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Education / Training What does dieseling mean? – Part 2

What does dieseling mean? – Part 2

by B.B. Pelletier

Part 1

WOW! This subject, which I felt was going to be too simple for many of you, has really raised a lot of good questions. I will try to address them today.

If the fuel is burned, why does the gun keep dieseling?
Thus asks Nathan, and it’s a good question that has several possible answers. And, I will conjecture a little to explain them, which means I am not certain of what I am saying, either. First point: the amount of fuel that gets burned each time is very small. It doesn’t take much to sustain it for years. However, if the fuel does get burned in the compression chamber, why does the gun keep dieseling?

One possibility (this is conjecture) is that all the fuel doesn’t burn, that only a small fraction of what’s there actually combusts. That would explain why you can keep on burning fuel shot after shot.

Conjecture No. 2: several writers, including the Cardews, have suggested that the lubricants in the spring tube behind the piston contribute fuel by slinging their lubrication onto the walls of the spring tube. When the piston is withdrawn in cocking, some of this lube is not scraped back by the piston seal and remains on the walls to go forward with the piston as the gun fires Remember, the piston seal works best when going forward. There is a continuing replenishment of lubricant ratcheting its way forward to the compression chamber through the action of cocking and firing. Combine this with the other explanation of all the fuel not burning each time, and you have a relatively self-sustaining fuel burning engine.

Is fuel even necessary?
For years, I was satisfied with this explanation until I read what the Cardews did to try to stop the burning. They rebuilt a powerplant after drying it completely. They then lubricated it with dry graphite powder. They cleaned all oil from the pellets they used. The gun sounded like a “bag of washers”; but, even after all of this, they could still smell the acrid smoke of combustion when the gun fired! Something was still burning, though there didn’t seem to be anything left to burn. They left this observation unsolved.

The nitrogen experiment
The Cardews tested a .22 caliber Weihrauch HW35 that was getting 636 f.p.s. with a 14.4-grain pellet. They put the rifle in a large plastic bag and sucked out all the air. The left it that way for 30 minutes to get all the oxygen out of the piston seal, then they filled the bag with nitrogen, which doesn’t support combustion. The muzzle was poking out of the bag, but they resealed it with a plug after each shot. They shot this gun in a pure nitrogen atmosphere for several shots and recorded a velocity average of 426 f.p.s. The gun had only 45 percent of its initial power (energy, not velocity) when it was not permitted to burn fuel. Then, they took the gun out of the bag and continued firing it and the velocity rose back to the initial figure. This is their proof that combustion happens with every shot. Not only that, but with some guns that have tight velocity spreads, it is also very well regulated!

Buy the book!
Don’t think that I have told you everything that’s in the Cardew book. Indeed, what I have told you comes from just 4 of the 235 pages.

Next question: Light or heavy pellet?
I have tried to follow the intense thread of discussion that Squirrel Killer started when he told us of his success with 16.1-grain Eun Jin pellets in his .177 Gamo CF-X. To that I responded that many shooters (not me) feel that heavy pellets will damage the mainspring of a spring gun. And, then, we were off to the races! To Squirrel I say – keep shooting the pellets that work.

For the rest of you, I do have some information about the effects of light and heavy pellets on detonation. Light pellets seem to make a gun detonate; heavy pellets don’t. This has been my observation after years of shooting. Anytime I forget to load a pellet into a rifle (yes, it happens to me, too) and the one time I loaded a .177 pellet into a .22 Beeman R1, I got a detonation. Any pellet that is obviously too small for the bore is another almost certain candidate to detonate. Sometimes, I get detonations from pellets that seem to fit well but are extra light. This is one good reason why I do not like Gamo PBA ammo.

From my observations, I would have to say that backpressure seems to stop the detonation. When I shoot a very powerful airgun, I always start out with heavier pellets, though until I read Squirrel’s story I never thought of using super heavy pellets in spring guns.

Here I must break off the last part of the report into part 3.

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.

73 thoughts on “What does dieseling mean? – Part 2”

  1. BB,i have seen on a few webb sites that tell people,when a gun is dieseling to fire a heavy pellet through the gun and it will in most cases stop it,i have tried this my self and it has worked,then if people say fireing heavy pellets damadges the gun,if it stopes the dieseling in spring powerd guns this cannot be a bad thing in my eyes,so if dieseling causes spring damedge,and heavy pellets stop it,witch is worce?what came first the chicken or the egg?

