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Scopes – Part 2Scope mounts – How well do they need to fit?

by B.B. Pelletier

Chapter 1, Part 1, Selecting a scope

This is an ongoing tutorial that I hope to turn into a book on scoping airguns. Chapter 1, Part 1 was all the way back in November, and I bet you thought I’d forgotten about this project. I haven’t, but other things kept cropping up. There will be more to Chapter 1, Selecting a scope, but today I want to begin Chapter 2 on Scope mounts.

This subject is daunting to those who haven’t scoped an airgun yet and emotionally charged for many who have. I make no claim to be an expert in this field, but I bet I’ve made as many mistakes as anyone who ever scoped a gun. Through the benefit of those mistakes, I can discuss scoping with you. Today, I want to talk about how the scope fits the rifle – specifically, the width between the dovetails.

Back in 1998, Dan Bechtel, the founder and then-owner of B-Square, enlisted my help in measuring the width of airgun dovetails. He started this project because B-Square was encountering wide variations in the width of what the industry called an “11mm dovetail.” I want to make it clear that I am only talking about straight airgun dovetails, not Weaver or Picatinny dovetails.

Physical description
Bechtel told me we needed a standardized method of measuring dovetails, because how you measure them determines their width. You cannot simply measure from the sharp point on one side to the sharp point on the other side, because that will tell you nothing about the depth of the dovetail grooves. The depth and the shape of the grooves matters a lot to the fit of the scope mount.

We settled on the method of laying a one millimeter-diameter pin into each dovetail and measuring across from the outside of one pin to the other. I hope the drawing I provided makes this clear to you. Since the one millimeter pin would only go into the grooves so far, we were always measuring the same way, regardless of the angle that was cut into the dovetail.


To measure the width between two dovetail grooves, one millimeter pins were inserted into the dovetails on either side and a dial caliper measured the distance between the sides of the two pins.
For more than 6 months, I measured as many airgun dovetails as I could lay my hands on. B-Square technicians did the same. From this data, B-Square compiled a list of scope groove dimensions for many models of air rifles. They learned, for instance, that a “standard” 11mm dovetail can measure less than 9.5 mm or greater than 13.5 mm…and anywhere in between! Then there are rifles whose bases are different, such as the Webley Patriot/Beeman Kodiak and the FWB 121/124/127, which have cross-slots to accept half-round pins as a scope stop system. From that data, they started building their scope mounts to fit specialized situations. They also tried to make their common scope mounts fit as many air rifles as possible, and therein lies today’s lesson. How they accomplished that task, now that you know what they were up against, determines how well their scope mounts fit various rifles. Allow me to illustrate.


This is the end of the original B-Square AA adjustable one-piece mount made to fit the Webley Patriot/Beeman Kodiak. Read the text to learn its features.
Original AA mount
This mount is made to fit a single air rifle – the Webley Patriot, which is also the Beeman Kodiak. Its clamp is the same one found on all original B-Square adjustable mounts. Notice at the top of the separate clamp, the point isn’t sharp but rounded. It’s a ball end that will pivot in the specially prepared groove into which it fits. Therefore, the bottom of the clamp can extend out farther or in tighter and still fit correctly. However, the gap between the clamp and the body of the mount will not be the same size at the top and at the bottom. This difference disturbs some airgunners and has convinced a lot of them that certain mounts don’t fit certain air rifles correctly. The fit seen here is nearly perfect, but what you see here is not often the case. It only fits this well because this mount was made specifically to fit the Patriot it’s mounted on.


Same mount from B-Square today, only this one is made in China and the specifications were changed. You can see that the top of the clamp is now pointed and so is the socket into which it fits. The angle of the clamp disturbs a lot of shooters, but in fact, the mount is still correct.
B-Square started sourcing their adjustable mounts from China and the original specification did not make it into the contract. The Chinese manufacturer uses more conventional extrusions instead of the ball-and-socket arrangement B-Square designed. Their mount still fits and works fine, but the clamp is now stuck way out on an angle and disturbs many shooters. In fact, the scope stop pins are what aligns the scope mount and the gun, so even though it looks like this, the mount still works.


A one-piece mount on the Benjamin Super Streak has no groove for the clamp at the top, so almost all installations will be uneven, like this. Benjamin ships the gun with the scope already mounted, so this is a factory installation.
When other manufacturers start turning out scope mounts, they may never have given them the thought B-Square did initially. As long as they clamp and hold, they’re sold. The truth is that if they hold solidly, they’re okay. But, they may not look as good as some other mounts. The scope, which is a round tube, can be set up level, even when the rings that hold it don’t look right.

The bottom line
Brownells sells special centers for the precise alignment of scope rings. Many shooters will have their scope rings lapped by a special tool before mounting a scope. Do guns that have had these measures perform any better in the field? Sometimes they do, but often they don’t. A well-mounted scope has more to do with the rifle than with the scope mounts. That doesn’t stop some shooters from wanting things to look right.

Beeman used to sell the SS2 scope with different sets of separator pins to keep the clamp leg parallel to the main mount body. The scope mount was built into the scope, and Beeman understood how shooters worry about the look of their rifle.


