Hammerli Razor – Part 3 and the BKL introduction

by B.B. Pelletier

Before we begin, here are the answers to the splat quiz about velocities shown in Wednesday’s Splatology blog:

Splat 1: 250 fps
Splat 2: 340 fps
Splat 3: 614 fps
Splat 4: 503 fps
Splat 5: 523 fps
Splat 6: 497 fps
Splat 7: 568 fps
Splat 8: 419 fps
Splat 9: 639 fps
Splat 10: 478 fps
Splat 11: 539 fps
Splat 12: 384 fps
Splat 13: 584 fps
Splat 14: 560-580 fps

Part 1
Part 2

Two tests in one
Today, I’ll prepare to test the accuracy of the Hammerli Razor and also start another big test. Since I’m mounting a scope for the accuracy test, I decided to let the Razor be the first testbed of the BKL 260 one-inch scope mount that holds onto an 11mm dovetail by clamping pressure, alone. Describing the mount and scope installation will take up today’s report.


BKL cross-section shows how the clamping jaws will move under pressure.

As many of you know, BKL scope mounts are pretty popular among airgunners. The company went out of business some time back, but even before that happened the shipment of mounts became sporadic. BKLs are about the only airgun scope mount actively bought and sold with any regularity on the classified sites.

Auto-Numatic, the parent company of AirForce Airguns, bought the company and has been quietly producing many different models of the BKL mount line to meet the expected demand when the dealers who used to stock BKL products place their orders. The wait is about over now, as the inventory has been built up to satisfactory levels, more or less. All products may not be ready to ship, but the most popular ones are.

Installing the BKL 260 MB
The BKL 260 MB is a one-piece, medium-height scope mount with two rings, each having two screws. The mount base that clamps to the rifle’s 11mm dovetail has six screws. But that isn’t the only thing that clamps it to the dovetail. The clamping jaws are closer together than the Razor’s dovetail grooves, so before it can be installed, those base jaws must be spread. This is where BKL’s special technology comes into play. Besides the six screw holes, there are thee holes where three of the six screws can be inserted to put spreading pressure on the base jaws.


BKL 260 has six clamping screws, shown here. The three holes accept a clamping screw that can spread the clamp jaws to go on a rifle with a larger-width dovetail.

The Razor must be prepped to receive the BKL mount by removing every last bit of oil found in the 11mm dovetails. I use a cotton swab and denatured alcohol. I rub the swab into each dovetail cut with force so that the alcohol gets into the deep recesses and dries up all the oil. The alcohol evaporates rapidly and leaves nothing behind. Soon, the rifle is ready to receive the mount.


Three screws are positioned to spread the clamp jaws. When I turn them inward, it forces the jaws apart.

To spread the base, I tighten each of the three screws in turn, so not too much pressure gets applied in one place. It’s possible to see the base clamp jaws spreading, plus the anodizing in the center of the base develops a line as the metal flexes.


When the jaws were spread, the anodizing came off the center of the mount base. That metal definitely moves!

Working slowly to not over-flex the base, I finally reach the point where both clamp jaws fit into the Razor’s dovetails at the same time. Now, the three spreading screws are backed out of their holes. When that’s done, the base holds tight to the rifle by clamping pressure, alone. But, of course, I’m not finished.

The six clamp screws are inserted into their holes and tightened. I work successively down the line, tightening each screw as I go. After five or six trips down the line of screws I have the mount clamped to the Razor as tight as I believe it’s possible to go. Next, I installed some movement markers, in the form of Gorilla tape. For those who haven’t yet tried this stuff, it’s far stickier than regular duct tape. We use it on the TV show, and I’ve seen it do things I didn’t think tape could do. These small strips of tape are not going anywhere until I purposely remove them.

I place them in front of and behind the mount. Any movement will cause the tape to rise as the mount presses against it, or we will be able to see the mount move away from the tape. Either way, we should all be able to see it clearly and have no cause for argument.


Tape at the left rear of base.


Tape at the left front of base.


Tape at the right front of base.


Tape at the right rear of base. If the mount moves, it will either curl the tape or move away from it. Either way it will be visible.

