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Breakbarrels, sidelevers and underlevers Advantages and disadvantages

by B.B. Pelletier

Merry Christmas!

Today’s post is a light and easy one for me. It addresses a question from reader Stabbs about the good and bad points of the three types of spring-piston cocking mechanisms.

Breakbarrels – the good points
Breakbarrels are the most common type of spring-piston air gun. They use the barrel as a lever to cock the powerful mainspring. Because the breech is exposed when they break open, they are the easiest of all airguns to load – both rifle and pistol. They can also be lighter weight than the underlever or sidelever guns because they don’t need a separate cocking mechanism. When it comes time to take them apart, breakbarrels are simpler mechanisms, so they’re easier to repair, though they do vary in complexity by brand and model. And, finally, a breakbarrel is quite easy to clean because of the good access to the barrel.

Breakbarrels – the bad points
Breakbarrels always require the most technique to shoot accurately. They are hold-sensitive, and although this differs by model, I can say universally that all breakbarrels are more difficult to shoot accurately than any sidelever or underlever. Breakbarrels usually have barrel “droop,” which means the barrel points downward. Used with open sight, this hardly matters, as both the front and rear sights are mounted on the barrel, but when you scope the gun it becomes a problem. Also, when selecting a scope, you have to be careful that the scope isn’t so long that it interferes with the barrel being broken open.

Breakbarrels – some interesting things
Some new shooters seem driven to experiment with their breakbarrel by pulling the trigger when the barrel is broken open. If the gun shoots (a lot of them won’t), the barrel snaps shut, bending the barrel upwards and often cracking the stock. This is guaranteed to bend the barrel of the rifle or pistol every time, so be warned. And, dealers have learned to spot this kind of abuse, so they usually don’t honor the warranty when they see this.

Some shooters avoid breakbarrels because they believe the barrel has to bend over time by cocking the rifle. That’s not true. They are 100 year-old breakbarrels that are just as straight as the day they were made. Barrels can easily be bent through abuse, but they never bend in normal use.

Sidelevers – the good points
Sidelevers have a separate cocking lever on the side of the gun. They have a fixed barrel that many feel is more accurate than a breakbarrel. Although it isn’t, it’s easier to shoot a sidelever more accurately because they’re less sensitive to handling. So I guess it’s true that a sidelever will be more accurate than a breakbarrel in most shooters’ hands. Just watch out for the man who has learned the right technique with his breakbarrel! Sidelevers can also accept longer scopes because the barrel doesn’t tip up and get in the way.

Sidelevers – the bad points
Sidelevers tend to torque (twist) to the right when they shoot. The sidelever unbalances them to the right (because the lever is on the right side for right-handed shooters) anyway, and when the mainspring decompresses, it twists violently in that direction. The also have sliding compression chambers that can amputate fingertips if the sear releases while the gun is being loaded. That was a big problem with the original Chinese TS45 sidelever before the design was revised. Diana sidelevers have always had those safety features, so they’re not a danger. Sidelevers can droop as much as breakbarrels, though the tendency is not to. And, finally, sidelevers have to include the weight of the extra lever, so they’re usually heavier than breakbarrels, if the breakbarrels were made to be light.

Underlevers – the good points
Underlevers tend to be the easiest of all spring guns to shoot accurately. The Whiscombe, TX200 Mk III and both the HW77 and HW97 are underlevers with legendary accuracy. Unlike sidelevers, underlevers have no pronounced torque when they shoot. That’s because the extra weight of the rifle hangs straight below the barrel as a counterweight. But, underlevers have the same sliding compression chamber with the same safety features as sidelevers, so long scopes are easier to mount.

Underlevers – the bad points
The sliding compression chamber is a safety risk, though all underlevers sold in the U.S. today have the proper safety features to prevent accidents. But older rifles such as the Chinese B3 are very accident prone. Like sidelevers, underlevers are heavier because of the lever and attaching mechanisms. Underlevers are particularly difficult to mount slings because the underlever tends to pop away under pressure.

Well, there you are. Perhaps you readers can add to these lists of good and bad points for me?

Merry Christmas.

43 thoughts on “Breakbarrels, sidelevers and underlevers Advantages and disadvantages”

  1. Thank you for the article. You touched on some things I never thought of. I’ve only owned two springers in the past. One, a cheap chinese side cocker. Stock chopped out of a 2×6, floppy rear sight. You know the type. The other a youth model CZ break barrel.
    I have my eye on a Diana 46ST in .22. It’s a beautiful little rifle. Anyway, keep up the writing. Your experience is very helpful.

