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Education / Training Crosman 114 – Part 2

Crosman 114 – Part 2

by B.B. Pelletier

Part 1

I made the picture big, so you can really see it. Crosman’s 114 is what little boy’s dreams are made of.

Back to the 114 today. As I mentioned last time, this is a bulk-fill CO2 rifle. What that means is that it doesn’t use any kind of disposable CO2 cartridge, as many CO2 guns do. Instead, a separate tank of CO2 liquid and gas is connected to the rifle, and CO2 is introduced from that tank. So, a short refresher on how CO2 works is now in order.

To fill the rifle, a separate CO2 tank is used. Every rifle was initially sold with a tank, plus spares were also sold. This tank holds about 10 oz. of liquid CO2, so it is called a 10-ounce tank.

How CO2 works
Carbon dioxide is a strange gas. At room temperature when liquid carbon dioxide (or solid carbon dioxide–which is also called dry ice) is confined in a pressure vessel like an airgun reservoir or a separate tank, it will evaporate until it reaches a pressure around 900 psi. Actually, at 70 deg. F. it attains the pressure of 853 psi when confined. At that point, no more gas will evaporate and the pressure will stay constant, as long as the temperature doesn’t fluctuate. The remaining liquid or solid will stay as it is, with the solid turning to liquid at this temperature.

If some of the gas is released, such as through a valve when an airgun fires, the pressure inside the vessel will drop and immediately more of the liquid will turn to gas. As long as liquid remains in the pressure vessel, the pressure of the gas remains more or less constant–except for one thing. As the gas is exhausted, it carries some latent heat with it. That lowers the temperature of the pressure vessel and the firing valve in the gun. In turn, that cooling effect lowers the pressure of the remaining gas to some extent. On a hot day, the temperature returns to normal relatively fast. But on a cooler day, the temperature takes longer to cycle back. When the ambient temperature drops below about 50 deg. F., the temperature of the gun takes a very long time to recover, and the pressure of the gas continues to drop as the gun is fired.

You can learn two things from this. First, CO2 regulates its own pressure. Nobody compresses it, in the traditional sense of the word. At least airgunners don’t. They rely on that high-vapor pressure to operate their guns. While the pressure is limited, it’s also self-sustaining, so it’s possible to get a lot of shots at a very consistent velocity–except in cold weather.

When the temperature is below about 50-60 deg. F., CO2 will chill the gun as it fires, causing the gas pressure to drop. It’s a warm-weather gas. Knowing that, you will be able to use it without many problems. As long as there’s some liquid remaining, the gas will maintain the same pressure. Once the last of the liquid is gone, the pressure of the gas drops straight off and the shots quickly become slow and unusable.

Now, apply the knowledge
CO2 liquid maintains pressure by evaporation to gas. CO2 gas does not maintain pressure and drops pressure rapidly. Knowing that, you understand that you want to have liquid CO2 in your gun. How much you have determines how many shots you can get at a sustained velocity. So, bulk-fill guns are designed to introduce liquid CO2 into the gun during a fill. With the 114, it’s very easy to do.

First, unscrew the protective cap at the end of the reservoir. If you have a gun that doesn’t have a cap, do something to protect this area, because any dirt that gets into the fill port can be blown into the gun during a fill. Many CO2 guns have a fine mesh screen to catch dirt particles, but don’t rely on that. Make sure no dirt is present to begin with.

The end cap is a screw that protects the fill port from dirt. Remove it to attach the CO2 tank.

Next, screw the separate CO2 tank to the gun. Now, hold the gun so it’s pointing straight up and the tank is pointing straight down. That lets the liquid CO2 gather in what is now the bottom of the tank (it’s being held upside-down), where it will be blown into the airgun. Hold onto the wheel on the tank and rotate the tank body so the valve will open. You will both hear and feel the liquid CO2 flow into the gun (the gun’s reservoir gets noticeably colder). The gas and liquid will stop flowing when equilibrium is reached, so you don’t have to do anything special. Today, some guns require the owner to weigh the reservoir before and after the fill to ensure that too much liquid did not get into the reservoir. The older Crosman guns didn’t have such a requirement. Under normal conditions (room temperature or higher), it’s nearly impossible to overfill the gun.

The tank is screwed to the end of the gun for filling.

Once the gun is filled–it only takes a few seconds–close the tank’s valve and unscrew the tank from the gun. If you got a good fill (the right amount of liquid), your gun will shoot for many shots before velocity drops off. This is the point at which the 114 starts to resemble a PCP. In fact, in a curious twist of irony, Crosman designed the Benjamin Discovery to use either CO2 or high-pressure air. Many confirmed CO2 shooters who had sworn they would never go over to “the dark side” and use air have discovered (pun intended) that filling with air to 2,000 psi isn’t much different than filling with CO2. You just get fewer shots and much higher velocity. They became reluctant converts to air power!