  2. Thanks B.B.,

    Now I think I get it:

    – All spring guns diesel. Dieseling is a combustion event using available oil/fuel in the chamber, and this is not bad, it is actually and expected and necessary event. Without it velocity falls off.

    – A Detonation is a diesel event, which is a very STRONG combustion (explosive) event.

    – Detonations are BAD!!! Detonations can cause damage, re-cocking of mainspring, etc.

    – “Dry firing” or using pellets that are too light can increase the potential for Detonation, because of the mixture of the available oil/fuel with the extreme pressure/heat generated by the piston which does not incurr much back-pressure.

    – Heavy pellets make Detonations unlikely due to increased back-pressure, and therefore, should not harm and may even be considered a positive.

    – Squirrels don’t have a chance now that Squirrel Killer is using 16gr pellets (lol).

    Thanks for the information on this, I feel more secure now. Looking forward to your experience with the 16gr Eun Jins. Liked your idea of using your Whiscombe to compare 16gr .177 and .22 pellets using the same powerplant. Should be interesting.

    Thanks again

  3. p.s. – Maybe, in the cases of “dry-firing” and a loosely seated pellet, there is more of an oxygen-rich environment for the chamber to draw upon, since there is less of or no obstruction in the loading port. This could increase the magnitude of the detonation. Just conjecture also.

  4. BB and squrrel, i almost thought i found a flaw with your reasoning, but i think its still all good. i would have thought increasing the back pressure would have caused an increase in total pressure, which in turn would have increased heat.
    but now, i believe the increase in back pressure is a dampening effect which lessens total pressure and therefore lessens heat. in the example used where you could cock the springer and then perfectly seal or contain the barrel or chamber, the piston should not move and you would have constant pressure and heat. its probably the explosive energy and ability of the piston to move forward easily which produces a high pressure (and heat) spike at the transfer port which increases detonation potential. the more freely the piston can move, the higher the spike, so you could therefore get detonations with lighter pellets also. great job guys!!!

    • What you are all suggesting here in this thread about light pellets and dieseling makes absolutely no sense! Heavier pellets = higher backpressure = increased pressure = higher temperature = detonation, JUST LIKE IN VEHICLES! The bang you may hear with lighter pellets is not because of the detonation or dieseling, it’s because the lighter pellet travels faster, above the sound barrier = “bang” noise. Avoid using too light pellets to avoid piston smashing against end point and avoid using too heavy pellets to avoid detonation of oil residues.

      • tedbouras,

        Welcome to the blog.

        I’m sorry this makes no sense to you, but it is the way things work. Maybe the lack of back pressure the lighter pellet has allows the piston to slam forward faster and that causes the more certain detonation?


        • Dear B.B. Pelletier, thanks for your welcoming, airguns is a hobby that I have much love for and I find this website & blog a useful source of information.

          I cannot accept this light pellets & detonation correlation as it goes against my engineering background and whatever experience I have with spring airguns. Backpressure in a DIESEL cycle is a prerequisite for detonation – its physics, you cannot deny this. No, I don’t think piston slamming forward faster is a reason for detonation – my explanation on this would be somewhat lengthy and perhaps inappropriately “technical”, I feel nobody here would be interested in reading it. I think that such technicalities (thermodynamics assorted bla bla etc) should be kept to a minimum if not avoided in this discussion.

          At this point I must note that I do acknowledge you being an airgunner significantly longer than I have (obviously) and therefore I cannot overlook any assertion of yours based on personal experience and observations (which I have no reason to doubt).

          I would be very much interested in your responses, thoughts or comments on the following:

          1. Could you please explicitly describe a lighter pellets detonation phenomenon (sparks, bang, smoke?) as well as the heavier pellets cured situation (reduced or lack of sparks, bang, smoke?). Is it possible to upload a youtube video demonstrating this?

          2. Have you encountered lighter as opposed to heavier pellets detonation with every spring airgun model or brand that you’ve ever used?

          3. For a given airgun consistently detonating on light pellets as opposed to heavier ones, have you tried using same weight light pellets of different brands instead of going for heavier ones to cure this? Could you provide some more info on your “detonation curing” experimentations with pellet weights and brands?

