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Air Guns Use it or lose it

Use it or lose it

AV compressor
Air Venturi high pressure air compressor.

This report covers:

  • Air
  • Problemo
  • Problemo number two
  • Super high pressure
  • What else?
  • CO2?
  • Multi-pump pneumatics?
  • Springers
  • Summary

A couple things happened to BB recently that he thought he would share, in case they ever happen to you. 


We shoot AIRguns — right. What do you suppose they need lots of? That’s right — superglue and Easy-Out screw removers. No wait — that’s after we maintain them, right? What airguns need lots of is air. BB’s Goldie that we just started looking at gets filled to 4,350 psi or 310 bar. 

No problemo; BB has not one but two large carbon fiber air tanks. And what do you suppose he uses to fill both of them? Right again — an Air Venturi high-pressure air compressor.


But BB hasn’t had occasion to fill his tanks for several months and recently he has noticed a puddle of oil under his compressor. He hadn’t run it; the oil just leaked out. Oh, oh! Does BB have to repair his compressor? Well, first he has to determine where the oil is coming from. So he tilts the compressor on its side, dumping the cooling water all over the garage floor, but he finds very little oil under the compressor unit. However, he wipes off all the oil and then fills the compressor with hydraulic oil. Following that he proceeds to fill his smaller air tank — the one that he knew would fill faster, just in case there was a problem.

As the compressor runs BB sees oil coming out around the oil sight glass window on the compressor. Wow! That’s really weird! BB used to be a maintenance officer in the Army and he knows mechanic-ing pretty well. Doesn’t do much of it, but as a theorist, he knows his stuff. And, in his professional opinion, oil coming out around a sight glass is weird. So he shoots an email off to Tyler Patner at Pyramyd AIR, because Tyler is BB’s go-to guy when BB doesn’t have a clue.

AV compressor sight glass
Sight glass.

While awaiting a response, BB disconnects his now-filled tank and connects his 98-cubic foot monster. This one will take some time. When he starts the compressor this time, though, the needle doesn’t rise. All the bleed screws are shut, so it must be an air leak. BB uses the time-honored hand test by running his hand along the air hose from the compressor end to the tank end and, when he gets to the Foster fitting of the tank hose, the air blast almost blows his hand off! Well, maybe not quite, but it could be used in a bathroom as one of those loud, obnoxious hand dryers.

Problemo number two

Hadda fix the tank hose’s Foster fitting before I moved on. So I looked inside the fitting. I saw a groove where an o-ring might have fit but there was no ring. Hmmm. Something had to seal the fitting so no air leaked out under pressure and beside bubble gum the best seals BB knows of are o-rings. And this fitting seemed to be devoid of one in a place that appeared made for one.

AV compressor Foster fitting
Foster fitting.

And where do you suppose the Foster fitting was made? Well, if it’s like 98 percent of the stuff I own, it was probably made in China. Or at least one of those countries that have adopted the confusing metric system. Fortunately, BB owns a large selection of metric o-rings for just such an occasion. So he fumbles around and finds the perfect ring that he then forces into the Foster fitting.

Connecting the now-sealed fitting to the adaptor was difficult which seemed like a good thing. And then, when it was connected to the pump hose again, no leaky. Once more BB was up and running.

Twenty three minutes later and this tank was topped off. And guess what? There was no more oil leaking out around the sight glass. It could be that the compressor needed to be used every once in a while to keep the seals fresh and doing their job.

Super high pressure

And guess what BB did? Time’s up. He adjusted the pressure setting that turns off the compressor, and as a result this tank now had 5,000 psi inside. Ooops!

Gotta get rid of some of that air. So BB fills — not BB’s Goldie — that would make sense. No, BB filled his Air Arms S510XS that fills to 250 bar. Why did he do that? Because BB really likes that rifle and it’s been too long since he has shot it. So, looking around for any good reason to shoot that rifle, BB comes up with a cockamamie plan to test some of the special .22-caliber pellets that he hasn’t tested in that rifle yet. The idea is legitimate, even if I had to go out on a limb to come up with it.

