.p.s. low, 646 f.p.s. high

The remarks are the same for Hobbys as they are for the Premiers.

RWS Superdome pellets
590 f.p.s. average, 580 f.p.s. low, 596 f.p.s. high

Same remarks apply to this pellet as to the others.

All three pellets gave me maximum shot strings of 10 shots when set up this way. Obviously, more air is being used and the volume of the reservoir has remained the same.

Evaluation to this point
We’ve taken this Crosman 2240 pistol from one power on CO2 to a much higher power with high-pressure air, a longer barrel, a stronger spring and a steel breech. These modifications cost a total of $150 over the cost of the initial pistol ($60). Is it worth it?

The answer will depend on who’s talking. Some shooters enjoy putting their hands on the parts of their airguns and making their own creations. Others look at the total investment and just want something that shoots well for the least amount of money. This 2240 modification is not for the latter group, because we still have to add a $60 RAI adapter and a $60 UTG Adjustable Stock. That brings the cost of the gun we’re modifying to a total of $330.

The next step is to try this modification for accuracy. For that, I’ll attach the adapter and stock, again. I think it has to be tested to at least 25 yards with a scoped gun.

WARNING: This conversion changes the operation of the pistol to use air at up to three times the pressure it was designed for. The parts that are installed are strong, but there are other parts in the gun that aren’t changed and could fail when subjected to the higher pressures. Pyramyd Air advises against making such a conversion. This report is for information, only.

Crosman 2240 conversion to air: Part 2

by Tom Gaylord, a.k.a. B.B. Pelletier

Crosman 2240 conversion to air: Part 1
R.A.I. Adjustable Adapter: Part 1
R.A.I. Adjustable Adapter: Part 2

WARNING: This conversion changes the operation of the pistol to use air at up to three times the pressure it was designed for. The parts that are installed are strong, but there are other parts in the gun that aren’t changed and could fail when subjected to the higher pressures. Pyramyd Air advises against making such a conversion. This report is for information, only.

Crosman 2240 air conversion
My Crosman 2240 has been converted to operate on high-pressure air.

This report covers:

• Where we are
• Before filling the first time
• Shooting the gun
• Crosman Premier pellets
• RWS Hobby pellets
• RWS Superdome pellets
• What comes next

Let’s look at what the conversion to air did for the Crosman 2240. Boy, was there ever a lot of discussion on that report! I think this may be one of the all-time most popular subjects on this blog.

Where we are
Here’s where I am with this subject. The 2240 is now converted. I plan to test it with 2,000 psi air today, and I do not plan to go higher. This is a test of what’s out there and some of the things that can be done with a 2240, but I’m not in the business of hotrodding this pistol. Many other folks are doing that very well; so, if you are interested in what’s possible, read what they have to say.

Today, I’m going to test the pistol with the conversion but with the stock striker spring still installed. In other words, if you simply screwed the tube into the gun and did nothing else (the front sight still has to come off to clear the tube), this is what you’ll get. I did change the face seal, which is why I disassembled the pistol in the previous report; but that wasn’t strictly necessary, since I am pressurizing to only 2,000 psi. I did it just to show how the entire kit is installed.

Before filling the first time
Before filling the gun, which is now done through the male Foster nipple on the end of the air tube, I put several drops of silicone chamber oil into the fill nipple. It came to me bone-dry, and I wanted all the seals inside the unit to get a coating of this oil. Then, I connected the gun to my carbon fiber air tank and slowly filled it to 2,000 psi. I say slowly, but as small as this air tube/reservoir is, it fills pretty fast. It probably took only 15-20 seconds to fill it all the way. You want to go as slowly as as possible to keep heat from building.

When I bled the air connection in the hose, the inlet valve in the air tube remained open and all the air bled out. So, I refilled it and bled it a second time. This time, it sealed as it should — thanks to the oil, I believe.

Shooting the gun
It was now time to test the gun. I had no idea what it was going to do, but I left my hearing protection off to hear if the first shot was loud. It wasn’t. Perhaps the gun is a little louder than it is when using CO2, but the difference is not that great. Of course, I used eye protection for the chronographing session, because the pellet trap is so close. I use a trap with duct seal to keep the rebounds down and the noise to a minimum.

Crosman Premier pellets
The first pellet I tested was the 14.3-grain Crosman Premier dome. I should add that I shoot only the pellets from the cardboard box, which is why I link to them, only. We were informed several months ago that Crosman planned to stop selling Premiers in the cardboard box and I stocked up on them. But I see they’re still available.

Back in 2010, I did a test of the CO2 2240 pistol, so I have the recorded velocities for this exact pistol on CO2. It averaged 448 f.p.s. with Crosman Premiers. On 2000 psi air, the first shot was 468 f.p.s. It increased to a maximum of 492 f.p.s. by shot 7 and dropped back to 466 f.p.s. by shot 15. At the end of the string, the gun was still holding 1200 psi of air pressure. The average velocity of 15 shots was 486 f.p.s., which means air boosted the average velocity of this pellet by 39 f.p.s.

RWS Hobby pellets
Next up were 11.9-grain RWS Hobby pellets. When the pistol was running on CO2, these pellets averaged 482 f.p.s. On 2000 psi air, they started at 515 f.p.s. and increased to 537 f.p.s. by shot 9. The velocity droped back down to 511 f.p.s. by shot 16. The average velocity for this string of 16 shots was 525 f.p.s. — a 43 f.p.s. increase on air. The remaining pressure was 1200 psi, once again.

RWS Superdome pellets
The final pellet I tested was the 14.5-grain RWS Superdome. When the pistol ran on CO2, Superdomes averaged 455 f.p.s. On 2000 psi air, they started at 470 f.p.s. and drifted up to 495 f.p.s. by shot 7. They dropped back down to 467 f.p.s. by shot 16. The average velocity was 483 f.p.s., an increase of 28 f.p.s. over CO2.

Notice that the gun performs similarly, regardless of what pellet was tested. The curve starts out slow, builds to the maximum quickly and then drops back to the starting point just as quickly. The three pellets gave a total shot count of 15, 16 and 16, respectively.

What comes next?
I can’t test the pistol for accuracy as it is right now because the front sight has no clearance to be re-installed. And the plastic 2240 receiver does not have a scope base on the receiver. Decision time.

I could get a steel breech for the 2240 from Pyramyd Air. While it will not accept the 2240 rear sight, it does have 11mm dovetails for a scope. That’ll work with the barrel that’s on the gun right now; but if I get a longer barrel, I’ll get a little more velocity from this same setup. So, I ordered a 14.5-inch barrel from an eBay vendor.

There are a number of different ways this can go with these parts, so I will wait to see what seems best once I have them.

WARNING: This conversion changes the operation of the pistol to use air at up to three times the pressure it was designed for. The parts that are installed are strong, but there are other parts in the gun that aren’t changed and could fail when subjected to the higher pressures. Pyramyd Air advises against making such a conversion. This report is for information, only.