Obsolete Beeman SS2 scope had several different sets of pins to hold clamp jaws at the best-looking angle.
What do you do?
If the look of the scope mount bothers you, then get it fixed, because things like that will play on your mind and erode your confidence in the rifle. As you are doing so, however, don’t think for a moment that the appearance really matters. The clamp can be splayed way out to the side, but the gun will still shoot fine. Never underestimate the aesthetics of the rifle. For some shooters, they’re everything.

author avatar
B.B. Pelletier
Tom Gaylord is known as The Godfather of Airguns™ and has been an airgunner for over a half-century, but it was the Beeman company in the 1970s that awoke a serious interest in airguns. Until then, all he knew were the inexpensive American airguns. Through the pages of the Beeman catalog, he learned about adult airguns for the first time. In 1994, Tom started The Airgun Letter with his wife, Edith. This monthly newsletter was designed to bring serious reports about airguns to the American public. The newsletter and Airgun Revue, a sister magazine about collectible airguns, was published from 1994 until 2002, when Tom started Airgun Illustrated -- the first American newsstand magazine about airguns. Tom worked for three years as technical director at AirForce Airguns, the makers of the Talon, Condor, and Escape precharged air rifles. Today, he writes about airguns and firearms for various publications and websites. He also makes videos, and you'll find short clips embedded in some of his artices on Pyramyd AIR's website. Tom is a consultant to Pyramyd AIR and writes under the name of B.B. Pelletier.

103 thoughts on “Scopes – Part 2Scope mounts – How well do they need to fit?”

  1. BB
    I have and off of topic question?…
    you say don’t use standard rifle bore cleaner to clean an air Rifle barrel.

    What do you use to Clean an air rifle barrel. Someone on a blog suggested formula 409 Soap?……

    Waiting For the Easy RWS Diana scope
    mount to use on My 34 Panther. When can I expect this mount to be Available?


  2. Sam,

    Why clean an airgun barrel AT ALL? They don’t get dirty in the traditional firearm sense.

    Some Olympic shooters never clean their barrels.

    We don’t use standard bore cleaner because the components can destroy airgun seals.

    The new mount will be ready when it’s ready. We have gone through three prototypes so far and are hoping number four will be right, but we hoped the same for each of the first three. Don’t wait on us. Get a one-piece mount and use the directions we provided.


  3. bb
    what do you mean air rifle barrels dont get dirty?
    one of mine was so dirty after about 100 shots, that it was killing the accuracy. i bought a rifle cleaning kit, i thought it was for air guns, and the once i used it, it took 20 minutes to get a clean patch after wiping the barrel.

  4. PA Gunner,

    The “dirt” that you cleaned out was the anti-oxidant coating from the pellets. Shoot five times and your barrel is “dirty” all over again.

    The only thing that hurts accuracy is lead that adheres to the barrel. That comes out with a brush and JB Paste.

    Firearms really do get dirty with the gasses from combustion. They also lead faster than airguns.


  5. B.B.,
    In one of those articles you wrote for the TX200, you mentioned that Ken Reeves installed a roller thrust bearing on your TX200. Can you tell me more about this bearing? I am tuning my TX200 MKIII myself and this sounds very interesting in reducing the turning torque. Thanks.


  6. B.B.,
    Great blog and pics, and the last paragraph really hit home with me. Not that having the clamp bar splayed way out bothers me soooooooo much that I can’t stand it. Its more the fact that a splayed clamp means the centerline of the scope is no longer in line with the CL of the barrel.
    I’ve got that situation on one of my guns where the dovetail is extra wide and the scope is more than a 1/16″ off center. Visibly ugly. If I center the windage at 10 yards, its way off at 40 yards. You made a comment a couple of months ago (see, some things really do stick, LOL) about visualizing the line of sight CONVERGING with the pellet at a distant point.
    So I sight the elevation for 20 yards (or whatever is appropriate) and sight the windage as far out as I can shoot accurately.
    For me, that seems to give the best overall flexibility, and stops the pellet form DIVERGING horizontally from the line of sight.

    I sometimes visualize it as the gun layed on its side and trying to compensate for the scope mounting height, without having the pellet cross over the line of sight. If that makes any sense.

    It seems like the B-square adjustable is really the only mount that has adjustment to bring the scope CL into alignment with the barrel CL.
    Is there any other mount with that lateral adjustability?

  7. B.B.,

    Thanks for the great article on mounting a scope! As you know, I’ll be tackling mounting a scope in the near future for the first time. My question is this: previously you had suggested some scope mounts for my R7 that were not made by Beeman – the Accushot mounts. They are quite a bit cheaper than the Beeman ones but would I be better off using Beeman scope mounts on my Beeman gun? I don’t mind spending a bit more if there is a possibility that the Beeman mounts will indeed work better or be less problematic in the long run than the Accushot mounts.

    Thanks in advance!

  8. Alan,

    The bearing he used was a little larger than a quarter. It had about 20 roller bearings arranged radially like the minutes on a clock face. There was a thin washer above and below the bearings that rotated on the bearings.

    This assembly was placed behind the mainspring at the trigger end, and when the mainspring twisted as it decompressed, the bearing took the hit rather than the rifle.

    The bearing is a stock machine part, though I have no source for it.


  9. Alan and B.B.,
    These look like the thrust washers, but I have no idea if they are the appropriate type, are the right size, or would hold up to the pounding. The second part number would definitely need some hardened and ground back-up washers or you might end up with a bunch of little needle bearings flying around with the spring.
    part numbers
    BTW, mcmaster.com is a dangerous site for tinkerers to linger on. LOL.


  10. Nice article on scope mounting. One thing I noticed you didn’t cover, certain scope mounts (Leapers, CenterPoint and perhaps others) provide a limited ‘adjustment’ capability in the form of a clamp plate that has two different width extrusions. By removing the clamp plate and inverting it, you can alter the effective width of the clamp. For example, in your photo of the Super Streak, you can clearly see that the clamp plate has a smaller extrusion at the top than at the bottom. It is also canted-out at the dovetail groove. If you flip over the clamp plate on this one and put the smaller extrusion in the dovetail groove, you may get a better fit.

  11. B.B. There’s a quite a bit of controversy among spring gunners about using thrust bearings to reduce spring torque, as they’re not designed to withstand the impact of the spring and can fall apart leaving all kind of small parts inside of your rifle. To the best of my knowledge only one pro tuner offers those bearings as an optional item in his tunes. Do you know of any manufacrurers that would use them in new rifles?