          4. Tom Gaylord, a well respected figure among airgunners from what I understand, suggests that spring guns tend to work best with lighter pellets (video link https://www.youtube.com/watch?v=besy4q39S5M?list=PL74FF159FF533DDFF watch @ 03:35). I’m sure we wouldn’t have said that if he too like you considered lighter pellets a source of detonation related issues. What are your thoughts on this?

          5. To my notion, heavier pellet = higher resistance through the barrel = higher backpressure = higher temperature of compressed air O2 = excessive lubricant droplets detonation. In the same previously mentioned video, Tom Gaylord discusses the effect of thin (and therefore easily deformable when traveling through the barrel) vs. thick pellet skirts as opposed to our discussion of light vs. heavy pellets. An easily deformable pellet skirt (thinner skirt or softer lead alloy) regardless of actual pellet weight and apart from the entailed flight stability/ accuracy issues could potentially be an additional source of friction and therefore resistance. Therefore thin skirt = easily deformable skirt = higher resistance through the barrel = higher backpressure = higher temperature = excessive lubricant droplets detonation???? Both light and heavy pellets can have thin or easily deformed skirts due to design or utilized lead alloy??? Do you think this explains your observations of light pellets being a cause for detonation?

          • Here is a very interesting (and somewhat technical enough) article that I’ve just found:


            ….it more or less proves my point. Quote from the article:


            I once set out deliberately to make an air gun detonate, and eventually succeeded through a com bi na tion of a very high start pres sure and very heavy pel let, in com bi na tion with an ex tremely beefy main spring nec es sary to gen er ate the huge pel let start pres sure,…”.

            I would also like your comments on the contents of this article as well, thank you

            • BB. Pelletier apologies, didn’t realize you actually were T. Gaylord, it was never my intention to play smartass or be disrespectful to you or any other reader/ contributor of this blog.

              1. I still would like your comments on the UK airgun world article I linked here whenever you find the time.

              2. Matching pellet weights with spring data (energy storing capacity) is the way to go in this case I believe… Spring data however are rarely available for most springers I’m interested in buying… Do you have assorted tabulated data you could share (energy vs pellet weight)?

              3. It is my intention to buy a Beeman P1/ HW45 2 stage .22 cal airgun (have read this blog’s assorted articles). What is your suggestion on the most appropriate pellet weight to minimize excessive dieseling?

              4. I am also looking to buy a new spring air rifle and found an interesting one rated at 24 Joules. Again, what would your suggestion be on the most appropriate pellet weight in minimizing excessive dieseling?

              5. A friend’s Beeman P1/ HW45 2 stage .177 cal airgun sort of dieseling occasionally with a particular pellet weight and brand on power level 1 stops doing that on power level 2 for the same particular pellet weight and brand. This in my mind is the equivalent of using a lighter pellet on power level 1. I have witnessed this myself, what are your thoughts on this?

              • Tedbouras,

                For a 24 joule spring-piston rifle I would look at a JSB 15.89-grain dome. I think the 18.1-grain domes are too heavy for accuracy.

                Your comments about matching springs to pellet weight are the same things I mean when I say to shoot pellets that feel best in any powerplant. If the pellet causes vibrations or noice, I wouldn’t use it.

                As for the HW 45 detonating (remember Cardew — they all diesel) I was told by Beeman to dry-fire the gun on full power a couple times. In .22 there is on;y one power level, so just dru-fire it. That should stop the detonations. That is how Weihrauch fits the PTFE piston seals when they are new.


  5. once again, these back pressures are minimal at these wieghts anyway, but they are enough to help quell detonation. i’m sure airgun manufacturers encounter this at the design stage of their powerplants. there are probaly formulas that involve forward piston thrust and chamber size/capacity, with transfer port size to determine pressure and heat, to help them develope powerplants. car manufacturers encounter this also, along with any piston or pressure driven invention. airgun manufacturers can’t produce airguns that continuously detonate with average wieght pellets. they can calculate consistency, but can’t control us on whether we put a pellet in the loading port, or what weight pellet we use, or if we are changing out main-springs and tuning guns ourselves and blowing their model. you are probably safer going heavy than light, and i don’t see a problem with the 16gr, but there is probably a threshold before something doesn’t conform to their original model and gives.

  6. if gamo is going to produce pba ammo to use in their guns, and this can increase detonation potential, they better stand behind their warranty. or maybe they have foreseen this and have built a powerplant they have confidence in. their old manuals used to say dry-firing was ok, newer manuals say avoid dry-firing.