The modern way to full
If you don’t have a 10-oz. tank or you don’t want to invest in a 20-lb. tank to fill it when it gets empty, you can buy an adapter to fill these guns from paintball tanks that are easy to get filled at paintball shops. The adapters are available from those companies specializing in CO2 guns.

So, now we have a good idea of what a 114 is and how to fill it. Next time, we’ll look at the rifle’s performance.

author avatar
Tom Gaylord (B.B. Pelletier)
Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.

44 thoughts on “Crosman 114 – Part 2”

  1. Wayne,
    Hmmm…I think I remember BB saying the carbine kicks like a mule (paraphrased) so get the Garand…I say Hmmmm…. Myself, I like the looks of the carbine and wonder if a hocky knee pad would work attached to my shoulder?


  2. BB,
    I agree with Mr B. Most excellent tutorial on CO2!!! Where do I send the check? You've cleared up some confusion for me. I'm getting a better handle on the CO2 experience, now.

    One thing I've noticed is that after a fill, and I get my Talon SS's two refilled 12oz bottles home the liquid doesn't seem to slosh around very much. One time I thought I had a slow leak and I thought the tank was near empty because I couldn't feel any liquid sloshing but the refill station said the tank was nearly full when I took it there to have it checked. Maybe I need a scale to weigh them.

    I keep one bottle on the gun and one as standby, which can be for as much as a month. When I go to the standby I never know if there is anything or enough in it until I hook up the chrony to show fps. And even then I don't know if any leaked out or how long it will last. On air, with a scuba tank, I know exactly how much is left and how close to a refill I'm getting.


  3. Chuck,
    I don't have a bulk fill CO2 gun yet, but I use 20 oz. CO2 bottles in my welder and I weigh them most of the time. I usually get from 18to 24 oz. I take them back when it is less than 17. Some operators will bleed some gas off to cool the tank and then refill. When you find that guy, ask for his work schedule and try to get him every time. It also helps to cool your tanks in the frig or freezer and keep themk cool until you get to the store.

    I got tired of pumping and bought an air tank. When I had it filled the guy said it would be a "hot " fill. If I wanted a "cold" fill I would have to leave it overnight. His explanation made sense, so I'm curious why I haven't seen it mentioned on this blog. Does it only happen on the first fill?

  4. MCA,

    Being a chemist I feel qualified to answer the question about heating on filling. When you pump a gas into a cylinder, the gas will heat. In part, the heat depends on how much of a pressure change. So when pressuring a tank from 0 psi to say 3600 psi, it will heat up more than if the tank was pressurized from 2000 psi to 3600 psi.

    No doubt the reason for holding the tank overnight is to let it cool back to room temperature. For a 3600 psi tank, the tank would drop to maybe 3450 psi when cool. The vendor would then top it off to 3600 psi again. It would still get a little warmer, but after cooling again the pressure might drop to say 3590 psi. Unless you had a really precise gauge, you'd never notice the second pressure drop.

  5. MCA,

    my local SCUBA shop will fill my tank while it's in a tub of cool water. I don't know if I ever get a full pressure fill on it as I don't have the necessary apparatus to measure it's pressure but it's always above the 2,000 psi I require for my Discovery (based on the guage reading when filling the rifle). The tank is a "low pressure" steel tank and only rated to 2200 psi or so .


  6. Chuck,

    B.B. will have to tell you all about the fire arm he traded me… Like I said, my "I'll take it" was without the full explanation of what it was!!

    Tom said "my collection needed one of these"… and I said "you bet cha"…

    So, the ropes were cut.. and the antidote for fire ant bites was applied.. what else are friends for??

    I'd love to know what I got too!!! ..
    but Tom did say it has very little recoil.. and it's a "blast" to shoot!! … just what I need to keep from being invaded by Chipmunks if the economy fails and they go crazy stealing my food!

    Wacky Wayne, MD. Ashland Air Rifle Range

  7. B.B.

    First.. safe travels!!… and thanks for welcoming me into your home! .. and your front lawn..

    I too, want to thank you for the great explanation on how CO2 works!

    It seems like the perfect way to shoot for those who want low power, lots of shots, don't mind the cost, and most importantly… live in a warm climate.. or maybe always shoot indoors… or haven't got into high pressure air yet!

    … sort of a stepping stone as it were..

    A stepping stone I have already passed by.. That's what I should have had as a kid in southern Calif in the 60s'…

    Wacky Wayne, MD. Ashland Air Rifle Range

  8. Brown truck dropped off my PA purchased reconditioned 1377c on Monday. Got to shoot it Tuesday after cleaning the barrel a bit on Monday evening.