  12. B.B.

    Does it make any difference how far apart the mounts are from each other for a two piece mount? For the IZH 61, they have to go as close as possible to fit, but for the BAM B30 I’m going get and the scope that I plan for it, there will be room for choice. I hope your invention is out by then.

    Pyramidair should restore your Voice of Pyramidair material for callers waiting for a representative. Their elevator music sucks.


  13. BB and Chris,

    I use 2 thrust washers with grease between them so there isn’t a chance of the balls or needles coming apart. I don’t see why they would come apart anyway with the constant pressure from the spring on the bearing. The hardened bearings might eventually disintegrate from the shock loading though, and leak chips out then, which would wreak havoc on the piston, seals and cylinder walls. The metal of the thrust washers is soft, and would only eat up seals, not requiring major rework. I can’t see this happening with either type of bearing even at 50K shots through the gun. Even so, it would be advisable to clean them up and re-grease them from time to time.


  14. Chris,
    You could also say that no airgun manufacturer uses heavy tar, or does a 100% precision deburr, or custom fits each spring and guide. Standard factory design and manufacturing practices are not (I hope!) the benchmark to which most custom tuners aspire.

    In my VERY limited experience, I am aware of 2 custom tuners (ok, don’t laugh too hard) that use thrust bearings. Without empirical data, I think the effectiveness is mostly opinion.

    But I have compressed an airgun spring from freestate to coil bind in a fixture with one end supported on a thrust bearing, and observed that it unwound approximately 30 degrees during compression. Still, even when almost fully compressed, I could easily twist the spring +/- 45 degrees on the bearing so I’d say the torsional load was minimal. Add some velocity to the equation though, and who knows.

    Just my 2 cents.
    P.S. Sorry for posting so much today!

  15. BB and Pestbgone,

    Why would you want to use Nitrogen in a PCP? Air is made up of approximately 78% Nitrogen anyway so it would seem like Nitrogen would be similar to air.

    That said, the first fill I got from a gas/paintball shop for my converted 850 AirMagnum was Nitrogen. Being a gas shop, they bought Nitrogen tanks and used it for filling paintball tanks.

    I do wonder what effect using other gases would have, for example Helium. It would be interesting to experiment with different gases in the same gun (no flamable gases of course). Has anyone done this? I suspect one reason CO2 guns have lower velocities is because the speed of sound in CO2 is lower.

    Approximate speed of sound in some gases, air: 1100 fps; Helium: 3200 fps; CO2: 850 fps.

    .22 multi-shot

  16. bb,

    I got my pellets today, and I am somewhat disappointed in the shipping and handling. The box that they came in looked like it was used more than once, and by that I mean it was crumpled (like an accordian) and stained with quite a few stains. Of course, It’s just a box and I don’t care if it has been used once or twice before (recycling is important).

    Unfortunately, the pellet tins were in almost as bad shape. The Kodiak tins were covered in dents and the cardboard/paper backing on the Benjiman diabolos was folded over and crumpled. I thought that Pyramyd AIR sold dented tins for a reduced price? 😉

    The premiers box was also crumpled and had a hole in the bottom of it! The paper saying what I bought appeared to have been shoved into the box as it was torn and crumpled too!

    Now, I’m not saying it was Pyramyd’s fault, but is there any way to find out? I think I’ll just play it out this time and see how my next order comes. I’ll probably place a complaint or something then…

    Are lead pellets affected by a tin being dented? The force needed to dent a tin wouldn’t stop with just the tin, would it? Wouldn’t the momentum carry through the soft lead pellets and also distort the ones closest to the impact? (imagine dropping a box of tightly packed glass objects, the pressure that is already there will help keep some glass from breaking but there would still be cracking and breaking in other pieces)

    On a lighter note! It’s too dark to try out the pellets tonight, but tomorrow after school (if it’s not too windy) I’ll definately be testing their mettle!


  17. BB,

    Thanks for the blog on scope mounts. You mentioned the scope stop pins are what align the gun and scope. What if there are no stop pin holes? How do you align in that case?

    I mounted a Bug Buster 2 on my 850 AirMagnum (with the recommended Accushot rings), and adjusted the windage to its maximum. It still was off. I took the scope off and haven’t gotten back to remounting it. If I remember correctly, the rings looked tilted in one direction (so the gun and scope wouldn’t be aligned). I’m hoping after your series, I’ll be able to figure this out.

    .22 multi-shot

  18. Ooops :-*, sorry BB. You are the wizard though, no screen for you (at least not since you revealed yourself)! I’m sure you have more to say than I wrote!

    Insomniac, I got a tin of RWS Superdome pellets in a dented tin too. It was well wrapped in bubble wrap so I don’t think it was damaged during shipping. I haven’t contacted Pyramyd to ask about it.

    .22 multi-shot

  19. 22Multi: glad to see you have been able to “sneak away from family obligations to blog!” Have you seen the new? Walther 1250 Dominator? Is thhis not an Umarex 850 on air like you have been developing?? 300 bar, WOW!! 2500 psi. would be good! 4300 psi. ,HIGH PRES. air, STEEL TANKS ONLY!! Anyway Walther is kind of PRICEY comp. w.850!Look forward to more info on your air conversion!!Tim in S.C. ( Drag. Slay.)

  20. BB. #1 do you think a GRT111 trigger will fit a new Benjamin, Streak? #2 since you have one, can the muzzle break be moved forward, like on my G-1 & create a “hollow” chamber in front of muzzle??As I posted before, that 3″ “chamber” along w/ modded “small exit hole” in breaak results in very near zero muzzle blast!! Thanks to 13 part tuneing guide by you Im making real progress towards MY GOALS w/ springers!! Thanks BB.! Tim, AKA Drag. Slay.!

