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Education / Training BAM B40 in .22 caliber: Part 2

BAM B40 in .22 caliber: Part 2

Part 1

by B.B. Pelleiter

Before I begin today’s post, here’s an update on the Evanix AR6 pistol review I promised. Josh Ungier of Pyramyd AIR told me yesterday that they sold out of the first pistols, so he ordered 100 more. He also said the grip will be smaller because the one on the first batch was quite large. He expects to receive those guns in a couple weeks, and I get the first one to test for you.

Now, for today. I was going to just shoot the .22 B40 for accuracy and let that be it, but one reader who seems to be a potential buyer has asked a lot of scope mounting questions. When I reviewed the past B40 posts, I saw that I glossed over that process. When you have the gun right there staring you in the face, it’s difficult to envision what it must be like for someone who has never seen it. I told him I’d do a special post about mounting a scope on this B40. Then, GadgetHead asked me about the sliding compression cylinder that drags on this rifle. I told him I thought it was a burr; but I said I’d lubricate it, and then we would know for sure. That turned out to be a good idea!

It’s a burr!
I cocked the rifle, which slid the compression chamber all the way to the rear. I used a Q-tip to spread Beeman M-2-M moly grease around the inside of the outer tube. With the rifle cocked, I could easily slide the chamber back and forth. I expected the lube to reduce the friction, but instead it acted like layout fluid, immediately revealing the presence of a definite burr. The dark gray grease was scraped away from just the place where the scratches are. Thanks, GadgetHead! Now I know how to fix it.

Scope stop holes
Okay, on to mounting a scope on the B40. Let’s look at the top of the receiver. At the rear of the 11mm dovetail grooves, there are three holes for a vertical scope stop pin to drop in. The stop pin is either located on the scope rings or it can be on a separate scope stop that goes behind the rear ring. The pin drops into whichever one of the three holes you select (I always use the rear one) and the pin is butted against the back of the hole. That way the scope mounts (rings) cannot move under recoil.

Use one of these three holes on top of the receiver to anchor the scope stop pin.

Scope stop
I used a separate scope stop because the 30mm rings I’m using don’t have a stop pin built in. The stop is mounted first on the receiver, and the pin is positioned at the back of the rear receiver hole.

This scope stop has a pin that sticks down into one of the holes on the receiver. This is the underside of the stop. The two white things are synthetic bumpers to cushion the scope ring when it recoils into the stop. The yellow thing is a bubble level, but I don’t use it because it’s too close to my eye to see the bubble.

Mount the stop first
The scope stop is mounted first. It serves as the reference point for the rest of the work.

Position the scope stop with the pin at the rear of the preferred stop hole and tighten it.

The rear ring is attached next. Back it up against the scope stop and tighten the screws.

Mount the rear ring
I’m using two-piece rings, so I mount the rear ring first. I slide it back and butt it against the scope stop. Even though you tighten the clamping screws, this ring will continue to slide back as the gun is fired until the synthetic cushions on the scope stop are flattened out. No amount of clamping pressure alone can keep the rings from sliding back on a recoiling rifle.

Tomorrow, I’ll finish this scope installation so we can move on to test accuracy.

author avatar
Tom Gaylord (B.B. Pelletier)
Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.

32 thoughts on “BAM B40 in .22 caliber: Part 2”

  1. Hi BB,

    I finaly got my Webley Raider Venom, and I’m having a problem with it already. It seems the air filler nozzle/plug (supplied with the rifle) does not seat very well in the filler hole of the reservoir on the rifle. When I pump, air leaks out from around the nozzle. I checked carefully, and I have followed all the directions exactly. The air is not leaking from the bleed screw. Could the filler nozzle o-rings be defective, even though it is brand new?

    Barring something I have overlooked, I will be sending the whole deal back to Pyraymd, because I’m very disappointed. (Every order I have made from them has had something wrong, defective or missing.)

    Why would this not work right out of the box? What am I missing?

  2. Could the O-rings be defective right out of the box? Unfortunately, yes. O-rings can have a defect too small to see with the naked eye, yet at 3,000 psi they pass air.

    The Webley Raider is made by FX of Sweden. They are getting a reputation for leaking guns. I read about guns sold by Airguns of Arizona and Straight Shooters that leak right out of the box, too, so I don’t think it’s a dealer problem.

    The only thing you did not say was that you greased the O-rings with silicone lubricant (diver’s silicone), before using the probe for the first time. A dry O-ring can be cut or tear when it is inserted into the fill port. That problem would not be FX’s fault unless there was a burr on the fill port entrance.