Hunting Guide

What else?

When I was a tanker in the Army I observed that if we didn’t run our tanks periodically they would start to leak from the same problem I just discussed. Do airguns have similar problems? Let’s see.

My Sig ASP20 no longer puts .22-caliber pellets out as fast as it once did. When I tested it back in 2018 it shot JSB Exact Jumbo pellets at an average 830 f.p.s. When I tested it on October 5th of this year it averaged 784 f.p.s. That’s a decrease of 46 f.p.s. Is that decrease due to lack of use? It’s hard to say with certainty, but it sure could be.


Do CO2 guns have this problem? They sure can! I used to recommend leaving gas in all CO2 guns all the time because I thought it kept the seals clean and working. That’s because I once bought a Crosman 111 pistol that hadn’t been touched for more than 20 years and it was full of gas. I got 35 powerful shots from that gun before it needed to be filled. And I put about 1,000 shots through that gun (it took several years) before it needed to be resealed.

But modern CO2 guns that use 12 gram cartridges have face seals that take a set from being compressed by the cartridge all the time. That wears the face seal out and they will develop a leak at that spot. So the answer for CO2 guns is sometimes yes and sometimes no. Pretty much it’s the bulk-fill guns that should be kept full and the cartridge guns that should be stored empty.

Multi-pump pneumatics?

If you have been a reader of this blog for any length of time you know that I recommend keeping one or two pumps of air in the reservoir of all multi-pump pneumatics. It keeps their valves closed and the seals inside clean. But what happens when you don’t use multi-pumps over a long period of time. Well, in my observation, as long as the valves remain closed and the seals hold in the air, very little degradation occurs. I wouldn’t take that one to the bank, though, because I’m just one person and I have only seen this on 30 different multi-pump guns or so.


Well, Yogi, BB even remembered you. So, do spring-piston guns go bad with disuse? Of course not! That’s why we love them!

Wait just a minute, cowboy. Like the CO2 gun the answer here depends. Depends on what, you ask? It depends on the gun. A Diana 27 properly lubricated is probably good for 2-3 decades of disuse. A Chinese mega-magnum, not so much. Turns out that if the mainspring is under a lot of pretension when the rifle is at rest (i.e., uncocked), the spring will still wear out. You will notice it by the buzzing feel the next time you deign to shoot the gun, and that is indicative of a bend in the mainspring, or something we call cant.

A TX200 Mark III mainspring is under very little pretension when the piston is at rest. The spring in a Diana 350 Magnum is under a lot. Stress is stress, however it comes. So be advised.


The lesson today is that mechanical items often need to be used to remain in order. Each one is different and it’s up to the owner to know his equipment and how to keep it running.

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.

49 thoughts on “Use it or lose it”

  1. Tom,

    I gotta love any piece of writing that has the word “cockamamie” in it. As far as words go, it isn’t highfaluting. Or hoity-toity.

    A question. I have a “steroided” Sheridan Blue Streak. I believe it is one a pevious owner steroided it with Mac1 parts. I’d prefer not to pester Tim with a question about an airgun he didn’t work on, so here goes. It of course should have two pumps in it when it is stored. The issue if that mine will not decock by holding the bolt open and squeezing the trigger. It dry-fires regardless. Incidentally, the bolt is about three times harder to pull fully than my other, stock, Blue Streak.

    So, store it cocked (and locked) with two pumps of air in it, or forego the air and store it uncocked?


  2. BB,

    I have one of the first AV air compressors. I have had a couple of different problems with mine. The first thing that happened to me was the burst disc gave up the ghost after just one tank fill. Now I have a few on hand.

    The other issue I have not figured out yet. It fills my tank OK fine until I reach about 3000 PSI and then it starts banging loudly. I immediately shut down. I think it is in the high-pressure cylinder. It sounds like it is rebuild time. I have not used it but maybe three times. I have mostly been shooting sproingers. I guess I need to shoot my gassers more often.