    First 30-shots it was obvious why it got returned. Darn thing shot way left too far for adjustment. Then it starting slinging them in a wide 3" random pattern. for the next 90 or so shots. Then it started to group a bit with the rear sight pushed all the way to the right this time. A shift of several inches at 15-yards. Wow what a change.

    Then it started to walk back to the left and settled down (for now anyway) with the sight almost dead center.

    Chrony tested the first 120 shots. It got a few drops of oil (Pellgun of course) before the first shot. It was shooting hot. Five strokes was getting 450fps which is hot for a stock 1377c I think. Then it settled down to about 430 which is still good. After 60 shots at this power level I put in some more oil and got 20 more high power shots with an average of 454 fps with ES of just 15.82. Not bad. My other 1377c that is well broken in does 432 fps with ES of 13.99 with 5-pumps.

    By this time the barrel seems to be getting broke in and it is drilling quarter size holes (actually vertical lines) at 15-yards using iron sights. OK still getting a few fliers… but I've only used the ultra cheap CR competition pellets. Better pellets will no doubt yield better results.

    Flipped the iron sight and am using the peep sight. The factory hole is drilled for young eyes and short arms. So I punched mine out to 1/16" which is large and works well off hand or with the 1399 stock attached.

    The pump, bolt, and trigger action was so rough it felt like the gun was full of sand. After all the shooting done to date everything has settled in and is getting tolerable.

    The plastic front sight is bent… looks like it came out of the mold bent. And the barrel spacer is missing which allows the barrel to clank when you push on it. Does not affect accuracy though. The bent sight is a bit disturbing to look at.

    Unlike my other 1377c guns it shoots high. Taking the rear sight all the way down is just barely enough to bring it to zero. Not worried in another hundred shots this could change again.

    Over all well worth the discounted $30 price tag. Now I have one scoped and one with iron sights. Nice combo for quiet back yard plinking.


  9. B.B.

    Thanks for the explanation of CO2. How much of the volume of a new CO2 powerlet is liquid?

    Wayne, of course, the M1 carbine. My information is that it should be very pleasant to shoot.


  10. MCA,

    Ity appears you are talking about a fill of air. When high-pressure air enters a scuba tank, it heats the tank from the heat of compression. If you fill the tank to 3,000 psi and come back an hour later, it will read 2,700 psi, or so. A cool fill would be one where the operator comes back and tops off the tank. You would get more air with a cool fill, but it takes longer to do.


  11. Chuck,

    No need to go back to the store to check your tank. Hold it upside down, so liquid comes out and depress the valve momentarily. Do not do this with your hands in the way or you will get frostbite.

    If you see snow coming out of the tank, there is still liquid inside. I check all my tanks this way. But I have manual valves on my paintball tanks, so I can open them without endangering my fingers.


  12. Matt,

    You are going to regret asking that question. "How much CO2 does a 12-gram powerlet hold?"

    Well, let's see. How much does a 20-pound tank hold? How many gallons fit in a 30-gallon gas tank? How much does that five-pound weight weigh?

    The rating of each CO2 pressure vessel is the net weight of the product inside. Because of manufacturing tolerances, there will always be variations, of course, but a 12-gram CO2 powerlet is supposed to hold 12-grams of liquid CO2.


  13. BB,
    For us dinosaurs, 12 grams = 0.42oz.:). Sounds a little piddling when its converted (maybe thats why they used the metric system). 10oz should do hundreds of shots, but I'm gessing it won't scale linearly.

  14. B.B. or Mrs. Gaylord,

    Is it true that the American Airgunner Show will now be shown on the Versus Outdoor channel?

    Since I don't get the Sportsman Channel but do get Versus this could be great news!

    I've heard the airdates/times are as follows:

    VERSUS OUTDOORS 360degrees

    Wednesday 7:00am EST November 4th 2009 = Episode 3 Season 1 – Pneumatic Airguns

    Operation and maintenance of all types of pneumatics, hand pump operation, operating air compressors, snuffing a candle with a pellet

    Wednesday 7:00am EST November 11th 2009 = Episode 4 Season 1 – CO2 episode

    Co2 operations and maintenance, shooting action rifles, shooting accurate CO2 rifles that also run on air, safety

    Wednesday 7:00am EST November 18th 2009 = Episode 5 Season 1 – Ballistics episode

    100-yard airgun shot, wadcutter versus domed pellet accuracy, pellet penetration in soap, big bore penetration is flesh and ballistic gelatin, making ballistic gelatin

    Wednesday 7:00am EST November 25th 2009 = Episode 9 Season 1 – Airgun Action Targets

    Making reactive targets, how to shoot airgun silhouette, big bores on reactive targets, how to make a field target


  15. B.B.

    Very funny. 🙂 I knew the amount of CO2 but I didn't know that it was all liquid initially. Maybe some of it was gas. I noticed that I had never detected any sloshing in a new powerlet. I guess that was one clue that the volume was all taken up with liquid, and there's no way to test an open powerlet….


