BSF 55N – Part 3

by Tom Gaylord

Part 1
Part 2

Today, we’ll take our third look at the BSF 55N. You know there was one on the American Airguns web site for sale last week, so these things are still available.

A couple readers asked specific questions about the gun, so I’d like to address those first.

Does the 55N have an articulated cocking link? Yes, it does. Articulated links aren’t discussed much these days but in the heyday of this rifle they were among the most important features. Because all spring guns buzz, makers used to try to keep the cocking slot in the forearm as short as possible to prevent the stock from vibrating. An articulated cocking slot lets the breaking barrel push the piston back without needing a long, straight link in between. That allows for a much shorter cocking slot in the stock, which dampens vibration. It also allows a sling to be attached to the underside of the forearm.


BSF cocking link is in two pieces, riveted toward the front (lower left). The steel bridge keeps the link close to the spring tube. It connects to the piston at the upper right, where the link passes through the spring tube.


BSF cocking slot is very short. The forearm is solid and it can accept a sling swivel.


Someone asked to see how the BSF sling is attached. This is how. The screw passes through the steel cup, allowing the cup to rotate a little.


FWB 124 cocking slot, in contrast to the BSF, is very long, because the cocking link is a single piece of steel. It needs this clearance to operate.

Is the scope base on the 55N similar to the one on all RWS Diana rifles today? Again, the answer is yes. The BSF had the same problem of excessive barrel droop as the Diana breakbarrels still have today. You see, in the era when these guns were designed, scope use wasn’t considered. That base is really there to accept a peep sight – not a scope. The ARH catalog states that 82 percent of the rifles will not be suitable for scope mounting! That wouldn’t fly today, so the retail side of the industry has turned inside-out making accommodations for Diana rifles that have never been redesigned to accept scopes. In a month or two, I’ll have a new scope base for RWS Diana guns that will solve all these problems, but it’s taken more than half a century for the solution to be found!

BSF, however, did do one thing that Diana has yet to do. They included a scope stop (actually a peep sight stop) in their base. A tiny Allen screw can be raised on the left rear side of the base dovetail, so the rear of the scope ring has something to bear against. Mine is missing.


Small screw raises up and blocks the rear of the scope rings. At least it’s a mechanical stop, but it might chew through aluminum rings.

On to shooting
Since Air Rifle Headquarters used 25 feet as their test distance for the rifle, I used 10 meters, which is close to 33 feet. I shot the gun with Gamo Match, RWS Hobbys, H&N Finale Match and 7.9-grain Crosman Premiers.

The trigger is a delight to use, now that I’ve adjusted it for safety. The trigger has a positive two-stage pull with a light, crisp second stage. I couldn’t ask for more.

Open sights only
The sights, on the other hand, are seriously inadequate for precision shooting. They are a post-and-bead front and a rear u-shaped notch. The rear sight adjusts for elevation only, but the rifle seems to be right on horizontally. This kind of sight is made for plinking and for close-range hunting. It does not offer a precise sight picture. Unfortunately, when I tried to add both a peep and a scope, I found out I can’t. The sight base is loose on the gun, and I see now that it’s held on by a single screw that the former owner stripped out once. That’s why the rifle had to go back for maintenance. ARH installed a larger screw that now feels like it wants to strip out as well, so I left it alone and will not use the base.

Using the open sights, I got groups with little lateral dispersion, but I couldn’t control the vertical. The accuracy is there, but these sights don’t let it come out.


Best I could do with the open sights was these five H&N Finale Match.

So, it’s a vintage gun
This is a vintage airgun and not an everyday shooter. The Gamo Whisper is as easy to cock, just as light, just as accurate and more powerful. With a GRT III trigger installed, the trigger is just as good, too. You wouldn’t commute to work every day in an MGTD, and neither would you make a BSF 55N your everyday air rifle. But, now and then, it’s nice to let the years roll back by shooting something a little simpler.

39 thoughts on “BSF 55N – Part 3

  1. I have a question (not related to 55N, sorry about that) about Crosman 1760/2260 rifles. I have 2260SE, I like it, but I also happen to like shooting with iron sights. And here comes the problem – the front sight seems to be too low on this gun (or the breech is sitting too high). Every time I try to mount an iron sight on it I end up shooting too high.

    So far I found only one solution – I mounted Williams notched blade sight (like the one on 2300S, excellent piece, by the way) in reverse at the forefront of receiver – that is the notch blade is at the front of the sight instead of being at the rear. This way it gives me full range of elevation adjustments.

    Yes, I know, I could’ve mounted it at the very rear end of receiver, but the notch is too close to the eye to expect any accuracy there.

    And it seems I need to raise the front sight a bit to use rear sights. With its curent position peep sight is out of the question completely. So, my question is do you (or anyone else – I am open for ideas) know what can I do to raise the front sight? Would the front sights from RWS Diana work? Or is my only option is to find how to replace the barrel muzzle (maybe along with the barrel)?

    Thank you in advance.