    I hope shootski does not have that issue with his ASP20s. I can well imagine getting a new gas spring for those will be fun.

    P.S. I have no official recorded data, but if my rememberer is working somewhat correctly, I seem to recall that you can often have failure when you use something also. Sometimes it wears out from use. If you are going to lose anyway, you might as well have fun in the meantime. 😉

      • And I’m wondering whether enough were sold to interest Sig’s former suppliers or aftermarket manufacturers to make parts for it, like the gas spring. Or perhaps a conversion kit to a steel spring.

    • RidgeRunner,
      Thank you for your wishes for my ASP20s. Thus far they have behaved themselves…as well as the SIG Whisky3 ASP Scope.
      I believe I recall reading that Ed Schultz said they need to have their Gas Spring exercised regularly so that there is no chance of “welds” or piston the head taking a set.
      But I am No Expert on Gas Spring powerplsnts.

  3. Excited to report that I scored a Winchester 353 (Diana 5) pistol to add to the collection. I passed up on a 427 that I thought may have been misused.

    Anyone out there have a Glock 17 Gen 4 BB gun? I am interested in buying one as a gift for a nephew who carries the 9mm variety as his police duty weapon. Thought it would give him the chance for cheap practice. Looking for any advice or tips along those lines with that specific gun. Thanks.

    • Roamin Greco,

      good old Diana LP 5… Those are nice. Easy to cock, easy to shoot, no fiberoptic sights anywhere.

      I especially like the bank-vault-like “ka-chunk” they make when you cock them 🙂


      • Thanks Stephan. I’m wondering if you know where I could get a set of front sight inserts for vintage Diana pistols and rifles. I have a place where I can buy them individually, but I’m thinking it would be great to have a set with each piece that has a front sight that has the replaceable inserts.

        I just realized…if my growing Diana airgun collection from the late 60s and early 80s is “vintage,” then I’m vintage, too. :o(

        • Greco,

          sorry, no idea. I think here in Germany, you have to buy the front sight tunnel and the insert separately. Weihrauch has a set (that might even fit on Dianas) but I haven’t seen one from Diana.


          • OK. Thanks, Stephan. I figured perhaps being in Germany, the country where these vintage Dianas were made, your local airgun stores might have these. Since they never seem to be sold with the rifles, they must go to the same place my left socks go. Somewhere in an alternate universe are all my left socks and the globe (“tunnel”) sight inserts from vintage airguns….

  4. BB,

    >>> use it or lose it <<<

    Yeah, it's a PM (Preventitive Maintenance) thing. There are a lot of things that need to be reminded of what to do or shown some love on a regular schedule to keep them happy and functioning properly. Things that see seasonal use (like the car's AC or boat batteries) are especially vulnerable to being forgotten in the winter.

    To help me remember, I have a general PM Check List that I go through on the first Saturday of every month and a twice per year Seasonal Check List. Some equipment (like airguns and cars) have their own maintenance list that is related to usage.

    I keep track of my airgun maintenance with pellet tins. Each gun is assigned a pellet tin and receives a thorough check/clean/lub when the tin is empty. It's usually a 500 count tin but a couple of my higher velocity rifles need more frequent maintenance (barrel cleaning) so I'll weigh out 200 pellets for them.

    Find it easier/more economical to maintain my equipment rather than have to replace it because of neglect.


    • Hank-

      Good comments all around. I’ll add one more that is seldom ever touched upon but can have a huge impact on your life. Once a year I pop off the front of all breaker boxes- houses, barns, shops, every last one- and tighten the circuit connections and every other fastener in the box. Hots, neutrals, grounds, romex or bx clamps; they all get tightened and every wire gets a tug to check the connection. Alternating current has a habit of causing movement and a loose connection will heat to a high temperature. Hopefully the damage is contained within the housing but all too often flames escape to catch the building on fire. Better safe than sorry.