  16. Kevin,

    Versus asked to air a couple episodes. Maybe they changed their mind & decided to offer 4 time slots instead of 2.

    Incidentally, we don't get the Sportsman Channel, either.


  17. B.B.,
    Funny thing happened to me last night. I got an idea.

    Was wanting to see the clock across the room so I picked up my glasses and put one lens in front of my right eye to put it in focus. Funny thing was I could see two clocks. Further by moving the glasses a bit up down and back and forth the second clock could be lined up with the clock image.

    Then the though hit me. Is this the same as parallax in a scope?

    It sure seems the same to me. If it is then it is a way for people to do a home experiment to see the effect with dramatic results.


  18. Pcp4me,

    I cann't remember if I told you that Crosman just replaced by Discovery. Much nicer wood, a better feeling trigger and a stack pellet on pellet at 16 yards shooter which was hard to do with the first one. Again thanks for your help.

    A very big thank you to Crosman for the way they stand behind their products. A class company.

    Mr B.

  19. Mr.B.,
    Congratulations on the Disco. Man they replaced my and repaired the replacement and I've tweaked it and it will not stack pellet on top of pellet at 16-yards. But it will give me 30-shots that will stay in a kill zone and that is good enough.

    My first one had a beautiful stock but would not group at all the second one is just plain. Not ugly not pretty… just plain.

    And hey I had one of those antique rubber fingers in my desk drawer. it does make a functional dust cover for the Disco pump.


  20. B.B.,

    One time deal or not I get to see the show.

    Who do we have to write to in order to increase the odds of this getting a permanent time slot on versus? Sponsers? Versus? Producers?


  21. Ransom,

    I did a search for a report on the Bam 30-1 (and searched for Bam B30) and found lots of pages where people were commenting on the gun but if B.B. ever did an article on it I couldn't find it.

    Have you gone over to the chinese forum. Even though the Bam 30-1 is a heavy gun there are alot of people that really like them. Do a search over there and you'll find lots of good info.


  22. Randy,

    I can fill you in on the B30 having gone through 3 of them. The quick summary is that it is a copy of an RWS 48 with terrible quality control. I expect that is why PA dropped the whole line.

    However, if you get it tuned or can tune it yourself, you will have a $500 gun according to great retired tuner, Bob Werner, and that has been my experience. It is a terrific rifle after the tune except that the adjustable front sight will not stay on, and the trigger is a little stiff. However, you will want a scope anyway, and I have not exhausted all the trigger adjustment possibilities because the rifle shoots so well.

    A B30 used to run about $150. A professional tune job with shipping well get you about double that. Rich Imhoff does a great tune, and I bet Mike Melick could too although I have not asked him about this particular rifle. So, it is essentially a toss-up between this rifle and an RWS 48 as I see it.


  23. Matt,

    The physics of the gas dictate that there is ALWAYS gas in any vessel. But the weight of the product equals 12 grams, nominally. Don't ask if some of that weight is taken up by the gas, because the answer is yes. the weight of ALL the product is 12 grams, nominally. When I say nominally I mean that they set tolerances low and high and each powerlet they sell has to be within those.

    So when you buy a 12-gram powerlet, you are getting 12 grams. What that does for you is determined mostly by the gun and partly by how you shoot it.


  24. Aamir,
    You have a very good question there and I'm sure it has been answered on this blog somewhere.

    Since you are limited to only two pellet types I think your question should be:

    Is a wadcutter (Gamo Match) better for shooting birds or is a pointed pellet (Gamo Pro Magnum) better. And I like to include domed pellets in this question, also.

    I don't know the answer to this question but someone on this blog will answer it, I'm sure.

    But, Aamir, please be sure of your local laws about shooting certain birds. Some may be protected by law. I think you sound like the type of person to have already checked this out, but I just needed to make sure for my own benefit.

    Also, I think this question and all questions should be added to the current post on this blog.

    Always go here to get on the current post:


    I will move your question and mine over there for you and you can join us over there, too.


  25. Aamir,
    There are some comments about your question on the current post "Healthways Plainsman BB gun – Part 1" that will interest you. I hope I was able to direct you to it ok in my previous comment on this post.


  26. Aamir,

    A rule of thumb that I've used is flat for feathers and pointed/domed for fur. Of course what your gun shoots the best at the disatance you're going to be hunting is what you want to use.

    Mr B.

  27. Niklausk18,

    Welcome to the blog.

    I don’t know about the adaptors you linked to Wal-Mart and Sear aren’t really airgun stores, so I doubt they have anything that meets the specs you need.

    If what you buy doesn’t work, I can direct you to someone who makes it right.


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