Monday, March 13, 2006

Spring break!

by B.B. Pelletier

Most of us still shoot springers, so we ought to be interested in what powers them - the mainspring. In this post, I'm going to talk about mainsprings and cover some of the basics a shooter should know. I'm excluding the common Daisy BB gun from this discussion because, although it uses a mainspring, the operation of that type of powerplant is different than a typical spring-piston gun.

Not a lot of info in the early days!
I've been involved with airguns for a long time, but I got into pneumatics and CO2 guns long before I started messing with springers. My first springer was a Czech Slavia imported in the 1960s by a New York City company, and it came with no instructions that I remember. I knew nothing about oiling the piston seal, which was probably leather, so it's doubtful the gun delivered more than 400 f.p.s. with light .177 pellets. I knew nothing of the proper hold for the gun, so its performance was not memorable.

My first REAL springer came from Diana. It was a model 10 target pistol that had lots of power and super accuracy. It was hard to cock, but it had an owner's manual that told me how often to oil the piston seal (one drop of oil every 1,000 shots). In those days (1976), Diana was using a synthetic seal material that slowly absorbed the oil and disintegrated, but that gun worked well for me for about six years. My next springer came from Beeman and had lots of owner information. By that time (1978), the first Airgun Digest had been published, so I knew a lot more about how to treat my gun. In those days, Beeman had us putting 10 drops of spring oil down through the cocking slot to coat the mainspring coils. Another 2 or 3 drops of silicone chamber oil went through the transfer port for the pistol seal. But as far as what any of that "maintenance" was doing, we had no clue.

I go inside
In the early 1990s, I started disassembling spring guns to have look inside. Only then did I discover that perhaps we had not been doing things correctly after all. I found most guns were over-oiled, and the ones where the spring had been oiled had shed all their grease, so the mainspring was twanging with every shot. The thin oil was creeping forward into the compression chamber, and some of these guns were detonating whenever fired. I discovered that early FWB and Walther synthetic piston seals were dissolving from the oil in the compression chamber. That situation has since corrected, and the replacement seals do not disintegrate.

Some guns lasted forever!
I saw other guns with unstressed mainsprings (no spring preload when uncocked) that were still functioning after 50 years of service. The leather piston seals may have been replaced a few times, but the original mainsprings were still working. I had no way of knowing how many shots were on these guns, but it was impressive that they worked at all. These were the BSA and Webley rifles of the teens, '20s and '30s. After World War II, most spring rifles had heavy preloads on their mainsprings that wore them out as they sat uncocked in closets for years.

The race for power!
The power race began in the early 1970s with the BSF 55, Diana 45, HW 35 and, later, the FWB 124. Once it started, mainsprings had to evolve, though it took 25 years for them to do so. During that period, we had springs with wires that were too thick, springs that were too hard and springs that were under too much preload. The result was early spring failure. Throw in the scanty instructions that applied to the guns of the 1950s but were still being packed with guns of the 1970s, and we had guns detonating from too much oil and mainsprings shedding all their grease. The late 1970s, 1980s and the early 1990s were hard times for springers.


This 15-year-old FWB 124 spring has numerous kinks from breakdown of the steel structure in the spring wire. Too much preload! When a spring looks like this, the gun buzzes as it shoots.


The hobby airgunsmiths did their damage!
While all this was unfolding, there arose a number of "airgunsmiths" with hammers, vice grips, kitchen tables and the desire to go into business for themselves. The result was a flood of modified spring guns that were "powerfuller" and more "powerfuller," but they didn't last very long. During the same period, the airgun manufacturers began to understand some things about mainsprings - though they didn't always apply what they knew. The Chinese, for instance, knew that their springs were made from inferior wire, so they used other non-Chinese springs in their premium guns. Diana, to get the most power they could, had been using springs that were too hard. When their returns mounted up, they took notice. Other companies had been more conservative and either did not experience any problems or they corrected them by redesign in short order. A few companies - such as Weihrauch, Webley, BSA and Air Arms - had no significant spring problems at all.