It’s time to select and mount a scope. These are one-inch rings, so I need a scope with a one-inch tube. I selected a Bushnell Trophy 6-18×40 scope, and, YES, the scope does clear the breach, and, YES, the 40mm scope objective bell has clearance over the spring tube with this medium-height mount. A 50mm bell would not clear.


Bushnell scope is large but not too long for this rifle. The barrel is still an inch in front of the objective bell. 40mm objective bell just clears the spring tube.

When it was time to remove the scope caps, another BKL innovation came to light. The cap screws are the SAME SIZE as the base clamp screws. Hallelujah! Finally a scope mount maker gets it. Why put three different-sized hex screws in a mount when one will do? This is a great engineering call that shows someone gave some thought to the customer in the field. You need only one Allen wrench to do everything.

Now that everything is cinched down tight, I’ll test for accuracy. After that test, the gun will have at least 100 shots on it, so we will take a look at the tape. If it hasn’t moved, I’ll continue to shoot the rifle another 400 shots and then remove the scope and photograph the tape for you.

61 thoughts on “Hammerli Razor – Part 3 and the BKL introduction

  1. That clamp design looks very similar to the Chinese-made "BAM" one-piece mount that came with a BAM B-25S (Panther copy) package I bought a little while ago. Only it doesn't have jacking screws to spread the base out, making it a bit of a bear to install and remove.


  2. ooh, this is an interesting-looking scope mount! and yeah, i've always been mad at Leapers for making 50 different Allen wrench sizes needed for everything…

    i'm glad that Sportsmatch (Beeman) isn't alone in making only 1 Allen wrench necessary, because i think it should be this way for all of em. that clamping pressure idea sounds like a darn good way of doing things. would this work on RWS scope rails, if it works? not to see why anyone would want to with the new Leapers base, but it would be an interesting thing to find out.

    John W.



  3. BB, I remember from the previous post how the impact gives an idea of velocity at point of impact. I feel that is more important than muzzle velocity (as a hunter anyway). Have you ever set up a chrono downrange to measure velocity at target? If so, what's an average loss in velocity from an average pellet? JP




  4. I have an RWS 34 Panther that has very little, if any, barrel droop. The Leapers mount proved to have too much compensation, so I removed it.

    Now this is a very special Panther, as Tom and I gave it a tune-up for our next episode of American Airgunner. We replaced the mainspring, top hat, guide, seal and guide washer with James Maccari custom parts. We even honed (dressed) the inside of the compression chamber to make small cross-hatch scratches on the inside surface. This will help prevent galling of the Molly Paste lubricant by grabbing it.

    I installed a BKL 260 mount and a CenterPoint 4-16×40 scope on it–Now it's a given that the rifle shoots a lot smoother after the tuneup. The extreme spread was only 9.2 fps according to the chrony–very consistent, but then again, the Model 34 was always a great platform.

    almost 1000 shots later, the BKL mount has not budged. If you have a springer that needs no droop compensation, the 260 is a fantastic mount. This is my first time using the new BKL mounts, and let me tell you they are just stunning–well as stunning as such a simple accessory can be. Beautifully annodized, with a butter soft finish. Bravo!

    -Paul
    American Airgunner TV






  5. CBSD, this sort of mount doesn't tend to be as adjustable as a more conventional design. If it's anything like the BAM mount I have it is designed to work within a very narrow range of dovetail widths.

    If the Slavia 630/631 has the same dovetail as my 634, I really doubt it will work.


  6. Vince:
    Do you think the mount will not fit most rimfire dovetails?

    BB:
    How long is the mount? It looks like a good 4-5" in the photo.

    PurcHawk


  7. Paul, how fine an abrasive did you use for finishing the inside of the compression cylinder?

    The reason I'm asking is that Maccari recommends 600 grit when his seals are used, but the general advice on the internet seems to run the range from 220 to 400 grit, which Jim says might prematurely wear the seal.

    Needless to say, I follow Maccari's recommendation…


  8. Sounds like if they made a droop compensating version they'd have a winner all around for all of those who do have RWS droop problems.