  3. B.B.

    Wanted to take a moment to thank you for introducing the Leapers line of scope. Mine is the 3-9×40 RGB MilDot. Came well packed in a 2 piece heavy box – not pasteboard. Included a generous lens cloth, sun shade, flip lens covers and an extra battery. The Leapers name is engraved in the saddle – not a stick on label. Smooth operation with no visible lube on the threads. Adjusters click precisely. Clear optics. Focus down to 5 yards with accurate yardage markings. I decided to mount it on my RX-1 but was concerned that the adjusters only spanned 5 complete turns stop to stop. Set them in the middle and to my surprise was practically perfect at 10 yards. The lens covers were too bulky for medium rings so I took them off. I think the MilDots are for a firearm – too far apart for an air rifle. I did manage to hit a 2 liter soda bottle at 100 yards holding over 1.5 dots. Unfortunatley, at 1.25 lbs, it’s too heavy for the RX-1 – I’ll probably use it on something else. It is an exceptional bargain and I am really pleased with it – hope this helps someone else.
    Thanks again
    Springer John

  4. Ah, shucks B.B.,

    Thank you, but you’re the one who deserves the credit. You’re the one who has developed all the industry contacts and everything else which make it possible for your Blog to exist.

    I think you provide an exceptional and valuable service to airgunning newcomers and amateurs. I’d bet you could teach the pros a thing or two.

    You share your knowledge, skills and experience and ask nothing in return, with one inspiring exception. You encourage and sometimes expect others to think clearly and to learn to think for themselves.

    I could go on and on until we’re both embarrassed, but I really need to work on my pithiness.


    P.S.- Those closeup images of the B40 are real nice. Really gives a good idea of the workmanship.

  5. B.B. Please accept my apology for this somewhat unrelated query but I need your advise (again): Are panoramic sights ok for airguns? I’ve been reading-up on them and I’m curious if they would work on my Drulov Condor?

  6. BB, I was not informed by anyone that I should be greasing the filler nozzle. I called Pyramyd and carefully went over all the items I would need to get into PCP, and grease was never mentioned.

    I called today, and it was discovered that I need the air hose (which I was advised by the technician NOT to buy on my first order); apparently screwing the filler plug right into the pump is not advisable. Grease was, again, not mentioned.

    I sopecifically asked them to let me know about everything I would need, and they failed. Again. I love your column, BB, but Pyramyd customer service stinks and I’m finished with them as a customer.


    Steve in PA

  7. hey BB,
    I know it isn’t your specialty but I was wondering if you’d possible do a test of the tokyo-mauri sig 226 gas blowback airsoft gun. I’m interested in moving up from springers and thought you might have some inside lines to see if its a gun worth the money.


  8. B.B.

    I remember you saying you often use accushot rings when installing scopes. I’ve got a few, and it appears the ones I have are made for a 3/8″ dovetail which is slightly smaller than the normal 11mm airgun dovetail. (and I can only find ones on the Pyramid website that say they are for 3/8″ dovetail) The result being that it tightens down, but the mount doesn’t look very well seated – it’s got a small gap between the main block, and the dovetail grabbing piece. The gap tapers closed towards the top where the grabbing piece meets the block. Is this okay? Do you have the same situation with your accushot rings?


  9. BB,

    What would you choose between a S200 and a Talon SS? I don’t you don’t like comparing air guns, but could you list some advantages and drawbacks of each so I can make up my mind? Thanks.

  10. BB,
    Can you recomend a set of B squar scope monts to mount my leapers 4-16×56 scope to my Condor. I was looking for one that adjust left to right as well as up and down.

  11. D.G.

    I had to look up panoramic sights before I could answer this because the only ones I knew of were for large weapon systems. Apparently some dot sight makers are now calling the holographic type sight a panoramic sight.

    As for mounting it on the Drulov, as long as the gun has a mounting point for the sight and there is clearance, I see no reason why it wouldn’t work.


  12. Steve in PA,

    I’m sorry you have had a bad experience. The grease isn’t something a dealer usually recommends because it isn’t always required. I only suggested it because you had a problem.

    The hose, however, is an obvious problem. There needs to be some flexibility in the filler probe when it is inserted into the gun or the weigtht of the gun will hold the O-rings under tension and allow the air to escape. Had you mentioned that in the last comment, I would have picked up on it and told you about the hose.

    Precharged guns are confusing to first-time buyers, not because the technology is so complex, but because the manufacturers are all small companies that don’t think about customer education, for the most part. In fact, only AirForce Airguns gives a one-hour instructional video with every new gun they sell. It shows the customer how to do everything, so there is no mistake. They also engineer all their fill devices so they are complete when you buy them. The other companies act like people shoud KNOW, because they all do!

    Dealers like Pyramyd AIR have customers ranging from first-time buyers to experienced PCP users. Sometimes when a new buyer buys a gun made by a company that doesn’t offer a complete support package like AirForce does, there are mistakes and omissions in the sale.

    I don’t expect to change your mind on this issue. I’m simply trying to explain how things like this can happen.


  13. Dave,

    Your question isn’t out of line at all! I haven’t been doing enough with airsoft in the past few months, but I can certainly field this question.

    While I haven’t tested the Marui Sig 226 specificaly, I do have some experience with other Marui gas guns. I find them to always be superior.

    I may be able to test the marui in the future, but I wouldn’t wait for that. Because it is by Marui I know it will function flawlessly, be accurate and work very well. You will be pleased by the quality.