  7. haha, it looks like gamo is still learning their guns potential…pathetic. and to an anonymous commenter, the increase in back pressure does cause more pressure, but of a different type…when you use a light pellet, the piston slams forward very fast, and this causes friction on the piston and the piston tube. when you use a heavy pellet, there is more back pressure, which means the piston will slow down a little, but the air build up will be greater then when there is a light pellet. in order for a build up of air pressure like that to burn, the fuel would have to mixed in with the air(like a car). i still dont understand how the increase in back pressure can break the spring…all springs, whether you use a light or heavy pellet, will have back pressure…how is just a couple of grains more going to do much more damage? if anyone can explain this to me a little more, i would appreciate it.


  8. since a gun model most likely uses the same powerplant for its .177 and .22 (and even .25) versions, i would assume the threshold would be beyond the heaviest .22 or .25 pellet before anything has to “give”.

  9. Dave and everyone,

    Just to clarify this, the discussion groups I have read where heavy pellets were said to destroy mainsprings were saying that the heavy pellet caused rebounding of the piston. That sent a shock wave through the mainspring.

    I don’t remember if they attributed heavy pellets to detonations or just to piston bounce.


  10. Yes but even the rebounding of the piston, and subsequent shock-wave, would seem like a normal event, not necessarily amplified by heavy pellet usage.
    I imagine my piston bounces at the end of every stroke, otherwise, jesus that would be a hell of alot of energy that just stopped completely, this would seem harsh. I would much rather run my car into another parked car, than a forified brick wall.
    Seems like the piston slamming harder at the end of the stroke, would produce a more profound shockwave. Almost like watching a “slinky” (if anyone remembers this toy) work/walk. The harder you force one end of the slinky down on a solid surface would send a wave back in the opposite direction which would form compression which would help recoil the opposite end up and over. If the proper amount of energy wasn’t initially supplied to this toy, or lets say your surface was soft (energy absorbing) it wouldn’t work.
    If the heavier pellet dampens this force, I would assume it would slow it down, but thats it. These weights are miniscule compared to the force of the piston, they are not stopping the piston midway in its tracks, it would more like a miniscule (and I mean miniscule) cushioning effect. A 30+ lb cocking effort on a mainspring should care less about the pellet. If I was a mainspring, I would say “please, please” make sure you put something in the loading port, and the more substantial the something is the better.
    I see guns like the new Hammerli X2, which has quick-interchangle .177 and .22 barrels. Safe to say the powerplant doesn’t care if the pellet is a heavy .177 or an average or even mid-heavy .22, just as long as you have the correct size pellet . Hammerli is not the first to do this, so heavy pellets should be a non-issue. As long as you can get good velocity and accuracy, I say go for it. If our springers are this sensitive, then why is this a popular powerplant for many manufacturers. Anyone that refutes this, step up and give me diagrams and hard proof.

  11. maybe its a marketing tool, to discourage people from using heavy pellets. if a person can use a 16gr .177 pellet in their magnum springer, why would they then need to ever buy a .22 caliber springer. sure the wound channel would be larger with a .22, but there is not that much difference in size (1mm) between .177 and .22, its weight, velocity, and energy absorption that counts at that point. if you get shot in the head with a 9mm firearm or a .40 caliber firearm (which i believe is a 10mm round), you tell me which one hurts more as they both more than likely lead to your death.
    being bigger and slower isn’t always good either. if I get hit in the head with a cast iron pan, thats on thing, but if someone melts that same cast iron pan into a hammer or pick axe, i’m done for.
    maybe thats why gamo pulled their .22 caliber line from the US once they started manufacturing 1000-1600fps guns. they knew people would use heavier pellets to keep from going subsonic, and once people started using heavier pellets they would dispatch their prey more effectively. maybe this is also why you can’t get some magnum .177 springers like the Hammerli storm in .22 caliber, they knew you would eventually discover the 16gr pellet, so its not worth their time and energy to produce a bigger caliber.
    this is all just hypothesis and conspiracy theory, pay it no mind.

  12. NONE of the manuals of my guns say “do not use heavy pellets” or “use pellets from this weight range to that range”. they DO say “do not dry-fire”. if “dry-firing” is at left end of the spectrum of what “not to do”, and THE POINT PAST the “heaviest pellet your gun can shoot while achieving good velocity, accuracy, and satisfaction” would also be considered what “not to do” but at the right end of the spectrum,… just do whats in between leaning toward the right and you should be fine.