    I received an interesting email advertisement from Pyramyd yesterday for gas spring airguns. The interesting part was the list of reasons to buy a gas spring gun:
    1. Smoother cocking
    2. Smoother shooting
    3. Less recoil
    4. No spring torque
    5. No spring fatigue (even if cocked for hours!)
    6. Functions perfectly in all weather
    7. Lasts longer than a metal spring
    8. Comes installed

    Bonus reason:
    9. More accurate than the same gun with a metal spring
    (Because of improved shooting characteristics)

    Numbers 2, 3 and 9 are contrary to my understanding of previous reports. I thought the gas springs had a harsher (shorter) firing cycle, just as much recoil and didn't change the accuracy. Are they playing word games, or am I misunderstanding?


  9. B.B.
    The 48 showed up this morning.
    Question about the little plastic cover on the cocking arm release….
    Is it just for protection during shipping? Falls off easily.

    twotalon


  10. B.B.

    Thanks for the reference to Umarex. They're great, and I'm shipping my CP99 Sport off tomorrow. They had a nice touch of Southern hospitality unlike the cavemen of EAA Corp or the Savage assistance which has just encountered civilization.

    I saw a lead story on Yahoo news the other day about the ammo shortage. Apparently, the factories are working 24/7 and still cannot keep up, so there is no creation of an artificial shortage. The usual consumption of 7 billion rounds per year has gone up to 9 billion. No one in the industry has seen anything like this or really understands the cause. I suspect it is a Perfect Storm of economic collapse and a new democratic regime. With the economy starting to turn around by some lights, at least one of the causes may be removed. And, in fact, my Black Hills 69 grain .223 showed up on the Midway site for the first time in a long time. Yippee. I didn't waste any time ordering.

    Matt61



  11. BB,
    I think the one-sized hex head was a nice touch, but I carry a full set (like a pocketknife) when I'm leaving home, for stock screws and the like, so it is not a big deal.

    I have been really impressed with the Leaper's Accushot 1-piece mount, which I finally used on my Glenfield 60 "scope catapult" (the mount was for my 36-2, which is more enjoyable with open sights). If this one is even better at clamping than the Leapers, it ought to be really good.


  12. CowBoyStar Dad / Vince,

    In addition to the 200 series that fit 3/8" or 11mm dovetails BKL also makes a 300 series (for 30mm scopes) and a 400 series for 14mm rails/dovetails. The 400 series don't have the crossbar like the old mounts that were made to fit rifles like the slavia 630/631 but owners of guns with the crossbar rails (old webleys, fwb 124/127 and slavia 630/631) that have used the BKL 400 series swear they don't move.

    kevin



  13. Fused,

    The firing cycle does become smoother with a gas spring, but only if you hold the gun correctly. If you hold it tight, it will feel harsher.

    Less recoil-definitely. But again, you have to hold the gun in the artillery hold.

    More accurate? Perhaps a better way to say it would be "Easier to shoot accurately." The accuracy is in the barrel and doesn't change with the gas spring. But the gun does become easier to shoot accurately because the firing cycle is quicker.

    B.B.


  14. Anyone have an opinion of TruGlo red dot sights (or optics generally)? I want to get a cheap one so that my Dad can shoot my Savage 10FP. His vision is not good enough for a scope or even peep sights.

    Matt61



  15. Uh – what plastic cover on the cocking arm release? Neither my '48 nor my '52 have a release, ya just pull the arm out.

    FWIW, 3/8" != 11mm!!! 7/16" = 11mm, so 3/8" is just about 1/16" smaller. Dunno if it matters with this mount – it looks like those side clamps really don't wanna move much…



  16. twotalon,

    If you're talking about the release button on the opposite side of the cocking arm, it was probably just a cover for shipping as you suspect. Don't remember my new RWS 54 having one on in shipping but that was a long time ago for my memory.

    My release button didn't have a cover and wouldn't have functioned with one.

    You may want to double check with PA tech support though.

    kevin



  17. B.B.
    The litlle plastic thing could be gooped on with a drop of epoxy.

    It's yellow in color and stands out easily from the rest of the gun.