1990s Diana 34 spring broke at either end from being too hard. All the shooter will notice when this happens is the gun becomes easier to cock. A chronograph shows a 150 f.p.s. drop in velocity in .22 caliber


What have we learned?
First, I hope you now know not to oil your spring gun too much. Those who tell you to do that are quoting from a half-century ago. Read the owner's manual and follow it! Next, I hope you understand that you don't always get more power with a more powerful spring. Often, you get just the reverse! Think twice before sending your gun off to be "tuned" by someone who may just be a "toon," himself! And, finally, shoot your gun! Get away from that keyboard, put a target out at 30 yards and shoot at it. It doesn't matter that your 100x Newtonian telescope hasn't been mounted to your gun, yet. Use the open sights it came with and experience actual shooting instead of sitting around listening to others tell you what they think! Being used is the one thing that benefits spring guns more than anything else.

We'll come back to this theme again, because there's a lot more to talk about.

20 Comments:

At March 13, 2006 7:45 AM, Anonymous Anonymous said...

So then did I do any damage to my shadow 1000 when I put 2 drops in the transfer port and left it like that for about an hour with the rifle cocked? When I first shot it it was pretty loud.

Robert

 
At March 13, 2006 8:12 AM, Anonymous Anonymous said...

B.B. Off Topic:
I began reading your blog and as a result, my interest in air guns has increased. I have an old Sheridan and I read your pages about lubrication and maintenance of these fine rifles. My purpose in writing is to get some additional information this topic.
Lubrication: 1. Where and how often and most important, which lubricant to use?
2. Years ago I was told to store the rifle with two pumps of air. More recently, I was told NEVER sore it with air in the chamber. Which is it?
3. The rifle is less accurate than I recall in the past and if I leave it with air in the chamber, the air is lost in a few hours. Is this an indication that the rifle needs service? If so, what kind of service and where can that be doe or where can I get the parts to do it myself?

 
At March 13, 2006 8:16 AM, Anonymous Anonymous said...

Last week I increased the preload of the spring by 4/5 inch in my cheap chinese springer and got twice the power. But some of the pellets (Gamo Magnum) I retrieved from the bullet trap were completly bulged, with no waist and rifling-marks all along. I know it wouldn´t be good for the spring, but do You think it could harm the chamber? Is it possible to avoid detonation by swapping to silicone-oil after a thorough cleaning with degrasser?

Alex

 
At March 13, 2006 8:19 AM, Anonymous craigjwjr said...

After reading this post, I immediately dug out the manual for my CFX. It specifically says never to apply any oil to the breech or cylinder.

Interesting.

 
At March 13, 2006 8:59 AM, Blogger B.B. Pelletier said...

B.B. is out of town. He'll answer your questions when he returns later this week.

B.B.'s assistant

 
At March 13, 2006 10:06 AM, Anonymous Anonymous said...

Hi B.B.,

Does the current Diana 48/52/54 has the problem you described?
Has RWS remedy the problem with broken spring?

Thanks!

 
At March 13, 2006 10:30 AM, Anonymous Anonymous said...

It seems that the air gun’s Springer being built today in 2006 have reached to a limit given the limitation in materials and physics. This is evidently being showcase in RWS's built Springer.

What kind of improvements do you think is possible for springs?
Is the sound barrier the limit?
Do you think we can do more research in making spring to improve the material so it does not break?

If you were the Springer air gun manufacturer, what would you do to improve today's Springer technology?

Regards,

 
At March 13, 2006 6:55 PM, Anonymous Anonymous said...

How about when you leave your rifle standing on it's butt,is this a bad way of having for say 3-4 days before taking a few shots? I notice that after about 10 shots the rifle sounds more "warmed up"

Robert

 
At March 17, 2006 9:30 AM, Blogger B.B. Pelletier said...

Robert,

I don't think you damaged your Shadow 1000, but let's not oil it again for a couple of years.

Your first shot probably was a detonation, but if your gun still work okay you didn't damage it.

B.B.

 
At March 17, 2006 9:37 AM, Blogger B.B. Pelletier said...

Sheridan owner,

Where to oil and how:

Turn gun on its back. Open the pump lever. The pump head will barely be visible in the slot in the pump tube. It is dark in color. Pul three drops of Crosman pellgunoil through the slot onto the head, then work the pump and fire the gun several times to blow the oil through the mechanism.

ALWAYS store the gun with air in it! Whoever told you no does not know that this was Sheridan's recommendation for 40 years. It is how nearly all pneumatics are kept operational.

Let's wait to see if the oiling fixes the leak you now have. It may well do so. If not, let me know and I'll tell you where to get your gun resealed.

Oil your gun this way every 6 months.

B.B.