  13. it seems like the best way to explain the ppl that say don’t use heavy pellets is this-its like they just purchased a really big, heavy duty pick-up truck, but they just drive it around every once in a while, even though its actually made for work. they dont want to get their stuff dirty(in the case of a truck), even though it can handle it.(like the pace salsa commercial where they say”thats the guy that gets his salsa from NY”) lol, but thats just my opinion

  14. exactly!!! that slinky example does for me…”The harder you force one end of the slinky down on a solid surface would send a wave back in the opposite direction which would form compression which would help RECOIL the opposite end up and over”.
    that recoil would be powerful if its successively carrying the opposite end up and over for a slinky and the materials its made of. and that energy would be dispersed over an arc. my god, linearly, imagine whats happenning inside the gun with those springs. its not surprising springs break, knot, or are ripped from one end or the other at these magnum forces. if this damage is a more prevalent problem, now that we have more magnum springers then its a design/material/construction/over-tuning issue in the quest for speed. bb has done topics on old/pre-magnum era springers with springs that have lasted for long periods. if you are busting the spring on a new magnum springer within a short period of time, the gun is its own worst enemy and is a detriment to itself. i would almost like to see repair numbers for non-magnum springers vs magnum springers, the truth would be there. don’t get me wrong, i love magnum springers, i harness/contain there energy with heavy pellets, just seems like manufacturers need to take a good look at their construction and materials, but what do I know

  15. i have so many thought on this subject, i have an hw45 in .20 cal pistol and sometimes when i shoot beeman laser pellets 10.96 gr. i hear quite a loud bang (they don’t fit that good in my gun). also when i try heavy pellets like beemans silver arrow 17.5gr. which fit very tight there is no big bang and the pellets hit very hard even with being slowed downed somewhat. so is not fit more important based on the skirt diameter and design of the pellet ( rnd, flat, pointed etc.)

    up here in canada ah!

  16. springs….waves… thats what springs do. that wave helps to disapate energy. god forbid a shock wave doesn’t happen, otherwise, all the energy would focus and accumulate at one end/tip of the spring and heat, deform, explode (fracture/break). imagine you and your friend are holding a spring at opposite ends, and you both can let go at the same time, the spring would compress, the energy would accumulate in the exact center of the spring, an equal shock wave is sent back in the direction of you and your friend, and the process continues until all energy is disapated. if that shock wave doens’t happen, and your spring isn’t made of some unearthly material, its going to heat, deform, or break (fracture) in the center.
    think about it, thats why we use springs, because they are cheap, and unleash and disapate energy well.
    you could easily be using a cocking lever to compress air, of course thats what a pnuematic gun is, but you don’t see any single stroke pnuematics that can produce 1000+fps velocities, and if you do can you imagine the price. the stroke lengh on that would have to be lengthy or the force to cock it would be too great, or it would have to be a prechared air rifle and your single stroke would have to replenish the air pressure lost on the preceding shot.
    springs are a cheaper, easily maintainable way, of getting the desired result. no one like cocking a pnuematic 7-10 times, or pumping a pre-charged gun up hundreds of times. with a springer, its one cock, and you are ready.

  17. also, that vibration you feel in the stock of the gun of your springer is more energy disapation, along with why you need a scope stop to keep your scope from moving backward as the gun lurches forward.

  18. hello canada,

    skirt fit is always important, for springer, co2, pnuematic, pre-charge, etc. pellet design is important for what you are shooting at or hoping to accomplish.

    USA here

  19. dave,

    I would assume so, because then you would have a medium (rubber) of absorption, but keep in mind, once you do that, you change the effectiveness/nature of your original spring. it may have lost some of its springy-ness do to the new medium, the weight that new medium excerpts on the coils, etc. never try to alter your springs, their nature is already perfect, you just have to harness their energy, and allow them to do what they do naturally. when yu get in their way, you limit their effectiveness. its almost like bb’s examples on how to shot a springer. when you hold it too tight, you groups open up, because your gun can’t disapate its energy in a nature way (its recoil), because you are contraining it. if you hold it lightly, energy disapates naturally, more effectively, and less violent.