    Shot it a few times with .22 cphp and 16 gr exacts. Dieseling, but no detonation. Not very noisy. Firing stroke feels solid and not twangy. Trigger needs some breaking in….a little rough.

    twotalon.





  18. B.B.,

    I know you're pulling my leg.

    You've forgotten more about airguns than I know. These details are still in your brain they're just locked away in one of the back file cabinets.

    Put something I hope you find of interest in the mail to you yesterday.

    kevin


  19. Matt, I put a couple of Tasco Red Dots on my boys airsoft, which from the photos looks to have come from the same factory as the TruGlo.
    They're fine. I have the high-end Walther on my Nightstalker (2.5x the price), and except for it being a bit brighter due to the 30mm tube (as opposed to the Tasco/TruGlo 25mm tube) I can't see a heck of a lot of difference.
    I'm sure the more expensive Red Dots are better built but if you're not hard on your gear I wouldn't see a problem.
    CowBoyStar Dad


  20. BB, I was thinking more of using two chrono's: one at muzzle and one downrange at the target (armored against stray shots). The ballistics calculator tools are useful as well, but my first thought was to get a rough idea of the velocity loss over range and how many foot-pounds you can expect when you strike your target. Maybe a good blog article would be to calculate, then experiment to see how close the math is to a real-time test (math is exact, but there are lots of variables that still leave minute differences to reality) I know snipers study extensively in what affects a shot, but I'm still curious to see what actually transpires on such a test. JP


  21. JP,

    A Man named Sam Fadala did what you are talking about for his black powder books. At the end of the test, he had destroyed several sets of skyscreens. be sure to cost that into your experiment.

    B.B.


  22. JP,

    The results downrange would be more interesting than you would guess…

    Just discussed for a PCP where BC changed from 0.268 to 0.348 when the muzzle velocity dropped only 30 fps!

    http://www.network54.com/Forum/79537/message/1253695252/Ballistic+coefficient+relationship+to+velocity+…+a+set+of+data+..+trend

    Two chronys? I'd like 6 – one every ten yards from muzzle to 50 yards. It doesn't seem like BCs are all that constant.

    Also vary muzzle speed. Shoot PCP from muzzle velocity at fill pressure to 300 fps or so.

    Also try different guns – BC seems to change…

    Herb



  23. BB,

    You're absolutely right. I left out a zero. The data is for pellets.

    At 895fps BC=0.0268 and when muzzle velocity dropped to 866 fps the BC was 0.0348

    Measurements were made between muzzle and 10 yards.

    Pellet was JSB Exact 15.9 gr


  24. CowBoyStar Dad,

    Thanks for the report. It corresponds with a lot of reviews I've read.

    TwoTalon, trigger rough on the RWS 48, eh? I had supposed that the trigger would really shine. Don't forget the option of tuning. I'm quite the convert myself.

    Matt61


  25. Matt61
    Trigger is smoothing up after only a couple dozen shots.May be a little dirt in there.
    May be short on power. Not getting through a pine board. Crono test tomorrow.
    twotalon




  26. [a rather friendly chap suggested I re-post this question here for better visibility]

    BB

    Thanks so much for the wealth of information here. Unfortunately, I’m experiencing info overload. I’m a budding new air gunner in the market for an air rifle and I’m desperately seeking some advice/recommendations.

    I’m looking for a quality rifle that is going punch paper without remorse and stay around the $300 mark. It needs to hold its own on the rifle range and be fun to shoot at variable ranges (10 – 25 – 50? yards). I don’t have a power plant/action preference (except no PCP or CO2) and I’m not afraid to work so cocking effort isn’t a big concern. Wood stock is preferable. I have some experience shooting but I’m still pretty green so something both forgiving and has room for me to grow into it.

    I’ve considered everything from a Benjamin 397 to a RWS 48 or 52 although the latter are pushing my budget.