  21. shooter, I use 1 polished and moly’d stainless steel washer 😉 I don’t think I would ever be brave enough to put a bearing inside any springer.

    pestbgone, I am a cheapo, so my most expensive springer is a CFX, however I would imagine that more expensive rifles with closer tolerances wouldn’t need spring tar… as per precision debur and guide fitting I can’t say as I never shot a high end springer. Factory standards are not a benchmark by any means, but I’m sure at least one manufacturer would have tried the bearings if they worked so well! I have heard of springers with multiple washers or even multiple springs (opposite twist) to eliminate torque, yet never a simple bearing…

    That’s my $.02 🙂


    And yeah, it’s just a matter of opinion.

  22. Chris,
    Experimenting and tinkering are two of the many things I really like about this hobby. I tried a needle bearing thrust washer in a Gamo Shadow 1000 for probably 1500 shots and then took it out to experiment with a longer spring. The bearing still looked and felt fine, but honestly, I couldn’t say if it helped or hurt. Your polished and lubed washers probably did just as good a job. In a way I think the cheaper guns are more fun because I don’t feel guilty about a failed experiment. Doing something like that on my Diana 54 would seem, well, maybe a little irresponsible.

    No matter what, its always good to hear new ideas.

  23. Dragon Slayer,

    “All work and no play makes Jack a dull boy!” ‘Fraid I haven’t gotten past the computer keyboard though.

    Yep, had my eye on the 1250 until I saw the price! I don’t know if I’ll be able to get up to 800 fps (in .22) without changing the hammer spring, but that is my goal. If so, the conversion price beats the 1250 price hands down!

    .22 multi-shot

  24. 22 multi-shot,
    I’m going to try not to mess up BBs compressed gas blog, ahem, but I know there are areas where it is easier to find a place to fill your nitrogen tank than to find a scuba shop.
    I’ll hold my other questions for the blog.

  25. BB,

    Any idea on when the Super Streak will be ready to ship out. I check constantly to see the expected dates,but they’re having a tough time keeping the dates solid. Also i’ve read your posts on the gun itself,and was wondering if your finished on testing the overall performance.

  26. BB, Chris and Pestbgone,

    I did many things to my TF 99 when I put the thrust washers in and they all added up to a smooth shooting, consistent gun. Like you BB, it’s impossible for me to tell whether that single mod added anything or not. The gun never had a really bad torque problem before anyway due to its weight. It’s a pretty heavy gun. It does seem to show a bit of improvement, or that could be everything else I did to it. Those cheap Chinese rifles make for some nice test beds if you have any ideas that you want to try out before working on a nice gun. Like you said Pestbgone, that’s part of the fun of this hobby.


  27. .22 Multi-shot,

    Here are two suggestions to correct your scope situation.

    First, try reversing the rings and turning one or both of them around. That’s the way some top field target competitors do it.

    Second, try a longer scope on that rifle. The Bug Buster is short, so any angular imperfection is magnified. If you can get the two rings farther apart, the error may not be as large.


  28. Dragon Slayer,

    I will see whether the GRT III trigger fits the Super Streak. I told Charlie da Tuna I would try it for him. The trigger looks like a Gamo, but a much older one from the ’90s.

    There is an Allen setscrew on the muzzle brake. I’ll give that a try, though the muzzle report isn’t where most of the sound comes from.

    If there is anything to report, I’ll blog it. Otherwise, I’ll mention it at the start of a posting.


  29. Bob Lee Swagger,

    I have completed my test of the .177 Benjamin Super Streak. However, I am going to see whether the GRT III replacement trigger blade from Charlie da Tuna will fit the rifle, so there may be one more unscheduled report.

    I don’t know when the rifle will come in. They come from China and are no doubt on their way to Crosman at this time. That is why I resisted testing the rifle for over a month – so I wouldn’t create a demand that could not be satisfied.

    At some time in the future, I would like to test a .22-caliber version of the rifle, as well.


  30. .22 Multi-Shot,

    Looking forward to your take on the 850 Magnum conversion also. Are you one of the people that snatched up the PSI Fixed N2(13ci 3000psi) tank at a website (that will remain un-named) before I got a chance to get one….lol? If not, what brand/size tank did you wind up going with, if you don’t mind me asking?

    I have two I want to convert, and also kringed at the 1250 Dominator price. I can think of other PCP’s I would throw that kind of money after before I would the Dominator.


  31. B.B. & Insomniac,

    For what it’s worth, when I ordered my R7 I also order two tins of Beeman pellets. One of the tins was damaged pretty good on the edge which appeared to not be from shipping – the large box with the R7 and pellets looked fine and the other tin of pellets was fine. At the time I felt that they must have missed seeing that the one tin was dented before shipping it to me.

  32. Hi BB!

    A friend had the same problem pestbegone had… the scope on an AF Talon was not align with the center of the gun after adding the tri-rail. I solved it with shims… but my friend don’t like shims. Will a B-Square adjustable mount solve this problem without the shims?

    See ya! Give us some headsup about your book!

    PS… Am I right to think that nitrogen would not be bad (or much better) than regular air on PCPs? 80% of breathable air is nitrogen… but it may improve a little consistence of the shots (N2 behaves better than mixture of gases under pressure/temperature).

  33. Hey there B.B. Speaking of B-Square scope mounts, I sent the following e-mail to B-Square:

    “I’m using your airgun rings, part number 10101. I seem to have a lot of problems with slipping: the scope slips on the rings and the base mounts slip on the rail. I’m afraid if I get things too tight I will damage something. What torque should be applied to the screws of the base mounts to prevent slipping on the rail? Also should the top half of the rings completely touch the bottom half when they’re torqued down, or should there be a gap between the top and bottom halves? What torque should be applied to the screws which secure the top halves to the bottom halves?”

    What I didn’t specify was that the slipping problem I’m having is with the front ring – I have a scope stop on the rear ring and it doesn’t seem to be a problem.