  20. remember the character “Tim the Tool Man Taylor” who was always lusting after more power,…”and the trouble it got him into”. thats where we are with magnum springers now. alot people always question, “why more power” if you can’t get accuracy once you go super-sonic. their point is extremely valid. but I say “yeah to more power” if i can bring velocity down with pellet weight, and unload extreme energy. these magnums are newer and newer, and are still flushing out design issues (stronger seal, stronger piston, spring, etc.). i think mainspring issues, especially within a particular model are evidence of this. if you are sane, you would never put a 5.7L corvette engine in a pinto chasis, and expect it handle, corner, be as reliable, etc., like an actual corvette. just keep your pinto, or buy a camaro/firebird (poor man’s corvette).

  21. i know…shooting a springer is weird.
    using all other power plants i feel like i’m one with the gun. i hold them tight, and feel like i’m part of the action, that i am controlling the shot.
    with springers, because of the light grip i feel like a spectator, and just a trigger squeezer. but i love their power, easy of use and cocking, and their accuracy once you learn the technique for your gun.
    its a trade-off.

  22. Everybody,

    Just a word about LESS power. The Brits have to stay under 12 foot-pounds, for the most part, so I’d like to hear from them. A 1914 BSA that produces 10 foot pounds is different than a modern TX200 that produces 12. The older gun is overbuilt and underpowered, while the moden gun is destroked to stay under 12 foot pounds.

    It’s tempting to say the lower-powered airguns do better and last longer, but I would sure like to hear from shooters who use them all the time to know if what we believe is true.


  23. B.B. (This is related to a conversation in yesterdays blog posting)
    I realize that there are better guns on the market for accuracy and good looks besides the Gamo PX107, but the two that you mentioned are way out of my price range. The PX107 is the only pistol I could find in its price range that looked modern, was semi-auto, and had a rifled barrel. I figured the rifled steel barrel would improve its accuracy above the competition in its price range (less than $75). Let me know if I am wrong on that.
    Here is the list of guns again, to keep you from looking at yesterday’s post, along with their respective ratings. I rated them 1-5 by looks, rated FPS, price, and accuracy (giving the rifled barrel of the Gamo a 1, and all the others a two.) I added all the scores, and here is the tally:
    Gamo PX107 – 8
    Magnum Research Baby Desert Eagle – 8
    Crosman C11 – 9
    Crosman Pro77 – 14
    Walther CP99 Compact – 14

    If you have suggestions WITHIN THAT PRICE RANGE, I would very much like to hear them. Thanks

  24. yeah, some sort of tar material would be better. there is no way you could adhere a harder rubber material to the springs without it chaffing, flaking,…i guess i could just say wearing very quicking within the powerplant. you would be left with alot a powdery rubbery residue. tar is more liquidy

  25. You know, the Cardew experiment does have a bit of a problem – by operating the rifle in a nitrogen atmosphere, they changed the working fluid. Yes, I know that air is mostly nitrogen anyway, but not completely. Frankly, I don’t know enough about the physical properties of these gases to determine the degree to which this will skew the results… but it almost certainly will have some effect.

    On a completely different subject, Pyramid sent me several packs of .177 pellets when I ordered .22’s. I emailed them about the mistake, but got no satisfactory response. So here’s a tip – CALL THEM. The girl who I spoke to was as helpful as could be, and she is now shipping me
    the proper pellets – AND she told me that I could keep the .177’s! Needless to say, I’m tickled – and pyramidair just made my list of favorite vendors….

    Now, if they’d ONLY ship airguns to NJ…. even if I’d have to show them my FID card…

  26. Anony – I have actually spent the last week revising and reconsidering that list. After I discussed rifled barrels with myself,
    I went back through the pistols listed on PyramydAir and a few other competitors sites to make sure
    I had a complete list. I am no leaning more toward the 1088. It still looks pretty cool, though not as cool as the PX107,
    but it too has a rifled barrel. The thing that made me swing toward the Crosman is that it can shoot pellets, and it costs $40
    less than the PX when you take the cost of the extra mags into account. So, B.B. what do you think of the Crosman 1088?
    Another fine choice for the price range?

  27. I need to buy a pellet rifle to kill muskrats. I think I have decided on either the RWS 48(.177 1100fps) or the RWS 350 mag (.22 900fps). I need the one with more knock down power, and the one thats more likely to kill even if I accidentally don’t hit a kill zone. which one should I get? Is there a less expensive rifle to complete the task?