  2. Since you asked – breakbarrels (especially the cheaper ones) can develop slop in their pivot mechanism, giving an inconsistent lock-up and, in extreme cases, shifting around during the firing cycle. This particularly plays havok with a scope.

    The only gun I ever had this happen on was a Chinese-built B19. Drove me nuts for months, until I replaced the pivot bushing and bolt. That cured it.

  3. Vince,

    No, brealkbarrels usually do have droop. It’s caused by the angle the breech is cut on and the height of the breech seal. Airgun makers don’t care about droop because it doesn’t matter to them. The front and rear sight are on the barrel so there is no problem. But when you scope one, the problem becomes all too evident.

    The amount the breech seal tips the barrel forward affects the alignment. Even if the difference is less than a thousandth of an inch at the breech, by the time it reaches the muzzle, it’s magnified greatly, and downrange it becomes several inches.

    As for the pivot bolt looseness, I have been encountering that a lot more recently. It isn’t supposed to happen. The barrel should remain in any position, once the gun is cocked.


  4. Merry Christmas BB, and Company.

    Well only a few things compare to the joy of a young boy opening his first BB gun on Christmas. Its like watching a tropical sunset, or light snow falling; or seeing that buck prancing by your stand. Just one of the many joys I was able to experience on this glorious day.

    God bless everyone and their families on a wonderfull Christmas day.

    JoeG from Jersey

  5. B.B.

    I just want to wish you a merry Christmas and I hope you enjoy this day with your family and friends.

    I want to thank you once again for the great gifts you give us every day – your airgun advice!

    Thanks a lot

  6. Hi BB,

    Merry Christmas to you and your readers!

    I find the breakbarrels more difficult to cock and load in confined spaces, or when sneaking around in the prone position.

    When I’m hunting pigoens and starlings out of the car around farms and grain elevators my sidelever is much easier to cock and load, even though it’s a bigger and heavier gun. You just stick the barrel out the window, tilt the gun so the sidelever clears the steering wheel, and you’re in business.

    Loading the breakbarrel while sitting in a small car is much more difficult.


  7. Hey B.B.
    I’ve read a lot of your blogs and whatnot, and they have really helped a beginner like me. I eventually bought the Gamo Shadow Combo, and it’s quiet a blast. My 2 questions are, and sorry if it’s a little bit offtopic but…:
    1) What are some reccomended pellets for the shadow. I live in WA and the variety they have here are Crosman Premier HP, RWS superpoint extra, rws diabolo basic, and gamo pro-mag.
    2) What would be a recomended way to look through the fiberoptic sights on the shadow? I just line them up and use the red front sight to cover an area to aim at. Are there any more better ways to aim through?


  8. Pat,

    Those Premier hollowpoints should be pretty good as long as you use the correct artillery hold technique. It has to be deal-calm and allow the gun to recoil as much as it wants to.

    As for the sights, yes, just cover the target with the red dot and you should be on.


  9. Merry Christmas to you BB, and Merry Christmas to all of you out there. It’s snowing hard here in the Denver area today. And piling up fast (for around here). There’s a dedicated airgunner in BB. Writing answers on Christmas Day. Thanks for your wit and wisdom, BB and all the rest! I’d say my favorite cheap plinker is either my B3 (Cummins Tools for 20$) that I tuned, or my Beeman Siver Bear 1783. The Beeman is made for a child, but since I don’t usually use the sights with it, that doesn’t bother me. When I do use the included scope, it seems pretty darn consistent and accurate. Even with its broken spring guide. Well, back to moving snow around… Merry Christmas everyone!!


  10. MERRY CHRISTMAS, BB. We’re fixing up around here for the annual Xmas party. No snow, because we’re on Maui, but still, I’ve heated the indoor swimming pool to comfortable proportions and we’re expecting about 100 or so friends, merry makers, and people who have no place to be on Christmas day. Doubtless the day will include a bit of airgunning in the yard as well, with a big game hunt for animal crackers. My regards and appreciation to you and all posters hereabouts, for the great stream of information and insight you all share.

    –Joe B.

  11. B.B.

    No rest for the wicked, eh? Just kidding of course. Thanks for blogging right through Christmas, and with such an intriguing article about a topic of particular interest to me.