    They sent back an e-mail saying I needed a scope stop (which I already knew) and that all screws should be “tight.” Well this was less than helpful. “Tight” can mean anything from “snug” to “Rats! I just stripped the threads!”

    I was wondering if you had any input on how tight the screws should be on the mount or other tips on preventing slippage on the front ring.

    Thanks for your help.

  34. Thanks BB, I will try that.

    Naw, I didn’t snatch that tank, I got mine in 2006. I can’t tell you where for reasons I also can’t reveal – LOL. Let’s just say I was fortunate. My tank was made by Catalina Cylinders.

    I did buy a small, used, 13.7 ci tank on EBay for about $25 (tank only). I had to have it hydro’d for another $25. It is made by Submersible Systems, Inc. (Spare Air). A new one (tank only) can be purchased from them for $140.

    If the conversion works out good, I will probably buy a 22 ci tank for more capacity.

    .22 multi-shot

  35. Raphael,

    Please hold the nitrogen questions until I can blog it.

    Yes, the B-Square adjustable mount will correct for any misalignment. Have your friend check the tightness of his bushing screws, too. That’s enough to throw him off.


  36. Slipping scope,

    What you describe is impossible. The front ring cannot slip if the back ring is anchored. The scope tube binds them together. You say the base mounts (the claws of each ring) slip on the rail, but then you say the rear ring is anchored and only the front ring slips.

    Are you using the term slipping to describe something else? Slipping means that the ring is traveling along the scope rail. But if the back ring is anchored, the scope will hold the front ring in place, regardless of whether it is tightened down to the rifle or not.

    Or haven’t you tightened the scope in the rings properly?

    Please get back to me and describe what is happening, because I’m having a hard time understanding it.

    As far as torque goes, do you have a torque wrench with Allen bits that measures in inch-pounds? Because I sure don’t. I don’t even know if one is made. The ring tightening procedure takes care of tightening the rings properly. Read the procedure in this article:


    The top half of the ring should NEVER touch the bottom half. Read the article and it will describe how to tighten the ring caps.


  37. .22 Multi-Shot,

    Thanks for the info about the tanks. Like I mentioned, I am anxious to see how that 850 Magnum conversion works. If you have a link where you are updating your experiences, please share (if you can). I’ve been converting the hell out of 1377C’s (its almost addictive), and am now going after a 2260 to convert.

    Also, thanks for the info above about the sound barrier in air being at 1100fps. I reported that I thought the loud crack of my Bam B30 was because the pellet might have gone super-sonic, but now that I think about it, it was probably just a detonation that I heard. I should have realized that if I’m getting 805-815fps with 10.6gr Kodiaks, then 8.8gr FTS’s aren’t going to approach the sound barrier. I guess the 8.8’s were probably too light, or with it being the first shot some fuel was ignited. Details…details…

    I’ll probably retry the 8.8gr pellets another time, after I have truly broken in the rifle. The trigger on the .177 caliber isn’t too bad. The trigger on the .22caliber sucks in comparison to the .177 now. I can live with it, but I ‘ll have to figure out the adjustments.

    Serial number for .177 caliber is #0500320. I don’t know if this means the 500,320th rifle, or the 320th rifle of 2005, or one of many rifles produced on the 320th day of 2005, etc. The serial number for the .22 caliber is #0700032.

    Thanks again

  38. BB. Thanks for your answers to me on Super Streak!!After your latest Pod Cast Ive decided to get one, but am waiting to see about GRT111 triggerfirst! I know most of the noise comes from the power plant, But my mod. to my G-1 ( moving forward,& reducing muzzle hole dia.) Virtually eliminated ALL muzzle blast!. (muzzle break) Cros. G-1 Extreme,Sorry!. I did apply some synthetic black grease to main spring & WOW what a differance!! My friends as well as myself are AMAZED at how quiet this thing is!! Really THUMPING w/ 8.8 crow mags. and VERY ACCURATE!! With all the guns I have now this 125$ one has become my GO TO GUN!! I LOVE IT!! Thanks BB. Tim in S.C./Drag. Slay.

  39. Skq. Killer You stole my best buddys nickname!!(just kidden) but in our club thats his handle!! As to speed of sound, this has been a HOTTLY debated subject among our club members! MY understanding, is that it varys according to atmospheric? conditions. I BEILEIVE this cause Ive noted dif. chrony. speeds that produce CRACK! ( IM not talking about dieseling) My late father who was a pilot,& knew Chuck Yeagar always told me this! I have noticed that (In my exp) It seems to vary by about 100 fps.I think it is somewhere around 750 mph.? Anyway, just my opinion, & you know what BB. says about that!!!P.S. Ask me about 2260 mods!! I LOVE the Cross. xx,s!!! Whole nuther subject my friend!Tim in S.C./ Drag. Slay.

  40. DragonSlayer,

    Been SquirrelKiller here now for a while…lol. I could be his more novice alter-personality…lol.

    I will probably take you up on your offer on 2260 mod information. When I get it I’ll most likely get the schematics and start tearing it apart, so to speak.

    I re-read my comment about my Bam’s serial numbers, and now really don’t think its feasible that they produced 1/2 a million B30’s or rifles, so its probably a year and serial designation.

    2260 should be here next week….

    Thanks for the offer

  41. DragonSlayer,

    p.s. – Saw yours and BG_Farmers’s exchange on the other blog. Couldn’t stop laughing. I read BG_Farmers last comment about [scoping that 760 if you are only getting 1/2 ctc groups at 65yards] and [taking black bears with a 760], and almost busted a gutt. I reread that from time to time when I need a good laugh. A little humor never hurts.