  28. muskrat killer-there is a lot to take into consideration…are you shooting them from your property, when your shots will be short, or are you going out and shooting them, where you will need a longer range gun? a .22 caliber i usually the more desired for killing with a larger kill zone(not perfect shots), but you can most likely use one that shoots 200 fps slower than the 350 if your going to shoot close range. if you want an effective gun for ou to 30 yrds and very affordable at the same time, crosman makes break barrel .22 cal guns for very cheap(the quest in .22 is around $120 i think).

  29. B.B. – Neither the 1008 or the P23 meet my “looks” criteria. It is a subjective thing. I prefer the modern look of a Walther P99 over the conventional look of a Colt 1911. The P23 only sing-shoots pellets also.

    Now, I have a follow-up question. I am going to bulk-buy some Crosman Premier Dome pellets, but I don’t know whether to go light or heavy. I am also going to be buying a Crosman 1077. Do you think these guns will be more accurate with 7.9g pellets or 10.5g pellets?

  30. jandj,

    Hold off on that pellet buy! You want wadcutters for all these guns that have a circular clip. There is a pellet length issue. Crosman Supermatch wadcutters are great. So are Gamo Match.

    Definitely DO NOT get the 10.5s. they will be too long to function in your gun.


  31. Ahh, thanks for the heads-up on that one. Gamo Match 7.5’s it is. Here is another question for you since I am asking. Do the CO2 cartidges have a shelf-life? If I buy some then don’t use them for a while, will they slowly leak out like a balloon?

  32. jandj,

    No shelf life I am aware of for the modern ones. I’m still working on a box of 500 bought back in the early ’90s.

    The old Crosman powerlets with bottlecap tops did leak out – often before you got them in a gun. But the modern ones made by Crosman are stable.


  33. Dear Mr. Pelletier. Can you suggest someone who could do a first class tune up of a RWS 46, I have a Williams target rear and a Lyman 17 A front on it. It is great feeling gun, but from all the verbage on your site I seldome see it mentioned. I have been alternatly told it’s a great underlever and a really poor gun for accuracy. Please comment.

  34. RWS Diana 46,

    Who said the 46 is inaccurate? It’s nothing of the kind. It’s very accurate with the right pellets.

    I don’t know any reliable person to tune your 46. Ken Reeves has apparently stopped tuning and he was the best Diana man I knew.


  35. hi bb
    youve said in the past that underlevers will be eisier to shoot than breakbarells. i guess there are less vibrations and a fixed barell helps increace acuracy. this beeing said would you recomend the HW 57 over the HW 50? im looking to get started in field target as you probly know from my previos posts. also whats the highest power scope i could mount on a HW 57 without interfering with the loading port? also what kind of laoding port is on the rifle? thank you so much for you help and expert advice on the topic
    Nate in MASS

  36. nate,

    The 57 has a sliding compression chamber that reveals the entire breech.

    With high mounts you should be able to get away with a 50mm scope.

    Rather than not letting your scope overhang the loading port, which limits you to 12 power probably, why not learn to load with a larger scope in place? That way you could go all the way to 32 power.


  37. B.B., any increased accuracy using pellets with skirts that are ribbed? i see the majority of pellets have smooth skirts, and the pellets you usually test guns with have smoothed skirts, but i’m curious as to whether any knows or has experienced more positive accuracy or less accuracy using ribbed skirts. thanks.

  38. Ribbed skirt,

    I guess I need to address this to everyone, because a lot of people have asked the same thing. As far as I know, there is no difference between ribbed and smooth skirts, as far as accuracy goes. And there are only a few pellets that come both ways, so testing is a problem.


  39. Could anyone tell me about double loading pellets? (DLing: putting one pellet in as usual, then putting another one behind it. Firing two pellets at once.)

    I heard about this on the most reliable source, the internet, so I figure it has to be a good idea. But seriously, by DL pellets in a break barrel rifle could I damage my gun?

    Would it just be like firing a heavy pellet? Two 7.9s back-to-back would be 15.8. Might not be great for the spring.

    Or could this damage the rifling?

    I read about it in context of hunting. Apparently a pellet that would normally over penetrate would instead, with two pellets, transfer all of its energy (with one enlarged or two wound tracks).
    Sounds like a good deal to me…

    Too good to be true? Tell me.


  40. DLer,

    just my opinion, but why would you consider double loading? why would you do something that most airgun manuals say “do not do”? just use one 10gr-16gr pellet, a hollow point, or a wadcutter and improve your accuracy and the “kill zone” characteristics of your prey. just cause you can do something, doesn’t mean you should do it.

