What happens during a spring gun break-in? – Part 2The physical changes

by B.B. Pelletier

Part 1

Okay, yesterday’s post did not explain the physical changes that take place during the break-in of a spring piston airgun, so today I will finish the report. I assumed that all readers had followed the 13-part spring gun tuning series I finished back in August of 2006 and would be able to match the results of the break-in period with the things we did in that series. Some of you did, no doubt, but I keep forgetting that we get new readers every week, and many of them haven’t had the time to read all the blogs we have done since we began in March of 2005.

Today I will explain what happens to the physical parts of the gun. You more experienced readers can keep me straight by adding your comments.

Spring-piston technology
A spring-piston airgun is a purely mechanical machine – perhaps among the few remaining in production. It has no microprocessors and requires no electronic test system to keep it running. It works on purely mechanical energy (excluding the one Rutten rifle that’s cocked by a motor), with mechanical parts working together to produce a propulsive force.

As a society, we have forgotten what mechanical devices are like. We forget that an automobile used to have to be broken in after purchase with a process of slow driving followed by short sprints. Only after thousands of miles were on the odometer was the car loosened up enough to drive normally. There are many other examples, like leather cowboy boots, but you get the idea.

A spring piston airgun comes to you from the manufacturer full of burrs and sharp edges. Each manufacturer has different levels of finishing before the gun leaves the plant, which was the point I tried to make about the differences between guns and their break-in periods. Weihrauch rifles, for example, tend to have more burrs and sharp edges than Air Arms rifles. On the other hand, the Weihrauch HW45 spring-piston pistol (Beeman P1) comes from the factory in a very polished and ready-to-go state.

Wear-in
As the powerplant parts slide through their cycle time after time, the burrs and sharp edges wear off. You can see this when you disassemble an airgun with a few thousand shots on it. There will be shiny spots where metal-to-metal friction has worn the parts smooth. As the burrs wear down, the parts slide with less friction, which is where the cocking effort reduction comes from. It’s probably also where part of the velocity increase in the TX200 Mk III came from, but that begs a question. Why didn’t the Beeman R1 increase in velocity after the break-in? That’s because of one of those difference I talked about.

Seals can wear-in, too!
The R1 piston seal is a parachute design, the same as the TX200. But the thickness of the lip is different, as is the material from which the two seals are made. The Weihrauch seal does just about all it’s ever going to do right out of the box. The TX200 seal likes to be worn-in. It isn’t made of steel, but even a synthetic part can experience a wear-in.

The proof of the Weihrauch seal being maxed is that you can replace it with a different type of seal and get different performance from the gun using all the same parts. The old blue Beeman Laser seal, for example, had to be sized to fit the cylinder of the R1. Until is was, you couldn’t get it in. Do a good job and you got an increase of 200 f.p.s. in .177 using a lighter-weight mainspring. So the rifle cocked easier and gave 200 f.p.s. more velocity. However, if you didn’t size the laser seal correctly, the gain was marginal, if any at all. So that seal really had to fit the cylinder tight to work.


The Diana 48 seal on the left has been fired between 1,000 and 5,000 times. The pretty blue seal on the right is new. The dark seal is as close to new as you can get, except for the color from the lubricant is has absorbed. Larger seal on the bottom is a new unfitted R1 Laser seal.


This R1 Laser seal was in a rifle for over 2,000 shots. Except for discoloration from lube, it shows no wear.


This experimental R1 seal was damaged because it didn’t generate a high-pressure air cushion to retard its forward movement. It slammed into the end of the transfer port repeatedly for hundreds of shots. At the chronograph, the velocites were slower than expected. Firing was harsh. I show this to point out that airgun parts are not produced by guessing or chance. If they aren’t right, they don’t wear in – they wear out!

So Weihrauch seals don’t change when they wear in, but Air Arms seals do. And Diana seals also don’t change much as they wear in.

Triggers
Yesterday I mentioned that BSF airguns were overbuilt, but I didn’t explain what I meant. Let’s look at their triggers. The lever portions of the BSF triggers were made of numerous plates that were riveted together to act as a single solid piece of steel. Those joints where the plates were cut were rough. A new BSF gun had a horrible long hard trigger pull. But after 4,000 shots, the pull smoothed out (from metal wear) to a beautiful clean letoff. Older Gamo rifles were the same way, though not for the same reason. All their parts were punched and formed from thin sheetmetal and they were loaded with sharp edges and burrs. Horrible triggers at first, but after 3-4000 shots, not too bad.