      • PinO

        I have read that aluminum wire (used in quite a few houses in the 70s) has a tendency to “flow” under pressure. In other words, it does exactly what you described. After tightening, the metal tends to move away from that pressure, thus loosening the connections.

        Special connections were designed for outlets and switches to prevent that (forgive me, I do not know the design of them). There were a great number of fires that instigated the design work, of course. I wonder if copper,, or other metals,, might have something similar, dependent upon the thickness of the metal thus “squeezed”.

          • RR
            True. The main problem was as I mentioned, Once loosened the aluminum oxidized making the connection even worse. Copper will also oxidize, but since it isn’t as prone to “flowing” there is no oxygen available for it to do so within the joint.

            My question was more about other metals and whether they might also have that tendency and whether that might lead to loosening of screws because of it.


        • Aluminum wiring was popular back a while ago (70s?). I had a house with aluminum wiring, and to meet current building codes, I needed to have an electrician go through the breaker box and every switch, receptacle, and fixture in the entire house and squirt a special conductive grease or gel on the wiring connections to bridge any gap from the movement you describe.

        • Ed, if I remember correctly, my electrician described the problem with aluminum wires as aluminum expands when heated (more than copper) and then creates a gap in the connections when it cools and shrinks, which causes the electricity to arc.

      • Pacoinohio,

        Good point about the fuse panel. I check it over when I add a circuit but that is only once in a while.

        Have to add a dedicated circuit for a new CNC machine and dust collection system. I’ll go over all the fasteners and add checking the panel it to the list to do annually.

        Just a comment about this. The inside of a fuse panel is no place for those who are not comfortable/knowledgeable working with electricity. Best to hire an electrician do an inspection every couple of years.


        • I was in a 460v Federal Pacific box a number of years ago. Drifted a little wide while tightening a breaker. Sparky, sparky and the arthritis in my left arm was gone for about a week.

          • >>> Sparky, sparky and the arthritis in my left arm was gone <<<

            LOL! I accidentally shorted a piece of stainless steel to a 12 volt deep cycle battery and turned an area steel the size of a dime into light and heat. "Exciting!"

            Was working with a guy who used to work in the big hydro power stations. He showed me a fuse that was two 2x2x1 inch pieces of copper joined by four 2x2x1/8 inch plates (like a ladder). Said that you didn't want to be anywhere near it if it blew.

  5. “Well, there you go again,” FM. Preventive maintenance – very important for both airgun and airgunner. Couple weeks ago went to visit my childhood friend, also a Vietnam vet, who was laid low due to a stroke 3 years ago. Right arm and hand pretty much inoperative though he is able to do some walking and his speech has improved a lot. He was not much of an exercise type though he was no couch potato as he loved to work on cars, including restoring them for a hobby. He shared a pretty scary statistic based on a conversation he had with one of the doctors at the Veteran’s Administration facility where he is treated: if you wind up bedridden, every 18 days you lose FIFTY percent of the strength in your legs. Yep, use it or lose it. And, just like we try to be careful about what we “feed” to our fun guns, be it pellets, oils or greases, watch what you feed to yourself as well. It is all tied together.

  6. “But wait – there is more!” On the subject of proper storage of a CO2 gun, FM was also a believer in the “leave the cylinder/bottle in the gun.” Believe this is what the prior owner of the 38T did and don’t recall he ever had a problem. When he passed it on to FM, the gun kept on working fine for years. Had it re-sealed by Precision Pellet about 1-2 years ago and it worked fine until recently, when a leak developed at the piercing valve side – a fast leak.
    Note: always remembered to put a drop of pellgun oil on the cylinder or bottle neck seal before inserting it into the 38T.

    Dropped a little Barr’s Transmission Leak sealer on the trouble site and have been letting the revolver sit for a few days; keeping fingers crossed that will be enough to restore the seal face so it works as intended again. Otherwise, FM may just have to bite the pellet, order a seal kit and learn how to fix it himself. Airgunner, seal thyself.