    Alexey


  2. Alexey,

    No other front sight will fit this rifle without a lot of gunsmithing except perhaps the new Benjamin Discovery sight. Call Crosman and ask if they sell it separately. You will have to bond it to the barrel.

    Or you can bond a riser to the existing front sight.

    B.B.


  3. Hi B.B. I have a Crosman 1077, alot of fun, but a rotten trigger. Lots of creep and a very heavy pull. Is there any “fix” for that? Please let us know when the scope base for the RWS Dianas is available at PA. Thanks much.


  4. Bruce,

    The RWS Diana scope base will be the biggest news I have, when it comes in. Prepare for a big blog!

    The trigger of a 1077 depends mostly on the large box magazine holder, so if that is changed, the trigger pull does, too. In time the box will break in and get smoother, but it’s always going to have a long, creepy pull. That’s the nature of the design.

    B.B.


  5. BB,

    Why is the report from a PCP so much louder than a springer of the same velocity?

    TC

    PS: I will continue to work on my artillery hold…


  6. TC

    try a PCP with a shoud (Airwolf, BSA Super10 Bull Barrel) or a Silencer attached (Airarms 410 assuming you are legally able to attach these in your area). Either of these 3 rifles that i own, and im sure many many more than i dont, are almost silent when compared to a springer of modest power. I know many US states are not able to use silencers, but surely shrouded guns are ok? They truely make back yard shooting possible as the report from the pellet hitting the target is FAR louder than any noise the rifle makes.


  7. TC,

    The PCP has many time the amount of compressed air as the springer. The springer releases a tiny amount of compressed air in a sudden burst. The PCP releases air at lower pressure over a longer period of time. Even though the pressure inside the gun may be 3000 psi, the pressure that makes it through the valve is about 1600-1800.

    The springer hits the pellet with a short blast of 2000 psi air that then expands and dissipates by the muzzle. The PCP keeps pushing with 1600-1800 until the pellet almost leaves the muzzle. Hence more air at higher pressure comes out, and it’s louder.

    B.B.


  8. wow….I given up on the AA .22 domed pellets and the JSB .22 Exact Jumbos…they just never seem to be in stock, but now the Benjamin Sheridan Discovery .22 with pump has been delayed about two weeks. I can hear the crows laughing now. Time to get out the H&N .22 baracudas and my trusty springer I guess.


  9. ajvenom,

    Crosman is seriously backorderd on the Discovery right now. It’s a case of inventing a better mousetrap and then having to supply it when the orders come it.

    They are being very careful, to get the manufacturing process just right, so there aren’t a lot of complaints and returns. That’s a wise thing to do, but it does create a backlog of demand.

    B.B.


  10. Thank you, Tom. I guess I’ll use existing front sight as a base for a riser as you suggested.

    Sight from Benjamin Discovery won’t help because it’s not any taller than what I have already – it’s height is for the rear sight mounted directly on the barrel, while I want to mount one on receiver (hence the difference in heights).

    Alexey


  11. BB,

    Having been a firearms guy all my life I’m intrigued by the physics behind the different airgun powerplants. So my next question is, why does increased distance that you shoot with a PCP reduce the number of available shots? I presume that it’s a statement regarding the accuracy over longer distances because of a drop in velocity later in a string, because the gun doesn’t know the difference between 10 yards and 100 yards, right?

    Also, you guys were discussing reduced firearms loads the other day. I assume that readers here know of the potential dangers in this with certain powder/primer combinations. PO Ackley wrote extensively about this years ago, and I’m sure there’s more recent data out there, but it’s common for folks to think that the only danger of over-pressurization comes from loading too hot.

    There have been some fine rifles destroyed (and human flesh too) shooting reduced loads with the wrong combination.

    Just threw this in so folks can inform themselves.

    TC


  12. TC,

    Thanks for the safety reminder!

    Yes, the farther you shoot, the more consistent you want the velocity to be, to keep the group together. The more shots a PCP shoots, the greater the shot to shot velocity variation. You don’t notice it at 25 yards, but at 50 it really stands out.

    B.B.


  13. In Friday’s blog you made the statement “….all of them are in the “good” category except for the Gamo 126″. Would you please expand on that. I have shot and been around several 126s over the years and they shot very well, perhaps not quite at the level of my old FWB 300S but certainly as well as most shooters can shoot. I’m just curious what exactly you meant when you made that comment.


  14. Gamo 126,

    I thought I explained the reason pretty well:

    Gamo/Daisy 126 – Needs frequent rebuilding. I would avoid it altogether

    Yes, when it works the 126 works well, but of all the single-stroke rifles I know, this one has the poorest record of reliability. In my capacity I have had to direct many more times the number of 126 owners to where they can get their rifles repaired over the years. That sort of thing sticks with me.

    B.B.



  15. Nate,

    You’ll have to contact Crosman to find out for sure, but the 2240 pistol from which the 2300T is derived is linked to the shoulder stock, however, the Crosman description doesn’t mention that number. Why would they link it if it didn’t fit?”

    Only Crosman knows.

    I think it fits, they just screwed up their website.

    B.B.