  14. Josh,

    I actually had to look at some scopes on guns to see what you are talking about. Yes, a 3/8 mount will look a little strange in an 11mm dovetail. I pay no attention to that because the scope is sitting in a set of rings that are perfect circles. Regardless of what’s down below, the scope is perfectly suspended.

    I don’t pay much attention to the appearance of things. I tend to look at how they perform. I can overlook an ill-fitting ring base, but I cannot forgive an inaccurate air rifle.


  15. S200,

    There is not much to compare between the S200 and the Talon SS. The SS is superior in every way, save one. The S200 has the better trigger. But power, accuracy, noise suppression and of course power adjustment are all on the side of the SS.


  16. well, another advantage of s200 is it can be converted to a multi shot rifle, which airforce can never do… I think accuracy-wise, both guns are on the par. Air force does have better power adjustment.

  17. BB,
    Well, this question is sort of on topic. I’ve been trying to find a way to scope my S&W 686 reproduction by Umarex. The problem is attaching a base to the gun itself. The supplied sight needs to be removed and that reveals three holes, exactly what the powder S&W 686 has. Unfortunately, the base you can buy for the powder S&W has the holes spaced equally, while the screw holes on my airpistol are not spaced equally. The bases on the S&W wae site are very pricy, so I went to my local gunshop and they have a nice cheap aluminum one for only $10, but it has the holes in the wrong place. They suggested I purchase it and take it to a machine shop to have another hole drilled (at least one of the holes like up correctly). Pyramid air has not yet responded to my email and I don’t expect Umarex will have a solution. Do you know of a solution?

    Michael in Georgia

  18. Thanks, BB. Your response was well-thought-out and helpful. As I said, I think you do a great job here. If you’re willing to read it, I’ll post an update when I receive the hose and everything comes together.

    Also, I ordered some o-rings because I think I indeed nicked one, and there are no burrs, so definitely my ignorance was at fault on that one. I have gotten some diver’s silicone grease from a local dive shop to help avoid that happening again.

    Hopefully, when I have gained more experience with PCPs, I will look back on this and laugh.

    The Webley Raider Venom, by the way, is a thing of beauty. One thing I noticed is that the stock does not have much or any shellac or any surface coat. Do you recommend I have it sealed, or (gasp!) try to do it myself? (I’m not very handy.)

    Thanks again,

    Steve in PA

  19. Steve in PA,

    Your rifle has what is known as an oil finish. It is sealed, in a sense, in that the oil has penetrated deep into the wood. But it can still get dirty and absorb moisture.

    My recommendation is to leave it as it is. Many shooters pay big bucks to get what you have. The bright finishes used today are polymer-based and they also absorb moisture when wet. Over the long haul, your finish will wear very well by comparison.


  20. Hi B.B.

    I had asked a question about air cylinder hydro testing which you are going to do a blog on. Perhaps you can address what should be known before buying a PCP gun and how to maintain one?

    .22 multi-shot

  21. B.B.

    Thanks for the response about the scope rings.

    It sounds like you are saying they will perform just as well as ones made specifically for 11mm dovetails.

    I was mostly concerned about them coming off the dovetail becuase of not having the right gripping power or angle. Correct me if I am wrong in thinking that you meant they will hold onto the dovetail just fine. Thanks for checking it out to see what I was talking about!


  22. Josh,

    They will hold onto the dovetail fine as long as the ends of the mount dovetails are not rounded. The need to be pointed to get deep into the dovetail grooves. And there has to be a scope stop if the gun you’re scoping is a springer.


  23. BB,
    Here is an update on my S&W 686 scope question. I found a machine shop that said they could easily do the drilling accurately and find metric screws to fit the gun. But it just occurred to me that it is possible that the metal at the top of the gun would not be able to withstand the pressure and weight added to it. Is there any way to determine ahead of time whether or not the gun would be able to withstand the pressure. I’m not sure what kind of metal Umarex uses on their frames.
    Michael in Georgia

  24. BB,
    Ouch! That stinks! I talked to the service department at Crosman and the lady there said she only had the manuel that came with the gun. She said that since the gun was made out of metal, a scope should work. Perhaps they should get someone like you in their technical services. On the other hand, do you think a trigger guard laser would work? I also received an email from Umarex! Glenn Seiter (is that a German name or what!) said that they had an item that would work, but only for a red dot sight. Granted it would be lighter, but hanging out like that, if you bump it, it might break off the top of the gun. Perhaps a trigger guard laser would work. I just received a laser, which by the picture on the web site, I thought I could mount on the top of the S&W. I did mount it on the Marksman 2004 and it does manage to close my groups in at distance. Perhaps the trigger guard laser would help with the S&W. what do you think?

    Michael in Georgia

  25. Michael,

    Crosman is now out of the picture for Umarex guns in the U.S. Call Glenn Seiter and ask him.

    Your questions are too specific for me to answer without having the product information, which Glenn has. He is located in Ft. Smith, AR.

    Go to the Umarex USA website for phone numbers.


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