I bought a Wishcho marked BSF 55N recently. The gun will not cock. I knew this ahead of time so no poo-pooing of the seller. He was honest with me and the little gun is nicer than I expected.

I am a rank novice at airgun tinkering. I recently bought a spring compressor. A phone call from a friend that is a pro and I had the 55 apart without any incident.

Nothing looks amiss inside the gun mechanically. There is no evidence that the gun has ever been opened up either.

I think it may have simply been locked up with old dry lube. The trigger group would not do anything. It was completely covered in this brown goo that looked for all the world like old maple syrup. It was every where. Alcohol would not even cut it. I finally took the plunge and used carb and choke cleaner. That did the trick but I still had to use a lot of elbow grease and a toothbrush. Now the trigger group moves and sets freely.

I was careful to remove the piston seal from the piston and lay it aside before I sprayed the metal parts. I think I will be able to recondition both the breech and piston seal.

This is a very interesting design for an airgun. I do no think it has been shot much since there is very little blue wear on mating surfaces. The inside of the compression tube is still crosshatched and blued.

I would appreciate any insight or help in putting this gun back in service.

I am going to make some subsequent posts with pictures. I will break them up so as to not make it difficult to load.

Best regards, Brad

Here are some pictures of the trigger group after cleaning.

Comments are welcome.

Regards, Brad

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Pictures of the piston and seals after cleaning.

Regards, Brad

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Pictures of the compression tube of the BSF 55N.

Regards, Brad

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Pictures of the various small parts of the BSF 55N after cleaning.

Regards, Brad

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I have carefully deburred all the slots in the compression tube. I was shocked at how hard the steel was on the tube. I spent many years as a tool and die maker so I have a good idea about how hard a piece of steel is just by running a quality file across it.

I have also cleaned up the cocking arms and "shoe". The arms were beginning to gall as you can see in the pictures of the arms and the main tube underside. The cocking shoe portion of the arms was rather burred up.

I also have cleaned up the slot of the piston. I set the piston in the lathe just to knock off any high spots. I was very nicely surprised that the rod in the piston only runs out about .004" to the body. Considering the awful looking braze inside the piston, that is pretty darn straight. The piston actually is "waisted" front and rear and fits the main tube very well. I do not think buttoning th piston would gain anything since they are within .008" of each other already. Am I wrong?

The main spring measures 9.200" long, with 29 coils. The spring wire is .126" diameter. The OD of the spring is .830" and the ID of the spring is .560" . The stem of the spring guide only measures .510" in diameter so there is about .050" slop between it and the ID of the main spring. How should I address that? Shrink tubing?

The main spring was a little loose in the ID of the piston. I took some .004" stainless shim stock and cut a liner for the piston to size. It is full length of the piston and about .100" narrower than the cocking slot so it won't interfere with the shoe of the cocking arm. Now the spring is a nice snug fit in the piston. Is this OK?

Please tell me what you think so far.

The stock is currently all lathered up in a thick coat of Howard's Feed and Wax. Old wood really soaks this stuff up and it gives wood such a beautiful warm glow. I plan to let the stock soak up as much as it will and then follow that with good old Johnson's Paste Floor Wax. The stock is walnut and in very nice shape.

Regards, Brad

for posting the photos. I, too, have a Wischo 55N and have wondered about the trigger spring, which on my rifle protrudes from the stock and is visible behind the trigger. I thought it might be a replacement fashioned from a safety pin! Now I know better.

Anyway, the 55 is a great little rifle. It's actually a tad smaller than the 27 DRP I bought from you a while back but seems to weigh about the same. The difference between the two in performance is remarkable, however: The 27 averages about 575 fps with Premier HPs and the 55 generates 725 fps with the same pellet. I like both rifles equally, though, and wish both were still made.

Good luck with your project. It may motivate me to ask my "pro" to go inside my 55.

Best wishes,

Streak

That is a very curious way to do a trigger return spring.

Thank you for the velocity report. Since this little fellow would not cock before I took it apart, I have no "before" numbers to see how my work did.

It is easy to see why this little gun is well liked. It is really growing on me.

I will contionue to post as it progresses.

If this sort of post generates any interest, I will do the same for my next two projects.....an early Diana 35 and an early HW 35 Luxus.