  42. BB.,Sorry ME again! #1 do you think P.A. will offer Super Streakw/ gas spring?#2Do you think P.A. will ever offer GRT111 trig. conversions as a package deal?? (seems like a match made in Heaven to me?) P.A. could profit, as well as Charlie Da Tuna.) (maybe bulk orders could cut Charlies profit margins I know) Just a thought. Just thinking that alot of “newbies” w/out tools or knowhow,but have seen blogs, would pay extra for such a major imp. to thier new gun?#3I know you have reported that gas spring is smoother, Is it noticeably quieter??#4 Your gonna be mad at me,,,Any hope of P.A. selling gas spring DYI kits yet?? Someday in the not to distant future,gas springs will a widley aiv. comodity, as Im shure you would reluctantly agree. In the mean time P.A. has the corner on the market,GOOD for you P.A. Air, YOU WILL ALWAYS BE BEST FOR ME !!Thanks SOOOO mutch BB. & P.A. Your redneck fr. in S.C. Tim!(AKA Drag.Slay.)

  43. Sq. Kill., If you did not go further than Farmers post on (SCOPING 760GO BACK &Finish!) It gets even more outragious!! (SORRY BB.) (all in the name of good healthy fun!!) SQ. Kill. no great scem. on 2260,, just B.&A. Boss vaulve,steel breech, &homemade moderator, Honest 600 fps. w/ Cros. prem. Oh, also Leap. Bug Buster Scope from P.A.!( My own tests seem to prove like BBs. tests indicate even better vel. w/ 18″ brl.!! (SUPER SHORT CARBINE!!) (Oh yha,all my tests have been at 70 deg. plus!)Enjoy your 2260! Read my rev. at P.A. on 2260SE,Like you mine was standard 2260 & I upgraded mine.E. Mail me for info on 0 $ 5 min.trigger job for xx.s that will CHANGE YOUR TRIGGERS!! (timmyj1959@yahoo.com) Good shooting my friend,Tim in S.C.

  44. Dragonslayer,

    I saw that Sumo actually clubbed a bear to death with his hot pink 760 (at least I assume it was the pink one, he didn’t say), but I thought you were wisely counselling restraint, so I didn’t go any further.

    I think you had a good question about hitting quarters, also. Honestly, I think I would hit about 1 or maybe 2/10 of time scoped (probably 9x) and offhand with .22LR at 50 yds., but anything more would be shocking — might not hit any sometimes. 25 yards, I might do better, but I wouldn’t count on it.

    With my little pellet rifle and open sights, I think I had better stick to 25 yards or less for the quarter. I’ve put it on my list of things to try (pellet and .22 also if you want). If I can hit more than one — I’ll let you know:)!

  45. What troubles me about the angled clamp is how the bolt heads sit against the clamp metal. I’ve noticed that the clamp metal is marked only on one sode of the hole when removing sights. The second photo in the blog shows what I mean. Only one side of the bolt head sits tight against the clamp. I would fix this by having a spherical countersink on the clamp and a matching half-ball head to the bolt – if that makes sense. Then there would be maximum metal to metal contact between bolt head and clamps as well as no shearing forces. Any manufacturers do this?

  46. Dragon Slayer,

    You must have missed when I reported in the blog that Pyramyd AIR approached Charlie da Tuna and asked to buy the GRT III trigger. He said no, he was happy with business the way it is. So that’s not going to happen.

    Will there ever be a gas sporing for the Super Streak? Someday, probably, but since the gun isn’t even available yet, it’s far too soon to know for sure.


  47. oh yea it was the hot pink one! The pink one is more accurate and is great for stopping bears out in Montana. I use it for groundhogs as well. I know thats WAY overkill but it works.

    its the best money can buy. The trigger breaks like wood at a mere 9 pounds. Its the best gun out there and will out shoot a daystate airwolf, Ripley ar5s, or theoben rapid any day of the week; and all of them can shoot a half inch at 65 yards.

    If only they made it in 50 caliber, i would be set for elephant.


  48. Scope mount screws,

    Yes, you have a great idea for the screws. And the number of makers you are looking for such things is zero.

    Scope mounts are like underwear. Most of us have them, but only a few people get excited about them.

    Yes, your screws are decidedly better than what we have now, but who’s buying?


  49. bb,

    I’m going to order the Crosman b272 4 piece intermount for my Benjiman 392. I already have a Simmons 4×32 scope, I used to use it on my .22 LR Rifle. Do you know if this scope would work with a pellet rifle, or should I get something else? I know that pumping the rifle would be more difficult, but I’m fine with that.

    I’ve tried the pellets with the 392 and so far the Crosman Premiers appear to be the worst. They got larger groups than I get with the Crosman Wadcutters! The Beeman Kodiaks appear to be best followed by the Benjamin Sheridan Diabolos (which would lead me to believe that the Premiers should be doing better, but maybe I got a bad batch? They seem to have more deformations then the other pellets, mostly squished skirts). I’m gonna go back out and shoot shortly as I’m aiming to improve my shot.


  50. Insomniac,

    Your scope should work fine.

    The BS Diabolos are Premiers in another package, so they shouldn’t be different from the other Premiers. Are the other Premiers from the cardboad box or from a tin? The tinned ones have fewer controls in manufacture.



  51. bb,

    I came back in to get out of the cold (the wind is picking up now)and as I put a pump into my 392 I noticed that there seemed to be movement of the barrel. Sure enough, just about every screw was loosened on the gun. I’m surpised that I never noticed.

    Also, I’m not sure but I think the 392 may be leaking. If I pump quickly I can feel the pumping increase in difficulty with every pump. But when I pump slowly it seems as though there is not nearly as much difficulty with every pump. I can also hear a crisp crack sometimes when I shoot, and sometimes I don’t hear that crispness, but rather it sounds like I put few pumps in the gun.

    Too bad I don’t have a Chronograph. I’m ordering some Pellgun Oil with the b272 intermount, I hope that that will help.