But did you happen to notice that the two R1s Gaylord tested had slightly different velocity numbers with the same pellet? That drives some owners wild. They think their guns should all have identical performance because they are all made from identical parts. The truth is, those parts ARE NOT identical in any way. The miniscule differences caused by finishing and interaction with other slightly different parts makes each airgun unique. I think it’s wonder they are all as close as they are, given the influences of such small variations.

Now I need you readers to tell me if this was a satisfactory explanation, taking what I wrote yesterday into account. Remember, I am answering Scott298′s question about what happens during the break-in of a spring piston airgun.

47 thoughts on “What happens during a spring gun break-in? – Part 2The physical changes

  1. bb,

    this seems like a good time to ask a question about my g1 extreme. i have put 1000 shots through it, and there is still smoke in the barrel after each shot…is this normal for a break barrel? also, it seems to be making more noise when cocked/shot, so im assuming its time to put some silicone oil in it. will pellgun oil be alright, or should i buy some crosman silicon oil? one more thing…yesterday, i was getting great accuracy out of the gun, but then one time, when i was cocking the gun, it slipped off of my leg(the butt of the gun)and my arm hit the scope. is this enough to break the centerpoint? i cant seem to hit much now, but im pretty sure when i went back to shoot again, i was making some mistakes, so im not sure if the scope is alright. thanks for your help.

    Dave


  2. Dave,

    The smoke is normal for a breakbarrel. Adding oil now will prolong it and make it worse.

    Pellgunoil is not the stuff to use. You want pure silicone chamber oil.

    You might put some spring cylinder oil (10 drops) on the mainspring at this time. That might smooth the action a bit, though I doubt it. Still, it won’t hurt the rifle.

    As for what happened when the gun slipped, as long as the scope hit your arm I think you are all right. CenterPoint scopes are made from a machined billet rather than drawn tubing, so they are extra-rugged. The scope might break your arm, but I doubt your arm will break the scope.

    But I wouldn’t be surprised if your zero wasn’t ruined. I would re-zero the gun.

    B.B.


  3. B.B.

    I own a beeman R9, the recoil is too much for me so i would like to leave it cocked for a week to see if that lowers the power and make the gun less buzzy with less recoil. i don’t have the money for a tune up. do you think my method will work?

    Thank You
    Doug.


  4. Doug,

    Have you tried relaxing your hold? I too have an R9, but the recoil is only an issue if I hold it too tight! Using a relaxed hold really helps a lot with this rifle.

    -tom


  5. Doug,

    What you are thinking of is not good. When the spring fails it will cant, leaving you with a badly vibrating air rifle.

    And a week won’t do it. It takes a month to reduce power 5 percent. And it doesn’t reduce the cocking effort – just the power.

    B.B.


  6. thank you for the response on the 24″ barrel question i’m wondering if you can give me a brief answer on why you get so much velocity just from a barrel increase and will this use more co2 per shoot.

    thx.
    up here in canda eh!


  7. Why do you get more velocity with a longer barrel? Well, when you push a car, why does it go faster and faster the longer you push? That’s right – constant acceleration. Same thing in airgun barrels for pneumatic and gas guns, because they do not pressure equalize until long after the pellet leaves the muzzle. Hence the “bang.”

    Will it use more gas? With a CO2 valve I doubt it. With certain tuned pneumatic valves, probably so because the valve remains under backpressure longer – holding it open longer.

    B.B.


  8. B.B.–Scott298–report about my rws 350 and umarex. They replaced the mainspring and the mainspring tube. I asked them to run thru a chronograph -they shot rws super points 8.2gr and for a velocity thry reportred a high of 1094fps and a low of 1075fps. With a little bit of whining-and the fact that I was posting my results on this blog, they offered to throw in 4 tins of pellets-not spceified-chamber lube, spring cylinder oil and the needle. Since I have about 20 tins of heavy weight pellets and had already bought a cleaning kit with the listed supplies i felt there offer was moot. I did convince them to send the gun back 2 day express. I recieved my gun this morning around 10am EST along with a tin of wad cutter pellets. I took the gun to my home made range-along with my Cabela’s portable shooting bench and ran around 100 rounds thru it. With a few minor touches the scope was zeroed and the gun cocked smooth as silk-at 25 yards Iwas shooting 5 shot groups that could be covered by a penny-no complaints-and to top it off it was wrapped better than it was from the factory–shoot straight -Scott


  9. B.B.,

    I’ve read your entries about the Sheridan Blue Streak and bought a Benjamin 392 along with a Williams peep sight from Pyramid. It’s a nifty little rifle with some power and fun to shoot. Only complaint is a blister on my thumb from pumping it. It makes very nice 1″ or smaller groups at 20 yards with the peep sight. Do they make smaller apertures for the Williams sights?