Being very new to tinkering, I have scoured the web for "how to" posts. To my dismay, there are very few pictorial guides out there.

Now that I am retired, I have time if there is interest.

Very glad to hear that you are enjoying the DRP!

Best regards, Brad

Incredible pictures too. This should go into an archive somewhere and be kept for future reference. Looking forward to more posts like this.

Bob in WV

Never get in a hurry, it only slows you down.

I am not much of a photographer....Lol. I took probably three times as many pictures as you see here and had to chunk most of them.

I have a camera that is FAR smarter than me.....my kids would tell you that's not much of a trick.

If this post generates much interest I will be happy to do similar posts on other classics. This is actually pretty fun.

I would not be able to do any of this without Mike Driskill. He worked with me behind the scenes last year to walk me through how to post and photograph. Mike has unbelievable patience and is a credit to this hobby.

I had to take an early retirement in May because of my health so I have time to do it.

Thank you for your kind words.

Best regards, Brad

the trigger unit and the piston while the gun is dis assembled.
Try to "dry" fit it to make the trigger catch the piston rod.

This will teach you HOW they work, as most of the times the trigger unit isn't put back in the right way ,so it won't "hold" the piston when cocked.

-------------------------
Frank

I was a little curious about how all this stuff goes together in actual use.

The trigger unit was locked up as tight as a drum before I cleaned all the brown goo out of it. No part of it would move. Now I can take a nylon punch from either end of the housing and simulate the setting and release fo the trigger unit with just a tiny amount of pressure. I put just a few drops of Break Free in it just to give a little lube and now everything works smoothly in the trigger unit.

I am a little worried that I should clean all that oil out before assembly though. It has silicone in it and even though I put just a few drops, I worry about it migrating around and messing up the gun.

If I figure out this lube stuff I will post a tutorial about what I find. I have researched for hours and found all sorts of differing opinions about Moly, "tar", open gear lube, lithium grease, vaseline, neatsfoot oil, silicone oil, anti-sieze, etc.

I have been a machinist for a long time (just retired from aerospace) and I have been gunsmithing for better than 20 years now. Breaking open this little BSF has me more entertianed than I have been in a VERY long time.

I really appreciate the input Frank.

Best regards, Brad

In this morning's mail I received a package from Jim Maccari at ARH.

I had ordered a new mainspring for the little BSF. I had no idea if the gun really needed one, but Jim had one listed and I needed some lubes anyway.

Well now I am perplexed.

The spring that arrived looks quite different than the one I removed from the gun.

The new spring is 10.9" long, .785" OD and .532" ID with .120" wire.

Hmmmmm.......

Comparing it to the old spring:

The new spring is 1.7" longer, .037" smaller on the OD, .031" smaller on the ID and is made from .005" thinner wire.......if I did the math right....lol.

The spring seems noticeably softer too by very unscientific comparison.

When I received the BSF I noticed that it seemed to have a VERY heavy cocking stroke (even though it would not stay cocked).

I saw no signs that the BSF had ever been opened up. I wonder now if it had the wrong spring in it when I got the gun?

I have never ordered springs or replaced them so this is all new territory for me. Is this much of a difference in physical measurements common?

Best regards, Brad

JM knows his stuff. If you ordered a spring for a BSF 55, I'm pretty sure you got just what he thinks should go in that gun. Smaller ID equals better fit on the guide, and consequently equals better firing behavior. .120 wire diameter is just about right for that gun. Overall spring length means very little. Wire diameter times coil count is really the only way to compare different spring, (ID being essentially the same.)

My guess is that your gun is not quite as virgin as it may appear. You mentioned a rather heavy cocking effort, which was NOT a quality of the BSF 55. I'm guessing the spring you took out is not original. Keep in mind that this particular gun has been floating around out there for many years, and I'll be willing to bet you're not the second owner.

If Jim's spring fits on your guide, hopefully tightly, then put it in and see how it shoots. My guess is you will be pleasantly surprised. Like I said, he knows his stuff.

I think we're all Bozos on this bus.

Apparantly the person(s) that have been in this gun did a careful job since I saw no marks.

I will reassemble the gun and see what I end up with and report back.