  52. SUMO:Just read about your pink 760 Crossman. I found out like yoy too the pink IS more accurate,,,CHOKED BARREL!! BOY have I got news for you! 50 cal.?? Wait no longer my airgun friend!!I just got invited on an African Safari!! Were all going, Tom Gaylord,Dennis Quakenbush,Charlie Da Tuna,Jim Chapman,Paul from P.A.,Paul Capela, Bill Dance,&BB. Peliteir, (If he can get someone to sit in for him)!!! Now the news youve been waiting for,, Today in my gunsmith shop (back porch w/ tin roof) I discovered that my 50 cal.Drag.Slay. barrel fits Cros. 760 w/ VERY little mods from my trusty Craftsman drill press!! W/ GRT-2008 trigger installed WOW!! Will be selling conv. kit when I return, PLEASE keep this between us untill my patents come thru! Have changed out stock & forearm back to brown plastic,,(keep them guessin ya know!!)Have not Chronyed yet, but,w/ Air force pcp hand pump piston conversion, Im guessing pushin 1000 ft. lbs.!! Anyway I have an extra elephant tag if your interested! BB. maybee you can just bring a lap tp??Tim in S.C. AKA. 760 Drag. Slay.!

  53. Insomniac: Just read your post on 392. Not shure of what loose screws your talking about??Barrel movement really gets my att. as brl. is permanantly factory connected to main chamber. Based on your post, (unless Im missing something)I would say you REALLY need some pel gun oil!! This stuff was made by HIGHER POWERS for Crossman guns!! ( BEN. Sher. and many others as well) Dont know details of history of your 392, But if youve never applied the secret sauce, I personally would refrain from shooting it untill you do so!If you have used other lubricants you may have issues, BUT Pell gun Oil sometimes can revive guns with seal/ pump piston issues! Oh he*# Just ask BB.!! Good luck my friend,Tim in S.C.

  54. Dragonslayer,

    The Pellgun Oil is on it’s way here!

    The wooden stock/frame has a large screw forward of the trigger guard that holds the metal part/barrel thing (teach me the correct jargon? the main chamber maybe?) and the wood together. There were two screws just above the trigger on the metal part (one on each side) that were also coming loose.

    I’m definately gonna put my shootin on hold until I get the Pellgun Oil. I’ll just leave a pump of air in it(if it will stay…).

    Oh ya and bb, upon further inspecting the Crosman Premiers I have to say that there aren’t nearly as many deformed pellets as I thought there was. There were 4 or 5 near the top of the box that were deformed (I can’t find any more deformed ones after those) and I had yet to see any deformed pellets in the other tins (I see them now!).


  55. Drag. Slay.,

    sure id love to kill an elephant, ill bring my hunter extreme. A 600 NE is about 1600 fps so the extreme should be adequate. LOL

    ps> i would never buy a hunter extreme, don’t worry. Its more of a joke than the 760.

    back to reality…

    Im actually going to africa this summer as i just got a new .375 H&H mag. I have only fired one shot through it at this point, but i know its accurate, as its a custom gun that i bought sited in, not “used” if you know what i mean. I’m gunna gun down a cape buffalo.

  56. 22 MULTI: Thanks sooo mutch for your reply to my 2 cents on speed of sound! I feel so much better now!!! Even a back yard shade tree ,Redneck wanta be gun smith can have some smarts!! Good luck w/ your 850 mods.!! Ill be watching posts!! P.S., could you not shim, or streach hammer spring??(just a thought) I guess some of my mods. should be priempted by, HEY WATCH THIS!! Your airgun friend in S.C.,Tim.

  57. 22MULTI:Wantabe, yhea right! Anyone W/ enough knowlege to do what you are doing w/co/2 to air conversions is alittle beond back yard REDNECK airgunsmithing!! As a SCUBA diver,(certified bel. or not ,cert. #142796) Im really comfortable w/3000-4500(steel tanks) (psi.)W/ Sherrifs dive detail we often go w/ 3500 psi. w/alum 80 cu. ft. tanks. (SHHHH!!) My little SPARE AIR (bay watch tank has airgun written ALL OVER IT!!) That thing would be great on ,,Oh say,, 850 RWS. ? Or in my op. A 392-AS?? Oh yheah ,what happened to the 392,AS ????P.S. do you have anyCrossman xx,s ?? If so im sorry OLD TIMERS!! BOY ARE THEY FUN &(CHEAP!!) Keep shootin & modn. MY friend! Tim.in S.C.

  58. Dragonslayer,

    Yes, I do own some Crosman xx’s. I own a 1377C that I have converted to a 2289 with RB pistol grips. I also own a 2300KT custom (I’m not sure whether it is closer to a 2240 or 2300T) that a friend got me. I love ’em. I plan on converting the 2300KT to PCP after I’m done with the 850.

    The AS392T seems to have been discontinued although last time I checked there were still a few dealers with them. The QB79 looks like it would be one of the easiest rifles out there to convert. You just need a small tank with a screw-in regulator, screw it in, and there you are!

    Which Spare Air do you have? I bought a used Spare Air (tank only) for about $25 on EBay just for my RWS 850 conversion. It is SSI’s smallest 3000 PSI tank. I’ve drooled over the large one since it would fit my conversion, but I haven’t found one at a good price.

    I am a SCUBA diver too! Got certified by PADI in ’75. Lost my card so I need to get a new one. Don’t know anyone that dives for law enforcement, but my best friend used to be a commercial diver with a city port. He was injured so he can’t dive commerically since his boss had the team do something unsafe. Hope you never have a tank blow on you!