    Before I get into that, thanks for answering my question yesterday about scopes. The fact that firearms scopes can be used on airguns is news to me. I thought they tended to break on spring guns because of the two-way recoil. Can I assume that airgun scopes are okay with firearms? I’m thinking of getting a Savage 10
    FP LE in .223, so the recoil shouldn’t be that great.

    Today’s blog about the torque for sidelevers is also news to me and a little disturbing. This looks in a fair way to dislodge the BAM B30 from the top of my purchase list where it has recently clambered its way. Can I assume that torque increases with the power of the gun? I don’t notice this effect at all with the IZH 61, but that is just about the lowest powered rifle that I have come across. With its advertised 1100 fps in .177, the B30 might be a different story. Would tuning care of this problem if it appears? I know that Charlie Da Tuna talks about reducing torque as one of the benefits of his tuning job. Thanks.


  12. BB. great blog as usual!!I CANT BELIEVE YOU ARE WORKING on XMAS DAY!!Thanks for your responce to my feedback on Gamo Recon! A REALLY fun little gun!! To my total joy today,, a waiting line to shoot it!! A great xmas!! I will do serious reveiw for P.A.! It is really VERY ACCURATE!!!As I said before it is very quiet,at about 500 fps,,Bitc#@$ neighbors dont complain!! MY BIG NEWS TO ALL, how about 850+ fps even quieter??? RECIPE: Buy one Cros. G1 Extreme 177 break brl. Clean brl. like bb. says to do,,VERY NASTY DIRTY from factory!! After scope set up & break in I consider 500 shots min.Now comes the fun mod. part!! Remove muzzle break,note where allen screws are in relation to end of brl. You can re attatch break to brl. so screws are JUST in front of end of brl. creating a large CHAMBER in front of brl. symaler to that of a Tallon ss..! This helps muzzle report ALOT!, but it gets better!! You can put elc. tape over end of break & poke small hole in center of it & muzzle noise becomes NON_EXISTANT!! After about 20shots acuracy will return!! As my son said the tape is kinda GHETTO! So I put the break in a jig on drill press & centerd w/ bit & carefully w/ toothpick applied epoxy to parymader of exit hole,re drilled hole just slightly larger than 177, re crowned w/cs. bit & PRESTO!! This gun now has ZERO MUZZLE blast!!!SUPER QUIET!! Now if I can just shut up that main spring!! BB. where can I buy that black tar grease?? Sorry to Hog the blog! Tim in S.C. AKA Drag. Slay.

  13. BB and everyone,

    Merry Christmas to all.

    BB, thanks for the Christmas present, a blog on Christmas day!

    Lot’s of great info. Knowing others are thinking about airgunning today makes me feel less guilty.

    Happy New Year which means great and happy airgunning!

    Al Pellet

  14. Must clarify before A.T.F.comes to get me!! My little mods. listed above incude NO BAFFLES!! Note , MUZZLE BREAK!! Those in the know, know that springers produce very little muzzle report anyway,as air is almost expended as pellet exits brl. I played w/ this mod after shooting a Whisper at local gun shop! Must say tho my G-1 mod is even quieter than Gamo Whisper!! Off topic ,, alot of you ,,like me, want gas springs to be sold as a DYI Option!!!!!Pyramid it is great that you are BUILDING custom guns w/ gas springs now!! To the rest of you guys out there that I read your blogs from,,,,IT IS ONLY AMATTER OF TIME!!!I know you guys will post as to where we can buy gas spring only!!! Sorry P.A. You will always BE THE BEST for me!! Drag. Slay.

  15. Johnny,

    If you are referring to the RWS Diana sidelevers, then yes, they do produce more energy for less cocking effort. But that’s just a single design that has excellent geometry. I don’t think it’s due to them being sidelevers as much as the excellent linkage Diana designed.

    The Chinese company, Brolin, went Diana one better by making the sidelever extend another 4 inches to give even better leverage, when they copied the 48.


  16. Matt61,

    Absolutely no problem using airgun scopes on any forearm, up to .50 BMG. Airgun scopes are made better than most firearm scopes and are every bit as rugged. That said, most firearm scopes are braced for airgun recoil these days. Manufactures learned that doing that improved their entire line.

    The only companies to watch are the cheaper Chinese makers like Red Star and a few others.

    Yes the torque effect increases with power. And even in a Diana 48 is isn’t something awful. But it is noticeable. Ken Reeves used to put a thin roller bearing in his guns to absorb the torque. But don’t make too much of it. It’s simply a phenomenon that you can observe. It doesn’t hurt the accuracy of the guns.