  7. B.B. and Readership,
    Great Blog topic today!
    However, sometimes you don’t even get to use it before you loose it!
    For instance: today, 12/12/2022, I recieved a 5×8 mustard colored envelope in the Snail Mail (USPS) from Pyramyd AIR meter dated 12/08/2022. Inside I found an MOA cloth patch and a very nice MOA Challenge Coin. There was also a Thank You & Congratulations card for my participation in the Pyramyd AIR MOA Chalange. (I submitted my entries into all three levels using my SIG ASP 20 in .177 caliber shooting 10.3 grain JSB KnockOut slugs before the September 15th deadline).
    There was also included an exclusive coupon code for 15% off that CouldMaybe have been combined with free ground shipping on orders of $150+.
    Saddly the exclusive coupon code expired on 11/15/2022.
    A clear case of loss before use was even possible!


      • Mike in Atl,
        I believe you are correct that i could maybe do that!
        The question is why should I need to? It wasn’t (should not have been) a short fused project.
        The entire MOA promotion had a number of obvious flaws from the very beginning.
        Certainly not up to PA’s stated standards.


  8. “Deja vu, all over again”
    Seems we had this conversation before, and it reminds me I may be in a lot of trouble with my dormant airgun collection. Time to get hot!

    In bootcamp we went through the vaccination line one day. We walked between two lines of Corpsman that had what looked like paint guns in their hands and proceeded to shoot the vaccines directly into our arms … No needles!
    Now I seriously doubt they had 4,000 psi pressure behind those shots, may be wrong?
    But in my Aviation Hydraulics School we were taught to ‘NEVER EVER’ look for a leak, be it hydraulic or pneumatic, by using your hands to check for it. And we are only talking about 3,000 psi.
    Then they proceeded to show us pictures of people who did.
    One person’s arm was twice its size from being filled up with hydraulic fluid in less than a micro-second, and the other had a fingertip missing … cut off!
    Then they showed us how to use an ultra-sonic sound detector to look for pinhole leaks. and leak tech solution in a spray bottle for fittings and such although most are easily detectable by sight alone. Be very careful around high-pressure air equipment.

    • At my first job the guys liked to fool around with the shop air.

      They didn’t believe it was dangerous until I demonstrated (with a piece of pipe) that there was enough power to drive a 1/4-20 bolt completely through a 3/4″ board.

      Made an impressive hole and earned their respect… no more fooling around (with the air anyway 😉 )

    • Bob M,

      Dittos “”
      I cringed when i read that inspection technique. I also cringe when someone without the proper headgear/visor/goggles goes “LOOKING” for a leak; have observed the loose eyeballs (what remained) of an individual who used that flawed inspection technique.
      When I worked on Superheated Steam Systems we used broom handles to locate leaks — slices just like a cutoff saw makes.
      I’ll take a moment to share Dennis Quackenbush’s wisdom that a charged PCP should never be considered to be UNLOADED — EVER!


  9. B.B.,
    I find the part about break barrels (or any springer type) and pretension springs interesting. It’s something I’ve never really thought about. It would make sense to me that guns without a lot of pretension would seem better for longevity. My question, is there a way to tell which guns are and which are not under a lot of pretension? I assume this doesn’t really apply to gas rams/springs.
    Thank You,

  10. Okay, Tom, Hold up. I have been leaving CO2 in my airguns after reading your blogs. All use 12gr caplets. So are you now saying I shouldn’t do so? Here are my CO2 guns. Are any of them safe in your experience to leave ‘charged’?
    Crosman 2240
    Crosman 2300KT
    Crosman 1077
    Umarex Fusion Mark 2
    Umarex Beretta 92A1
    Crosman Mark 1
    Crosman 157
    Sig Sauer MCX
    Umarex Glock 19x
    Umarex Glock 19 Gen 3
    Beeman Qb78 Deluxe

    My pump ups are a pair of Crosman 102 Clickless rifles and the Seneca Dragonfly 2, what about those?

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