    I spent some time tinkering with my Diana 46 and 48 replacing both springs with Maccari spring kits. Due to some mishap on my part, I had to take the 46 back apart to replace the piston seal. I had only shot it a few times but the new spring was already starting to get a slight bend. I’m guessing this is sort of normal even though it has the spring guides on both ends. The center has to go somewhere when it’s compressed right? Is this normal as a spring breaks in?

    Shawn



  10. B.B.,
    The two break-in blogs, along with the tuning series you ran way back, helped my understanding a lot. But I am confused about lube for the spring/spring chamber, in particular for a B40. I’ve got some of the heavy tar, and clear tar, and moly. The spring chamber oil mentioned yesterday is a new one on me. The B40 had a light oil on the spring, and the spring seemed kind of dirty. I think the heavy tar is to dampen a noisey spring, and the B40 is relatively quiet. But what about the clear tar and the moly and the spring chamber oil. I guess they each have their appropriate application and a experienced tuner would know. Can you help clarify?
    Thanks,
    Pestbgone



  11. Scott298,

    So you have your rifle back and it is good. That’s great. So everyone should know that Umarex USA did a good job and restored your rifle to it’s iormer glory.

    Believe me, I do understand the disappointment you went though while this took place. It’s never fun to loose a friend like your best rifle.

    Good report.

    B.B.


  12. Shawn,

    A slight bend isn’t anything to worry about, but if it becomes more pronounced it will make the rifle twang with vibration. So the smoothness of the shot tells you the health of the spring.

    B.B.


  13. Pestbgone,

    Spring cylinder oil (not chamber) is just a means of oiling the mainspring. It is not as good as any of the “tars” which are all thick viscous greases that dampen vibration, as you state, but oil is the only thing you can do without disassembly. The clear tar is just a different formulation and not quite as viscous as the black.

    B.B.


  14. Pestbgone,

    When Beeman sold Mainspring Dampening Compound (what you call clear tar), it did reduce velocity a little. Then Ivan Hancock came out with a product that was black and clung to the spring almost like rubber. Tom Gaylord referred to it as black tar in an article he wrote, and Jim Maccari soon came out with a product of his own that he also called black tar.

    Jim’s product does not rob a gun of any velocity unless it is applied too thick, but shooters were used to the Beeman product doing so, so after a few years, Maccari changed the name of his product to velocity tar, to convey the idea that no velocity would be lost.

    B.B.


  15. B.B.
    OK. Now I think I understand. The B40 is easy to take apart, and not twangy, so the clear tar should probably be my first choice.
    This sport really has a rich history with certain individuals being serious standouts in the technology. I appreciate your sharing that with us.
    As always, thanks!
    Pestbgone
    P.S. I was offline for a while and just got to read your blogs about FT. Great stuff again!


  16. Am I a sicko or just an airgun nut for reading the story about that opera singer who shot himself with an air rifle and immediately wondering what gun it was? Had to have been either a pcp or a heavy duty springer.



  17. B.B.–Scott298–I havr the leapers ACCUSHOT scope with the unique zero locking and zero resetting feature, however it did not come with any instructions. Can you shed a little light on this for me as I am not sure How to set it up properly-thanks Scott298


  18. Scott298,

    Loosen the Allen screw and pull the knob out until it disengages from mthe stem. Twist it to where you want it, then reconnect it by pushing in. Lock it down with the Allen screw.

    Leapers has a picture on their site with every scope that has this feature.

    B.B.


  19. BB – I have sticky cocking arm on my 48, and sounds like Scott had good resolution with his umarex service. My 48′s cocking lever gets stuck at about 85% and I have to ‘bounce’ it to get it past the sticky part to fully cocked. I was wondering if this might dissapear with break in or if it is a sign of imminent failure? One of the other forums they mentioned a bent piston tube or something of the sorts.

    I hope I didn’t miss it, but is there anything I should do to ‘tune’ my T05 trigger (?) on my new 48?

    Last – do you have any tips for setting zero on the centerpoint scopes besides what might be in the directions?