    .22 multi-shot

  59. 22MULTI: Cross. xx pcp, WOW now were talkin!! I beleve Mountain Air makes some custom pcp xx,s. $440 !! Did you see my post on trig. mod. ?? You have probly done yours already, but if not, try it! I beleve you refered to it as the “SQISH” princeable? LOL.! As to tanks “blowing” ,,While it probly woul kill me from heart attack,the burst disc SHOULD give way first!!! I once had local dive shop overfill my alum. 80 tanks to 3750 psi!! Did not know untill 400 mi. trip to Fla.!!! Sorry about your friend.Good shootin my friend Tim. P.S. could you speed up your progress on pcp Cros. xx,s !! LOL.!

  60. Dragonslayer,

    I went the expensive route on the trigger. I ordered the 2300T/2300S adjustable trigger parts from Crosman and installed them in both my xx’s.

    What I’ve heard on failing SCUBA tanks is that the tank body usually doesn’t fail, the threads fail.

    Yep, I saw Mountain Air’s PCP conversions! A bit expensive for what I was looking for. I probably won’t post conversion details since Crosman was silent on my request for the working pressure of their 2260 tube.

    .22 multi-shot

  61. 22 MULTI: Ya, Im shure your Cros. adj. trig. is REALLY nice! ( Ive heard they are pretty sweet!) I just posted my mod on trig. for those that want a no cost, 5 min. mod that really helps alot. Ya, You musta figured Cros. would not give psi. rating for22,xx tubes. I could be wrong but looked to me like M.A. pcp. conv. was stock tube?? I also seem to remember thy used 2000 psi.?? Maybee they would advise you?I thought about asking them would they sell just the endcap/ fill probe, & special valve?? Keep us posted as to your findings!!Tim.

  62. Dragonslayer,

    Wouldn’t think MA is using stock tube. They do go up to 2000 PSI. Model 16 was the one I looked at (http://mountainaircustomairguns.com/model_16.htm). Maybe I’ll ask MA about Crosman tube, although if they don’t use it, they probably won’t know. I emailed them about buying a conversion kit and this was their answer, “I will not be selling tube kits because I want the gun to work properly before it leaves here. I also do not want anyone to get hurt in the process.”

  63. What are the dimensions of a “3/8 inch dovetail mount”? Is there a diagram available showing the angles, elevations, etc. of the attachment areas? Obviously it must be 3/8″ wide at some point (grin) but the rest I can not find anywhere.
    I am trying to find a way to install a sight mount for a red-dot sight to my Crosman 1088 which is lacking a top mount of any kind and I need to know the dimensions to make one out of either aluminum or plastic sheet stock.
    Of course, if such a mount can be found that I can attach or modify to attach, I will consider that as well.
    I have already determined that I could mount a Weaver type base with a modification of the available bases, but I don’t think the Crosman 290 red dot will fit that, and this gun is probably not really sturdy enough for a bigger better scope anyhow. (and it is all I really think it needs anyhow.)

    I have other questions, but will post them separately for easier reading.

    Thanks! (Great Blog site!!)

  64. Revwarnut,

    You are looking for standards for the 3/8″ dovetail scope rail. Son, there aren’t any! Every engineer designs them the way he feels they should be made and every production engineer changes them to fit the available tooling. One might have a 45 degree angle and another a 60 degree angle.

    The only way to know is to do what B-Square did and measure them. What you will find it a general grouping of differing dimensions.

    Better yet, determine what is required from the mount itself. That’s how Dennis Quackenbush does it.


  65. Chris,

    Does your Huntsman have parallax adjustment down to 10 yards? If yes, then it is designed for airguns.

    The real question is whether it can take the vibration and recoil of the 350 Magnum. That’s something only testing will reveal. But if the parallax adjusts close enough, it was made for airguns.


  66. I have a Feinwerkbau 124 from the early 80s, 99% condition, which I had Beeman give the supertune, back when. I’m very fond of it and I’d like to scope it. You mention a transverse half-round pin that would fit in one of a series of grooves across the receiver, which would function as a scope stop. There is no other hole in the receiver I could use for this, and I really don’t want to drill one. Is there a commercial mount from Pyramyd that I could use for this?

  67. Simon,

    The Webley Patriot has the same half-round grooves, only the B-Square mounts made for it have two pins instead of just one. All you have to do is remove one of those two pins and the mount will work. That’s what I use on my 124.


  68. Thanks for a prompt response, special thanks because on a weekend. I assume you mean this one, for a 1″ scope tube?


  69. Ordered, with a mess of pellets. Again, thanks.


    You ever do a comparison of accuracy with pellets vs pellets smoothed and seated by a Beeman Pell-seat?

    I suppose the blast of air would uniformly obturate even moderately damaged pellet skirts. But it’s a sufficiently cool gadget that I find it easy to convince myself that it’s doing some good.

  70. Please overlook the question above – I see you have treated the matter. (However, if this damnable cold weather will ever end, I’ll probably try the test myself.)

  71. B.B.
    I am trying to mount a Center Point 3-9X40 scope on my Gamo Shadow 1000.
    My first questions:
    1.The screws of the rings that fix them on the dovetail, should face outwards or inwards?
    2.The back sight of the gun should be removed? I have a difficulty in closing the scope’s cap as it hits the sight.Probably because the rings are low profile.
    I appreciate your answer

  72. B.B. Thanks for your answer.One more question. I remember reading an article of yours with instructions of how to adjust the settings of the scope. Am I remembering well and where it is? It seems I cannot understand well the instructions of my Centerpoint scope and their markings on the body are horribly unreadable.
    Thanks again

  73. I have mounted the scope.Now I want to adjust all setting so I can find the target successfully.Have you written any step by step instructions how to do that? How to adjust it vertically, horizontally etc.
    Can you direct me to those writings if any?

  74. B.B.
    Let me drive you crazy for a moment. As said before I own the Gamo Shadow 1000 with which I am quite satisfied. Now I want to get something better, different, provocative, unique, either break barrel or other type.And all that at around $150-200 (mind you where I live they cost double). Of course accuracy and power is a must.
    Shoot me with ideas and suggestions.

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