  16. Alexey,

    Have you looked at the Crosman muzzle brake? They come with a round post-style front sight that is easily removable. If it’s not tall enough for you, simply unscrew it from the muzzle brake and install a taller post into the threaded hole.
    If memory serves, the sight you currently have is press-fit over the muzzle of your gun. To remove it, place an open-end 7/16″ wrench over the barrel and tap the wrench with a small hammer toward the muzzle. Sight should pop right off.
    The muzzle brake attatches with a set screw to lock it in place.

    Derrick


  17. Diana has reportedly changed the way they are making their gun and eliminated the barrel droop they are famous for. They are now making the barrels in line with the compression chamber. These guns should start to show up soon. So no special mount will be needed for future Diana guns if they stick to there report.


  18. walkonking,

    This will be great if and when it happens. But there are still several hundred thousand guns in need of correction, plus as many as they make before this new revolution takes place, that have to be scoped.

    B.B.


  19. B.B.

    This is off topic of the 55n, but I am working on a daisy 120 break barrel and need a seal. Any suggestions, the one in the gun had a finishing nail in it. Can you imagine I guess the previous owner ran out of pellets:)

    thanks jw



  20. B.B. Do you think Crosman will have a Dual Fuel with a shrouded barrel in the not too distant future? Or how about a kit for the current one?


  21. Hi JW,

    You probably already did this, but I would check the cylinder also. That finishing nail might have scored the wall which will eat up any new seal that you put in it. If it’s scored, you’ll need to hone it out. I’d guess that guy was trying to make darts… I never worked on a Daisy, so BB will have to point you in the right direction for new seals.

    /Shooter


  22. Thanks Shooter

    Actually I am very new to the fixing of airguns so honing had not crossed my mind. I have been reading as many of B.B’s past blogs as I can trying to get familiar with things.
    The gun, I think came from a yard sale, so cost was really cheap. It’s not in to great of shape but it’s a fixer for practice. I have shot guns and piddled with them my whole life and recently caught a bug for air rifles.
    While I am thinking about it can you or B.B. set me straight on oiling the pump head of a Benjamin392. Some same oil some say don’t. What is your take?

    jw



  23. Thank you, Derrick, it’s a nice idea about muzzle break. I didn’t think one can get them without a barrel.

    Alexey.



  24. Bruce,

    I don’t think Crosman will change the Discovery. They are backordered for many months and have a huge success on their hands as it is.

    I do think the next gun they bring out will have a shroud. That will probably be next year.

    I know that several owners are experimenting with shrouds right now, so there may be something aftermarket before too long.

    B.B.


  25. JW and Shooter,

    Shooter is right that you should check the cylinder, but I don’t think you’ll find a mark. In the several guns I have examined with finishing nails in the piston seal there was never a mark in the cylinder walls. I think the nails are too soft to damage the gun and the leather seal absorbs them too well. The one you found was probably buried deep in the leather, wasn’t it?

    B.B.


  26. Revwarnut,

    No, I doubt they will name it that.

    Diana is now telling everyone that their guns are made in perfect alignment, but each new one that I test is as bad as ever. So this thing is really needed.

    B.B.


  27. B.B.

    Thanks for the web site address to find a seal.

    Three nails in one gun I am impressed and here I thought I had something crazy.

    I read your directions for building a seal and was confused on the size. Then I talked to my dad and he was explaining a seal in general and it clicked, I was picturing the seal in backwards. I plan on building my own first. Now my only problem is the petroleum oil. Sounds dump but what exactly is petroleum oil? Motor oil?

    And yes the nail was buried pretty good, I could only see a small portion when I took the gun apart and that portion was in the front not the side.

    jw


  28. JW,

    Yes, motor oil is petroleum-based unless it is synthetic.

    Petroleum is oil from the earth. It is split into fractions in a refiner. Some of the fractions become lubricating oils. If the year were 1950 I would have just insulted you, because what other kinds of oil are there?

    But in 2008, a lot of lubricants are not petroleum-based. Many are completely synthetic and developed in the laboratory rather than the oilfield/refinery.

    Yes, the open part of the pistol seal faces forward and balloons out when it’s pushed forward at high speed. That’s how it seals the air.

    B.B.


  29. Tom,

    I need your assistance please. I have two BSF model 54 underlever rifles and require a complete trigger mechanism and end cap for one. As you are well aware the rifles are old but when they come from your childhood you treasure them all the more. One rilfe was in a fire and thstock burnt as well but that I can replace. I need a complete trigger set. Can you assist me in finding such rare parts? I am based in South Africa and can be contacted at brian.minnaar@absamail.co.za





  30. You're in luck, because you can make a breech seal for your BSF 55N. The seal is probably leather. There may be some later guns with synthetic breech seals, but the two I own are leather.

    Here is a link to an article about making a leather breech seal. The article shows me using a hole punch, but you can also cut a seal from leather with just a sharp knife. So don't let the lack of tools bother you.

    http://www.pyramydair.com/blog/2009/01/diana-27-part-3.html

    B.B.



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