    Thanks
    the “Newbie”


  27. Hi BB,
    I'm off subject. Don't see how to ask a random question, but here goes. A "major retailer" sells a Beeman with 2 barrels (.177 and .22). I read that the Lewis & Clark airgun had two barrels. Searching your posts I saw reference to a Mendoza and AirForce air guns as having two barrels. Have there been many airguns that were sold with two or more interchangeable barrels? It seems it would be expensive indecision.
    Dennis from Indy



  28. Newbie,

    Thanks for joining us here. Vince could be correct. You may want to want on your final choice until B.B. finishes the series on the Hammerli Razor.

    In the meantime let me assume from your comments that hunting is not what this gun will be used for rather it will be used only to "punch paper" at up to 50 yards and more likely 10-25 yards if I'm reading your criteria correctly.

    If so, then .177 is a good, inexpensive caliber for target shooting (used exclusively in the Olympics and much preferred in Field Target competitions).

    B.B. made a great suggestion of the Crosman Nitro Piston Short Stroke. B.B. did a multi part series you may want to read about. (Use the search box on the right side of this page and type in "Crosman Nitro Piston Short Stroke"). B.B. tested this in .22 caliber and mentioned the extreme hold sensitivity (that required an advanced technique in the artillery hold) and many reports mention that this gun in .177 is even more hold sensitive. On the plus side this gun only weighs 6.94 lbs., has an adjustable cheek rest and has a trigger that can be adjusted wonderfully well.

    The Benjamin 397 is a classic. Since it's a multi pump and not a single stroke spring gun it's not near as hold sensitive. It's a lightweight gun, accurate, tough to scope and will wear you out pumping in a normal shooting session.

    The RWS 48 I'll let twotalon speak to since it's his latest 8.5 pound acquisition.

    My vote, with what you've shared, is an R7. Yes, a new gun will stretch your budget and it will be pushing the limits of the R7 in wind (not on calm days) to be consistent at 50 yards BUT it's a classic, lightweight, easy to cock, has the infamous rekord trigger, easy to scope, great fit and finish and if you get tired of it you can sell your used gun in a few hours on the airgun classifieds. my two cents.

    kevin


  29. Dennis,

    You came to the right place! This is all about random airgun questions.

    You ask a great questions about airguns that come with two barrels/two calibers.

    You already hit on airforce. The talon and condor have several barrel/caliber options. The beeman RS2 dual caliber comes to mind. The beeman elite X2 as well. Can't overlook the infamous Whiscombe. I've hit the wall mentally.

    Anybody else add to the list?

    kevin


  30. Thanks kevin and vince

    Your are correct that target shooting is my priority.

    I had thought about he NPSS but the aesthetics aren't what I'm looking for but I like the look of both the r7 and the razor. The sound profile on the r7 is listed as low-med which is a bonus for me since i live in the burbs. maybe i can even shoot some in my yard without the cops showing up.

    I'm curious to see the final verdict on the razor and if anyone thinks someone at my meager level would be able to make use of the RWS 52 over either of the others.

    thanks
    newbie


  31. R7 at 50 yards? Color me skeptical. In my experience lower-powered guns, even those that are absolute tack-drivers at 10 yards, suffer considerably at those kinds of distances. My HW30 shoots like a dream at modest distances, but at 60 yards it gets outshot by guns costing 1/2-1/3 the price.


  32. Newbie, the Diana sidelevers (48/52/54) are very accurate and relatively easy to shoot. They balance well enough so that the weight seems less than it really is (to my hands, at least). Really a nice gun.

    If it's over your budget, I might have some information that could help you out. You can contact me at vfblovesnancy@yahoo.com, if you want.


  33. Newbie,

    Vince is the guy to take your que from. He's had an enormous amount of experience with the guns in your parameters. I haven't.

    Having stated that I must say that most of my shooting this summer has been consumed by long range shooting (I'm slowly getting over it). The guns within your stated budget (maybe stretching it a little) I have shot at 50 yards were the benjamin 397 (unscoped. this was done once. fun contest.), gamo cfx royal (4x cheap fixed scope), beeman r7 (tuned with a 4x fixed good scope, beeman ss2), norica krono (leapers 3-9 x 33 ao scope) and a bam b26 (tuned by mm also with leapers 3-9 x 33 ao scope).

