by B.B. Pelletier
This is an answer to a question asked last week: “I was wondering if breakbarrel springers ever wear loose at the hinge and become inaccurate?” That’s a common question that deserves an answer.
Some history about the ancestors of modern breakbarrels
You must understand that spring-piston airguns are a more recent development. They’re just over a century old, so there’s not a lot of real history to support this answer. The earliest models were made with soft iron frames and they DID wear, as our reader suggests. One of the more popular types of breakbarrels are the Gem-type rifles, and they almost always wear loose.
On a good modern airgun, the joint compensates for wear
Coming to the recent past, breakbarrel design has been improved to the point that wear has become a non-issue. Most quality breakbarrels, such as the Beeman R1, have some kind of thrust washer to provide a lower coefficient of friction at the joint. When airgunsmiths tune a breakbarrel, one of the things they do is lubricate the thrust washers and the pivot bolt with some good heavy-duty lubricant to further reduce friction.
The pivot bolt is the fulcrum as well as the axle around which the barrel rotates when the gun is cocked. The mark of a good breakbarrel is a wide-diameter bolt to spread the cocking load as broadly as possible. They all have bolts that can be adjusted to take up any slack that might form over time.
The spring-loaded detent assures a good breech seal and barrel lockup
Besides thrust washers and thick pivot bolts, breakbarrels rely on a spring-loaded detent to maintain pressure on the breech joint when the barrel is locked up. The best detent, in my opinion, is the chisel type. It pushes the hardest because it has more travel by design than the ball bearing type that RWS and the Chinese companies use. Still, I’ve never seen an RWS (Diana) breakbarrel with a loose joint, so I guess the ball bearing works well enough.
If you DO find a loose breech joint, tighten it!
It’s the owner’s job to watch the breech joint for looseness and adjust the pivot bolt when necessary. If you grab the barrel and can wiggle it side to side between the action forks, the breech joint is loose. Consult your owner’s manual for instructions. Lacking a manual, tighten the pivot bolt until the barrel remains in any position after the gun has been cocked.
I hope this eases your minds about breakbarrel guns. They really don’t have problems with loose joints any more.
Many thanks for this interesting post. I tend to agree about good quality air-rifles not becoming loose at the hinge. I have an old Diana break-open air-rifle which is probably from their early post WWII production, which has seen plenty of use, and it shows no signs of loosening.
Since the barrel doesn’t really loosen, is there any practical reason not to replace the open sight on the near end of the barrel with an aperture sight on the receiver?
Thanks!
Denis
Denis,
The problem with Diana breakbarrels is the barrel slants downward to a large degree. They are difficult to scope for this reason.
If you can get the sights aligned, it will work, but that’s the trick.
B.B.
B.B.
Me again, I have another problem with my rifle. The pivot bolt is loose. I cannot tighten it any further as I don’t want to strip the thread. It has a second small screw that locks the pivot bolt in place and it wont allow me to turn far enough to fit this second screw in. I installed a small rubber washer and that seems to have sorted it for now but is there a professional way? This old gun doesn’t have thrust washers.
Matt,
I don’t remember what model air rifle you have, but your solution sounds like something an airgunsmith would do. Maybe a thin steel washer instead of rubber, but that’s all. Short of recutting the threads on the bolt I don’t know what you can do.
B.B.
I have a difference of opinion with most of what I’m reading about break barrel accuracy. Some are saying that the good guns have no issue with barrel positioning if the pivot tension is properly adjusted. At best, this would mean we understand that there is some presence of rifles where the breech lock IS an issue. I use a laser that’s barrel mounted to co witness with my scope (which has a solid one piece receiver mount with a customized stop). I don’t use the laser all the time. I just use it for training, sight in of my scopes and to troubleshoot opportunities to improve my shooting. I’ve learned a lot about where the variability comes from in my groups by using this setup. My go to rifle is a .22 Walter Talon Magnum with gas piston and some tuning. The barrel NEVER returns to the same detent regardless of barrel pivot tension. I have to manually settle it into position myself. If I do this the same every time, the results are very good. The barrel has always drooped way way down from each recoil. I don’t know if my ballistic/artillery hold is just compensating for this or if the pellet is already gone by the time this occurs. The chisel detent is a piece of crap in my opinion. I’ve tried cleaning it, using every manner of dry and wet lube, and adjusting the pivot tension. Maybe other Walter Talons or Hatsan 125’s do better.
Regarding the value of the laser… Whenever my groups wander, I check it with the laser vs the scope. Sometimes I learn that my trigger control or my hold technique have begun to evolve into bad habits. At least the co witness method helps me identify this. It’s the most valuable piece of my setup to help me stay abreast of the factors that influence my shooting. Sometimes the scope DOES move in spite of all of my precautions. I can detect this too. Lastly, I have experimented with the position of the laser along the length of the barrel. The weight of the mount and laser can suffice as a harmonic damper if I get the position right. It’s smoother to shoot and the groups get TIGHT.
I’ll keep this rifle as my go to for pests and small game at 20-50yds. I can hit quarters easily at 50yds if I follow my recipe for precision and accuracy AND if I manually settle the barrel between every shot. The power is very predictable with Kodak copper heavy rounds and a barrel that’s cleaned plus 3-4 shots.
Tornado Bones,
Welcome to the blog.
B.B.