I never doubted Mr. Maccari. I am sure he has forgotten more than I will be able to learn about springers.

regards, Brad

JM doesn't always duplicate the originals. For example, his FWB124 "Arctic" kit has a shorter spring with spacer so you don't have any preload, the original sticking out a good ways. And it ends up slightly hotter with the replacement.

You gun sounds like they were oiling the spring with automotive motor oil. Those guns are from the chamber lube/spring oil days. Soak your seal in some silicone oil to rejuvenate it. Those Wischo's are nice guns and well built.

Always good to hear from you.

I am going to assemble the rifle today and give it a "dry run".

One of the members here is helping me behind the scenes since I am such a noob at this. I am goint to assemble the rifle without any moly or tar and just check it for function. That way, if I do find that something mechanical is out of sorts, I won't have moly to clean off. If the gun functions I will then open it back up to put the proper lubes in place.

Thank you for the specifics of JM's FWB kit. I have never done any spring replacement so this is all new territory for me. I was not second guessing what he supplied. I am just surprised that the spring that was in the gun apparantly was not original.

I had not considered motor oil was what was used on this gun. I think you may be right. Another hobby of mine is working on small engines. The brown stuff that was everywhere inside the gun looks very much like the inside of an engine that has sat unused for a long time. Whatever it was, it was tough to remove. The gun is spotless inside now. I got the full lube kit from JM so it will have the proper lubes now.

I bought a lifetime supply of silicone shock oil a couple of years ago. I will soak the piston seal right before I seal her up. My "tutor" also advised me to try and blot off as much as I can of the silicone oil prior to assembly with paper towels since excessive oil can cause the gun to diesel.

This seems silly to say, but I am very excited to be bringing the little BSF back to life.

Thanks to all of you for all the input and helpful advice.

Regards, Brad

Don't know how I missed this excellent post! It's hard to find info on the BSF's in general, and it's great to have this fine selection of pics as a reference. Back in the days of the original Air Rifle Headquarters these guns were extremely popular, and still a textbook example of how to get excellent power out of a compact design.

As Tom Gaylord mentioned in his blog posts on these rifles, the triggers have a reputation for being rough when new, but nice when fully broken in! I've always thought their basic design owed a lot to the classic Mauser bolt-action rifle trigger, too, appropriate enough for a German rifle I guess.

I would echo what Jim said on the mainspring question. It's very typical for a replacement spring to be longer than the one being replaced; it's coil count times wire thickness that is the true means of comparison. I'll be very interested to see how JM's spring works out in the 55.

I am excited to hear this little rifle shoot. I can easily see why they were popular. It is a very nicely made rifle and it's size is fantastic for the power it should make.

Once the project is done I am going to post some side by side photos with a few more common airguns to provide some sense of scale.

I can only wonder where all of these guns went? I scour the internet for unusual airguns to buy and try. I do this daily so I think I miss very few. This is the first 55N I have run across for sale. I know that a few are owned by some members here and on the Yellow. It is sad to think of, but I believe that many fine airguns are lost each year to the trash.

Many peole outside our community seem to view these old classics as just "an old BB gun". Sadly that is what happened to the very first airgun I had the pleasure to spend any amount of time with. My uncle had, what I now believe was, a Hy Score 801 (the Diana 25, not the Belgium made model). I was allowed full access to this gun to roam the creek behind their house. I must have put 50 tins of pellets through that gun as a little kid. My uncle passed away about a decade ago. I thought of the little Hy Score and asked my aunt about it. She had thrown it away. Ugh. Well I have a duplicate of it now and it is going to get the same treatment as this little BSF.

I hope this BSF refurbishing project is well received. I would like to do a series of similar posts on other old classics.

Best regards, Brad

I too have a very good one of these in .22 cal and cannot ad more than has already been said,other than also on our side of the pond(UK)they are now very rare indeed.There has been a Swedish fellow advertising for one to complete his BSF collection for many years on the BBS without success.so throughout Europe too they are few and far between.Considering how revolutionary and popular they were at one time it is largely a mystery as to what has happened to them.They are a lovely powerful little package to shoot as you will discover.

Regards,
Mark.

As far as I recall, most, if not all, of Jims springs need to be set. He can do this for you for a nominal charge (its listed on his site). Once "set", the spring is shorter. Its just a bit more difficult to install without the set, but will set itself once installed. I have two 55's and I love 'em both.
dave