 
At March 17, 2006 9:39 AM, Blogger B.B. Pelletier said...

Current Diana 48/52,

I think the current guns are okay. I haven't heard that they aren't.

B.B.

 
At March 17, 2006 9:42 AM, Blogger B.B. Pelletier said...

Springer limits,

You pose a very interesting question. Have we reached the limits of a spring air gun?

I will address your question in a posting next week (Mar 20-24).

B.B.

 
At March 17, 2006 9:49 AM, Blogger B.B. Pelletier said...

Robert,

You can leave an air rifle standing on its butt for years without problems. Is there something else you forgot to mention?

B.B.

 
At March 17, 2006 8:50 PM, Anonymous yarzak said...

BB

Recently purchased a springer that has really grown on me a Gamo Center (The Gamo department of nomenclature could really use a little help). The only place I have found any information on it is in the Blue Book of Airguns. A nice photo by Tim Saunders was how I was able to identify the model. Appreciate any suggestions you may have to get further information on it.

I have found the Blue Book of Airguns - Online Subscription almost as indispensable as this blog to my new found passion for collecting, tinkering a little, and especially shooting airguns (.22 pistols my favorite). What a bargain the online version of the Blue Book!! I am going to get a hardcopy as well. Speaking of hardcopys, I would really like this blog in a book or CD version (actually both would be nise:) Well I am off the basement to shoot a few.

Thanks.

Ray Ck

BTW - Springers have an advantage in basement airgunning during the winter here in New England. They maintain their punch much better than CO2 in lower temperatures (as expected).

 
At April 04, 2007 3:25 PM, Anonymous Anonymous said...

BB,

Hows it going. I purchased a Beeman gold series gh 950 about 3 months ago. Since then, I have shot about 1500 to 2000 pellets through it. One particular week, when it recieved a lot of use, I noticed a fairly dramatic loss of power. Im not positive, but I think the problem was not one of immediate onset.(more like an hour or two) So, this is what I noticed... (note that my breach is, and always has been really tight with kodiaks and crow magnum pellets.)... I load either a crow magnum or kodiak as tightly as possible, (which even before I was not able to push hard enough to fully enter the breech.)... and I shoot, but the pellet stays right were I left it. I could hear the piston go down about halfway, then slowly (less than a sec) force its way to the bottom. If I seat the pellet, they always shoot better. When I was breaking the gun in, I never had a pellet get stuck, and never seated them completley.

I thought it could be a broken spring but the cocking effort is still right at the 38-39 lbs it was before. (when pushing on a scale with the tip of the muzzle break to cock). There is no audible "squeak" of the piston seal when cocking/firing. The only noise that sounds strange is a well lubed, somewhat soft crunch sound of the spring, either being pushed over the rear guide, or into the rear of the piston when compressing to cock. Even with the lighter pellets, I could still notice a loss of power, actually, a drop of about 1-3 feet below aim point at 50 yards.

As soon as this happened, and reapeated about 5 times, I put the rifle away, and since then I have made sure that all the screws are tight(scope too), I added a few drops of gamo oil to the mainspring, and it sounds alittle smoother when cocked. I also cleaned out the bore pretty well with beeman MP5 and cleaning pellets as the manual instructs. (I know mp5 is not your favorite, but I am considering a one time application of JB compound to smooth out the barrel.) I also lubed the cocking arm and pivot points. I am assuming, that since the problem still exists, that it could be the piston seal, or something to do with the spring, such as being a little bent or something and needing moly paste to lube. Also, I am about to order some crosman silicone chamber oil for the compression chamber. Otherwise I am completley confused about what the source of the problem is, or what to do about it. As far as construction, Im almost positive that the rifle is nearly identical to that of the Beeman R1. What do you suggest?

 
At April 04, 2007 3:28 PM, Anonymous Anonymous said...

BB... by the way, its a .22 cal. Thanks in advance.

-Rob

 
At April 05, 2007 3:14 AM, Anonymous Anonymous said...

BB,

Ok, a few more things... I removed the stock to get a better look at the mainspring, and I could clearly see that it was bent. When cocking, it rubs and crunches against the inside of the spring chamber where the walls seem somewhat "dry", and also have fairly large scrapes or grooves from the resulting contact. Also, while holding the gun still, and compressing/decompressing the spring, the rear spring guide moves noticably off center to follow the bends of the spring.