    Thanks again, great post!
    Ozark



  20. Ozark,

    I too had the problem of a sticking cocking arm. I have taken mine apart while tuneing it and found pieces of a pellet lodged in the top of the sliding compression chamber. Never let your friends shoot your air rifle without showing them how to load the pellet all the way into the barrel. That probably wasn’t the cause of the sticking though. These rifles have numerous sharp machined edges that could use a little smoothing over. I took them off with a fine grit sandpaper or a needle file. I haven’t had any problems with it since. With some moly on all the moving joints, it cocks like butter.

    Pestbgone,

    I used velocity tar on the spring when I tuned mine. I have heavy tar as well but haven’t used it yet. The velocity tar is thick enough and makes a gooey mess if you aren’t careful. Use vinyl gloves and a short stiff bristled brush to apply it. I took a 1″ paint brush and cut the bristles down to 1/2″. Clean all the old grase and oil off the spring with your choice of solvent and wipe dry. Get very little tar on the brush and work a small area of the spring spreading it out in the process. All you need is a thin coat on the outside. It will work it’s way into the center as it’s fired later on. Greased Lightning is the best thing to remove Macarri’s tar from your clothes since it’s non solvent based and almost harmless, just messy. That being said it takes paint thinner to get off your hands completely.

    I’ve never heard of anyone using the clear tar on the spring. It’s a lot thinner than velocity tar and only used on the inner diameter of spring guides sparingly. http://www.gatewaytoairguns.com/library/all%20about%20lubricants.htm Charlie gives a short description of various lubes and how they’re used.

    Shawn


  21. Ozark,

    Shawn gave you a good answer. I would just add that there could also be an internal problem with the gun. You could fix it yourself, as he advises, or this might be the the time to try the Umarex return policy.

    B.B.



  22. RE: Air Rifle Headquarters (ARH) lubricants

    Hello All,

    On the individual ARH web pages Maccarri indicates general usage recommendations, for each of the lubricants. I’m sure the descriptions are subject to change over time as he adds/removes product, changes package size, and/or offers a “lubricant Package Deal.” Keep in mind that Maccari’s brief and sometimes mysterious product descriptions are intended for experienced/professional users.

    For example, this is the current description for clear tar: “LARGE Clear Tar – Great for compression tube OD’s, barrel pivots and all friction areas. Will do many guns. Required for sidelevers and underlevers.”

    Most if not all sidelever and underlever springers have a sliding compression tube fitted inside the action’s main tube, in order to permit loading a pellet into the fixed barrel breach. A portion the compression tube’s outside diameter (OD) is visible, because of the cut-out loading port typical to the design. Clear tar is used to lubricate the “compression tube OD” because of the visibility/staining issue associated with using black lube in this application.

    I hope this helps. If you bought some ARH lube and don’t remember the application check out the web page for that lube @ http://www.airguns.citymax.com/page/page/251484.htm

    Cheers,
    GH
    ***
    “It [a task] always takes longer than you expect, even when you take into account Hofstadter’s Law.” — Hofstadter’s Law



  23. B.B. wrote, “Now I need you readers to tell me if this was a satisfactory explanation, taking what I wrote yesterday into account…”

    Hi B.B.,

    For what it’s worth, looks like to me you could stick a fork in that and call it “Done!” ;o)

    Cheers,
    GH
    ***
    “It [a task] always takes longer than you expect, even when you take into account Hofstadter’s Law.” — Hofstadter’s Law


  24. Duct seal,

    What you referenced does not seem to be right. The duct seal I have been talking about is much too viscous to ever pass through a caulking gun tube like the one pictured.

    B.B.


  25. anonymous wrote, “…i want to confirm what Duct Seal actually is…”

    As I understand it, what you are looking for is a dense, very sticky, non-drying putty like material. It’s typically used by electricians, for sealing “raceway connections” as well as “low and high velocity ducts fabrication/assembly.”

    This so-called “duct seal” is typically packaged in 1-lb. and 5-lb. ‘bricks’ warped in plastic, to keep it from sticking to everything it touches. It’s typically gray or dark gray in color.

    Sorry, I couldn’t find or recognize the putty ‘stuff’ offered on the Geocel UK web site you provided. Doesn’t mean it’s not there somewhere.

    I looked for but couldn’t find a likely UK source, so here are a couple of randomly picked US sources with descriptions and pictures.

    http://www.hardwareworld.com/1-Duct-Seal-Compound-p5GDTTH.aspx
    http://www.electrical-supply.net/product.asp_Q_parentID_E_581_A_subCatID_E_593_A_prodID_E_2948

    I hope this helps.