  17. Hey B.B.

    What do you do for fun on your day off?? (;>)

    This blog and your (extremely) timely replies have really helped me go from an old gun nut who hadn’t really shot much in 20 years to a well informed airgun nut in just two weeks!

    I finally took the plunge and ordered a Diana 46, CP 3-9×40 AO illuminated scope, Accushot 1 piece high mount, Plano case, and Crow Mag, Premier Domed, and JSB Diabolo Jumbo Match pellets. Not quite in time for Xmas, but I think I got it right, that’s more important…jeez I just love the internet sometimes! It would have taken me five years to learn all this stuff 20 years ago.

    Thanks and Happy New Year!


  18. Hey BB

    It’s pat again, and mighty thanks for the help. I have one more small question. I bought the Shadow Combo at Big 5 for 140 bucks, after the guy had reduced it by 10 dollars. It was an open box(display box, etc) sale, and I’m kinda suspicious if it was really used. The guy said it wasn’t, but people these days aren’t the most trustful. Can you tell me any early characteristics of the Shadow when bought new, as opposed to used?


  19. Jay,

    My days off are filled with shooting firearms and reloading for them. It’s a busman’s holiday, but I love shooting and I also write the occasional firearm article for Shotgun News.

    Your shooting past is very familiar. I hear from lots of firearm shooter who gave it up because it was too much trouble. With airguns they can shoot again and they don’t have to suffer any loss of fun.

    Enjoy your new rifle, and don’t forget to tell us about it.


  20. Pat,

    Look for cocking marks around the base block, which is the block that holds the barrel. That area gets scraped shiny pretty quick.

    If the gun makes cocking noises it’s probably new. They diminish as it breaks in.

    If someone tried it for a few shots (less than 100) it would be almost impossible to detect whether the gun was new or used.


  21. Merry belated Christmas & Happy New Year!!!

    Thanks BB for the awesome post. I am getting ready to make a purchase from PA within the next week or 2, and this article has been EXTREMELY helpful on narrowing the field.

    A couple of questions to go along with this- Does mounting a bipod to the barrel of a break-barrel reduce the “droop”? Can a bipod be mounted to an underlever?

    Thanks BB!!!

  22. Stabbs,

    A bipod changes the vibration nodes of anything it is attached to, so that will affect accuracy, but nobody can say how until they shoot it. The bipod will not decrease barrel droop.

    Some bipods can clamp to the underlevers, but they can also get in the way of cocking when the lever is pulled down and back. It’s an iffy thing.


  23. Hey BB, thanks for the reply. It appears that the block wasn’t really scratched “shiny.” I just have one really quick question about the accuracy of the Shadow. I shot a smaller than dime sized group at 10m with the RWS Diablo Basic, and my Q is: would the supposedly “better” and more expensive match RWS, Hobby, be more accurate than even the basic version?


  24. Pat,

    Maybe not. The best pellet for a particular airgun isn’t always the most expensive one. Sometimes it’s a cheapie, though usually it’s a proven brand. However, you won’t know until you try.

    I would try the new Air Arms diabolos. They are really made by JSB and are excellent domed pellets.


  25. i recently bought a bsa 4×32 rifle scope for my crosman storm xt.. i get tight groups for a little bit and then pellets start wondering off again. getting fustrated…….

  26. Wandering groups,

    Where is the vertical adjustment set? Is it near the top? If so, your erector tube is floating and the scope can’t hold zero.

    Here’s how to test. Run the elevation down 100 clicks and shoot some groups. They will be way below the aim point, but see if they still wander. If not, it was the erector tube and you need an adjustable scope mount.


  27. Wandering groups,

    The erector tube holds the crosshairs and moves inside the main tube when they are adjusted. It has return springs on the back side of both adjustment knobs, to push the tube back when you loosen the adjustment (up and to the right loosen the adjustment knobs).

    I recommend that you read the six articles I’ve written about scopes for Pyramyd AIR. They are here:



  28. hey there bb
    love your blogs you sound pretty informed what a great job you must have. i have two older guns a sheridan blue streak circa 1982 in mint condition before benji got involved and an old 1968 or so crossman model 140 and am now looking to buy the super streak seems like a heckuva lot of gun for 300 bones well not looking to buy am GOING to buy and also drop a grt-III trig mod in right away i’m going to get into the shooting club in my neck of the woods any other mods i should consider right away can’t afford to drop 600 bones for now trying to get the most bang for my dollar can’t wait to here what else you have got to say about the big benji

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