    Without wind, with jsb exacts, the 4 of us that shoot regularly can often put pellets from the R7 in 2" at 50 yards. Occasionally I can do better with the bam b26 (scope?) but the majority of the time the R7 shoots the best groups WITH FIXED 4X SCOPE. Pleeaase bear in mind that I'm talking about groups with very little or no wind. If the wind is blowing we don't even try to shoot these guns past 30 yards. Waste of time.

    Newbie, if you want the same platform with a little more power look at the hw50s.

    I don't have any pictures but look here:

    http://www.network54.com/Forum/79537/thread/1228697763/45+Yd+R7+Groups-Express+Shines+Again!+(pic)

    newbie, you admitted you're on information overload and I don't think I'm helping. If so, please disregard.

    kevin

    ps-Vince, love ya like a brother. thanks for always chiming in. I learn something everytime.


  34. Newbie,

    Welcome. Yes, I know the feeling of information overload. It can translate into an impulse to own everything which you have to fight or at least put the brakes on. I come down solidly on the side of the RWS 48. The Benjamin 397 is also very good. But if you are shooting at 50 yards, you will need all 8 pumps which are a drag, especially shooting from a bench.

    The RWS 48 is a fantastic shooting machine, and I believe the sidelever is the easiest non gas/pcp powerplant to work off a bench. As the most frugal of the frugal–downright cheap in fact, I have discovered that pushing the budget a little bit is usually worth it if you are paying for quality, and you are with the RWS 48.

    Matt61



  35. Dennis,

    I don't know where you heard that the Lewis & Clark air rifle had two barrels. I've never heard that. Right now there is some good evidence that they carried a Girandoni repeater.

    Most of the two-barreled guns you have seen are inexpensive. They are either made in China or Mexico.

    The AirForce is made in Texas and uses Lothar Walther barrels that cost about as much as one of the inexpensive two-barreled guns. The Whiscombe that Kevin mentioned is no longer made. Each barrel for it cost more than the two-barreled guns.

    B.B.


  36. Vince, I'll second your opinion of the R7 at 50yds. My Slavia, which is similar in power to the R7 is a tackdriver at 10yds. I really feel that with a proper precision sight and the artillery hold it will rival my 853c.
    And it's still shooting good at 25yds.
    But 50?
    Those 1/2in groups at 25yds spread out to 3 or 4in at much over 100 feet.
    CowBoyStar Dad



  37. Kevin,

    Tom Gore updates his products constantly. No, I haven't seen this iteration, but it is undoubtedly an update of this one:

    http://www.pyramydair.com/s/a/Air_Venturi_Pro_Guide_Spring_Retainer_Fits_RWS_Diana_34_36_38_48_52_54_models_with_TO1_or_TO5_Trigger/2475

    Reported on in this report:

    http://www.pyramydair.com/blog/2008/09/pro-guide-spring-retainer-system-for_24.html

    When I wrote that blog, Gore (the owner of Vortek) redesigned the product while I was writing about it, so I had to scrap what I had done and re-test the thing a second time. I have worked with him for about 12 years now, and this is his M.O.

    I'm sure that what the guys are saying about the new kit is true, but it is an incremental increase over the spring guide PA already sells. I think they will probably carry it, if Gore doesn't change it again.

    B.B.


  38. B.B.,

    I remember the drop in kit you reported on that Pyramyd Air carries.

    The only reason that I brought it to your attention is the buzz (hype) about this "new and improved" kit is so much better. Many of the reviewers claim to have replaced the old kit with the new one. Could very well be hype to enable the reviewer to justify their actions.

    kevin


  39. Kevin,

    There was actually a dead-blow system invented many years ago, but the difficulty of manufacture, plus the cost, was apparently prohibitive. I'm pretty sure these guys are telling it as they see it. The new system is probably very nice.

    You have alerted me to the existence of the new system, and now I will start looking for it.

    B.B.



Leave a Reply

Your email address will not be published.


3 + 7 =

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>