    Cheers,
    GH


  26. B.B.
    I have been reading up on tuning airguns and came across a couple fairly detailed descriptions of how people have “buttoned” their pistons. No one has mentioned WHY. What benefit does this give?


  27. hi bb
    i was hoping you could convey a message to the pyramyd air staff. i think it would be a good idea if pyramyd sold 88 gram airsource in 5 or 10 packs for people who cant buy them locally and need to stock up with out spending $145 for 25 tanks.if they were reasonably priced this might help the sale of all their airsource powered guns. thanks.
    Nate in Mass


  28. GH & BB
    thanks, you have saved me time and money. I think Duct Seal is a US brand name, as the UK version seems to be called Plumbers Putty. It may not be identical, but it seems to fulfill the same role here, so i imagine it will have similar stopping power.


  29. Buttoning means to place six round bearings of low-friction material around the piston. Three at each end of the piston, separated by 120 degrees around the circumfrence of the piston.

    When the “buttons” are sized correctly, the piston cannot vibrate in the compression tube because there is no room. The piston is free to slide with less friction, which means more power can be generated.

    B.B.





  30. damn, then i seem to have a problem. Duct Seal as you know it simply isnt sold here. Yes, it can be imported from the states, but that would mean the postage would be 1000% of the cost of the Duct Seal :(



  31. B.B. – I just wanted to inform any of your readers who might be interested in buying the Umarex Beretta CX4 Storm that Umarex USA does NOT have the schematics on hand, required to repair this air gun, if such service is required (as in my case; of very low fps performance!). This is confirmed in an email received today (July 30th) from Glenn Seiter of Umarex USA.

    I would recommend that they wait (as least another week; according to Mr. Seiter) in order to buy this exciting (when it works!), new, rapid fire, 30 round air rifle.

    Always look forward to your blogs about air guns!

    Doug L.
    Vancouver Island
    Canada


  32. Doug,

    Thank you for this information, but I have to ask you – is it really essential that Umarex be set up for repairs the week you get your gun? They will be repairing this model, so the capability is coming. It just takes time with new models.

    B.B.


  33. I recently purchased an RWS 48 in .177 caliber. The rifle itself is top quality. I live in a residential neighborhood. I've only put a few pellets through this rifle because of the amount of noise it produces. It almost sounds like I am shooting a 22 rimfire.

    My question is…..how much quieter will the rifle become after break in (say a couple hundred shots)?

    If it doesn't get much quieter than most likely I will need to exchange it for either the Gamo Whisper or the Crosman NPSS. Which would you recommend more & why?


  34. Michael,

    I suspect that if you have shot your rifle since sending that comment, you already know the answer to how much quieter your gun will get. You have had a few detonations. The way to end them is to continue to shoot the rifle.

    The oil droplets in the compression chamber are being ignited by the temperature of the compressed air, much the same as a diesel engine. That will only happen a few times with an RWS Diana 48. After that, there will be the sound of a releasing spring and a piston stopping rapidly, which is nothing like a .22 rimfire.

    The rifle will not become much quieter after that point. It can be heard 50 feet away at all times–but that is true of most spring air rifles. The NPSS is quieter, but no spring air rifle is ever completely silent.

    However, the lower the power, the quieter these guns can be. A Hammerli 490 tuned by a competent airgunsmith would be almost impossible to hear 50 feet away.

    If quiet is what you need I suggest you get a much less powerful spring piston rifle, or consider the Benjamin Marauder precharged rifle, which is one of the quietest air rifle on the market. I doubt it can be heard from 35 feet.

    B.B.


  35. Michael,

    Your research found an appropriate topic for your new airgun that still needs time to break in. Although B.B. has answered your questions you may want to consider joining the active discussion among other airgunners like yourself.

    Your question was posted under an appropriate topic for your situation but the article is over 2 years old and not many airgunners check back on the current comments for an article this old.

    Please consider joining us. The current discussion among airgunners, like you, is taking place under the most recent article that B.B. has written. B.B. writes a new article everyday, Monday-Friday. Here's a link that will always take you to his most recently written article (you'll need to copy and paste the link). If you scroll down to the bottom of that article and click on comments you will join the most active dialogue in progress:

    http://www.pyramydair.com/blog/

    Look forward to seeing you there!

    kevin



  36. Am I a sicko or just an airgun nut for reading the story about that opera singer who shot himself with an air rifle and immediately wondering what gun it was? Had to have been either a pcp or a heavy duty springer.


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