  41. Zach, by your pellet weights i’m assuming you have a .177 springer, therefore, you are taking small game. if you need two pellets to get the job done, may i recommend a shotgun…

  42. just a comment on less power and small game hunting i have an hw80 in .22 cal detuned to 500fps for us non f.a.c. shooters here in canada this rifle @ the range i belong too will shoot cleanly though 3/8 plywood @ 20 yds. and will kill rabbits @ 30 yds. with ease. pellet choice is of high importance i always use beeman or jsb pellets for their high quality (lead content not alloys in these other high vel. light pellets). because even with velocities of only 500fps you can get good expandsion of pellets giving you the wound channel you are looking for.

  43. i use fts,silver arrow, silver ace, kodiak in .177,.20, .22
    not the crow magnum in .22 yet.they are all very accurate especially the field target special.i have also tried silver bears and lasers, i find these to light especially in my hw45 pistol which i seem to get detonations because of the poor fit is this correct.

  44. @Nate in MASS


    I’ve got an HW57, and mine has a pop-up breach. This means you will be needing a shortish scope to allow easy loading. They are great guns. Nice and light and very accurate.



  45. excellent, excellent, excellent info Mr BB.

    methinkest that is you are getting more detonations with smaller pellets because the shock wave of super heated air is going around the pellet skirt and lifting lube off the barrel walls. The pellet moves allowing the detonation to behind rather then the side or front of it. This could account for detonations that occur even after the gent disasembled then cleaned and reassembled and shot. The lack of O2 in the nitrogen shots does prove detonations they figured w/o o2 there is no detonation. Also realise, that ghraphit IS pure carbon that highly powdered, and highly powdered flamables can be exploded, (see fueled arir devices/grain silo explosions), as we ae painfully aware of.

    If you put wd40 on a piece of char cloth let it dry and put it in a firepiston, you can blow the end of the firepiston off, or imbed the piston in the ceiling or brainpan. Now look at how much you put in a firepiston. Darn little actually. The lubes used in a firepiston are vaseline, bacon fat, lard, lip gloss, chapstick. And as hot as they get they don’t explode. But add WD40 and you or others can be hurt or blinded. I still haven’t gotten mine to work, and will be char cloth today to try it out if time permits. I want to have a functionintg one by newyyears if at all possible. BB I have learned so much here, on related and non related topics, again, thanks for blogging

    Sparkie- LI NY Land of “Everybody Loves Raymond”-burb to metropolis

  46. A theory, that is all it is bb, that’s all it is,

    meanwhile I found a shop here on LI, that specializes airguns. They have a real nice video for newbies like me, on shooting stances I can forward that if you like (for others, I sure you are very past it). I remember the concepts from summer camp. In january I will pay them a visit and peruse their wares. Currently I will just drool away on pyramids site.


  47. This is very interesting, even if I am coming to the discussion late.

    As for the nitrogen bag experiment to prove dieseling, I have to point out a minor flaw. Dieseling may not be the only difference between the nitrogen firing and the shots taken with air. Firing in a pure nitrogen environment may also lead to lower speeds, as nitrogen may not be able to expand as rapidly as a normal air mixture.

    This experiment should be recreated with some alternate non-reactive gases to prov the methodology. I have a feeling that performing a similar experiment, with air, and with nitrogen, and with CO2, and with helium, each gas would yield different speed ranges.

    This may have been done already, but I have not read the book. Any thoughts on this one?

  48. I recently bought a 350 Magnum .22. Have only fired around 25 rounds but oif those two jammed in the barrel and the gun made a hell of a bang. recocked and fired again and it fired normally and the original pellet came out fine. Then a few shotys later it did it again.

    Also whilst for the most part it shot accurately it threw a couple real low as in 6 inches at 15 yards.

    Pellet is as recommended by dealer and 15 g

    and thoughts?

  49. Beezie,

    Something fundamental is wrong here. Either you are not loading the pellet flush with the breech or you are using the wrong caliber pellet (a .20 in a .22) or your gun is faulty. A 350 Magnum should never stick a pellet halfway up the barrel.

    By shooting it out, you dry-fired your rifle. Don't do that again. Get a cleaning rod and run the pellet out with that.

    Check what I've mentioned and possibly think about returning this rifle to the dealer.


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