I have read practically every one of your posts dealing with mainsprings. I know they take a set, or warp from dieseling and excessive heat produced in the spring chamber. My rifle has never made a load crack, or even really smoked at all due to dieseling. Im pretty sure that the problem started after shooting repeatedly while at a max rate of 6-10 shots per min.

Do you think that after shooting repeatedly, and possibly cocking the gun for about 5 min while it was hot, could've bent the spring like that? Again, the rifle is a Beeman gh950, 3 months old, and 1500-2000, shots so far with some break-in maintenance. My real question, is whether or not I should just try m2m moly on the spring/spring chamber ( or velocity tar etc.) , or call beeman (CA) and get a new spring mailed to me so I can replace it. When do you NEED a new spring?
-Rob

 
At April 05, 2007 9:22 AM, Blogger B.B. Pelletier said...

Rob,

This sounds like more than just a broken mainspring. It also sounds like a broken spring guide. If the gun is still under warranty, I'd send it in for repairs.

You NEED a new mainspring when power drops or when vibration increases. But I think your gun needs more than a mainspring, from what you say. The movement of the spring guide is a clue that it's probably broken. Is it a white plastic gunde or a silver steel guide?

Don't oil the compression chamber. Get the gun fixed. No stopgap measure will fix it.

Keep the MP5 out of the bore and stop using cleaning pellets in a springer! Unless you load at least five felt pellets, your rifle is dry-firing.

When you get the rifle back, don't use the pellets you have been using. Try RWS Superdomes and Crosman Premiers.

B.B.

 
At April 05, 2007 12:28 PM, Anonymous Anonymous said...

BB,

The mainspring guide is a steel guide, not plastic. I cant tell if the rear spring guide is supposed to be rigidly fixed ( from the trigger end) in the exact center of the spring chamber, but I can see the whole length of the guide exept for what the last coil covers. There does not seem to be a problem with the guide. The movement of the spring guide I refered to due to the fact that my mainspring has a big bend in the middle of it, and somewhat varied distances between the coils and the angle they make with respect to each other.

If you look at the picture of the 15 year old spring that you posted above, from what I can see, the spring looks like this. ALSO, the only crunching noise heard when cocking, is a really high point on the spring, about an inch away from the bottom of the piston in the cocking slot in the underside of the rifle. When I start to compress the spring, there are one or two specific coils that are high enough to rub against the entrance to the spring chamber. BUT, this only happens when cocking.

When shooting, there is no crunch, no nasty vibration, only a loss of power. It actually sounds quieter than before. It could be broken (more than one piece), or just really bent. The spring guide inst strait to begin with because the spring isnt strait even uncocked.

by the way, I only used MP5 oil to keep any rust from forming in the barrel, since I am giving the gun some down time since I cant really shot it for another month anyway. I never use less than 4 cleaning pellets, but since my rifle tops out at 750fps, 4 soaked pellets work. Most of the time, I use a light pellet and 2-3 patches at the same time. Currently I have 9 different types of pellets which I have thouroughly tested. The best ones are definately the JSB jumbos, with beeman silver stings with a close second. I also like FTS pellets, crosman premiers (and HP's), and RWS meisterkugeln match pellets. I like to shoot a variety, so I didnt really notice the loss of power until one of the big ones failed to exit the bore.

This work might be under warranty, but if it is going to take them more than a month to fix my gun, then I am more than cabable of replacing the spring and the guide. The only thing I would need is to construct a mainspring compressor.
Sorry SO long!

 
At April 05, 2007 6:40 PM, Anonymous Anonymous said...

BB,

I spoke with Beeman on the phone, and they were very helpful. They said all I need to do is send it in and they will replace whatever is necessary, as it is under warranty. I thought it would take them at least a couple weeks to do the work but hey said that average turnaround time was 4 - 5 days. And I was really looking forward to attempting the fix myself :(

Seriously though, why do you think that my spring, etc... got so screwed up after only about 10-15 days of actual use? Could it just be repetative shooting/overheating and thats it? I want to know what caused it so it doesnt happen again. For the record, my gun was only dryfired one time, and with no immediate losses. So what do you think caused all this premature failure?

I think my last question is whether or not you think they will notice that I removed the stock, or that I added less than a handful of drops of gamo oil on the spring? I dont want to void the warranty.

-This wont be the last time that I thank you for your expert advice.

-Rob

 

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