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Ammo Crosman MK-177 multi-pump pneumatic: Part 2

Crosman MK-177 multi-pump pneumatic: Part 2

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1

Crosman MK 177 multi pump pneumatic
Crosman MK-177 is a multi-pump version of FN’s SCAR.

Happy New Year! 2014 promises to be a wonderful year for airguns, and we all will have a lot to celebrate. Edith and I wish all of you a healthy and prosperous New Year.

Lots to cover today, so let’s begin. This is the day we test the velocity of the Crosman MK-177 multi-pump pneumatic.

First things first
There’s a storage compartment in the butt, but Crosman doesn’t tell you how to access it. The black rubber buttpad is just a rubber cover with a lip that goes into a channel on the buttstock. The cover comes off like a jar lid. Don’t try to pry it off with a knife or a screwdriver because you’ll mar the plastic. Instead, grab the whole buttpad sideways and roll it off the butt. It was too difficult to do with my hands at first, so I used a pair of channel-lock pliers and it rolled right off. After 3 times though, I could roll it off at will. Be careful not to crush the plastic buttstock when doing this.

Crosman MK 177 multi pump pneumatic butt storeage
The rubber buttpad is made like a cover and has to be rolled off the butt.

Next, I was wrong when I said the bolt handle is okay on the left side of the gun. Because you have to manually advance the magazine, which is on the right side, having the bolt on the left does make cocking and loading the gun clumsy. However, if you look at where the BB magazine is located (on the right side) Crosman put the cocking handle on the left because they had to. This is something that I think could stand some attention.

Next, I told you the pump handle is hard to pull away from the gun. Several readers agreed with me, but one reader told me to shift my pumping hand so it wasn’t so close to the end of the pump handle. When I did that (held the pump handle in about the middle), the handle easily came away from the rifle and the problem was solved. It does come home with a very loud clack, though.

And, finally, I forgot to mention that when you shoot BBs you have to leave the pellet magazine installed. It doesn’t have to be advanced, but the bolt uses 1 of the 5 pellet slots as a guide to push the BB through when you load a BB.

Crosman MK 177 multi pump pneumatic BB magazine
BBs have been put into the gravity-fed BB magazine and you can see them though the slots cut into the right side of the receiver. The pellet magazine must be installed (but not moved) to guide the BBs into the barrel.

Velocity with Crosman Premier lite pellets
The Crosman Premier lite pellet is a domed lead pellet weighing 7.9 grains. That makes it a medium-weight .177-caliber pellet. Instead of giving you averages for the various numbers of pump strokes, here’s a list of the velocities per pump stroke from 3 to 10 strokes.


After the final shot, I cocked the bolt and fired the gun. No air was exhausted.

Then, I shot 5 shots of Premier lites with 5 pumps each. The average was 499 f.p.s., and the range went from 491 to 503 f.p.s.

Crosman SSP pointed pellet
Next I shot the 4 grain lead-free Crosman SSP pellet. Again, I’ll give a string of velocities as the number of pump strokes increases.


After I fired the last shot, I cocked the bolt and fired the gun again. No air was exhausted. So, I did something that I don’t recommend, just to show what happens. I pumped the rifle 12 strokes and achieved a velocity of 762 f.p.s. with this lightweight pellet. Then, I cocked again and fired. No air was exhausted.

You can see that the velocity increases start to get smaller after 6 pump strokes. Those last few strokes (9 and 10) don’t really add a lot more velocity, making them hardly worth the extra effort.

Steel BBs
Next, I filled the BB magazine with Crosman Copperhead BBs and did the same test.


Following this test, I pumped the rifle 5 times for each of 5 shots and got an average velocity of 564 f.p.s. The low was 560, and the high was 567 f.p.s.

It seems obvious that BBs will go faster on fewer pump strokes; but when the number of strokes increases, the lead-free pellet goes even faster. It’s more than a full grain lighter; and, of course, it seals the bore better than the BB.

The last thing I’ll comment on is the trigger. I said I thought it was a good one in Part 1. Well, that was confirmed in this test. Though it’s only single-stage and the pull is long, it’s free from creep and is light enough to be a delight. It fires with 2 lbs., 8 ozs. of pressure.

Overall evaluation
So far, I like the rifle a lot. It takes some getting used to — expecially that bolt handle location and finding the proper method of grasping the pump handle so it operates smoothly. I don’t like the loud clack when the pump handle comes home, but I bet a small piece of rubber padding could take care of that rather well.

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.

28 thoughts on “Crosman MK-177 multi-pump pneumatic: Part 2”

    • LOL! Rob, just like I mentioned previously: Every once in a while, it’s nice to encounter something that seems to work better for a leftie :-). In one smooth motion that seems intuitive, I can cock the gun and index the pellet strip with very little waste of motion, but I can see how annoying it would be to a right-handed person.

    • Yes, and it worked!!! I’m a Southpaw and I love my MK-177. Then again, I love my M4-177, too. You know the truth about us lefties is that we are ambidextrous… Safe Shooting!

  1. I found a way on the pump guns I have to keep them quiet when they come home when you pump them.

    Is to hold the hand that pumps the gun close to the end of the handle. Then the hand that is holding the gun I put right behind were the pump handle closes. When you open the handle and start coming home you start to slow down your pump hand and let that hand contact your holding hand. Kind of acts like a cushion.

    We did that when we were kids shooting pest birds on the farm to keep our cover so they didn’t hear us.

    Only problem Is the fake magazine is in the way on this gun. Seems like they changed the ergonomics around on this gun. I guess I could adapt after I shot it for a while.

    And that is respectable fps.

    And Happy New Year to all.

  2. How much could someone charge for a PCP conversion like Dennis did on the 2100?
    This rifle is currently 20$ more than the 2100 and would look a lot better to me, plus it’s a repeater, which I love.

    Happy new year to all and may 2014 be better for you than 2013 was (I sure hope it is for me because 2013 was mostly crappy).


  3. To quiet the pump I have used the small felt stick on pads that they sell for nic nac feet. They are very thin and seem to stay put without sticking both surfaces together.
    On a related note I really love pump guns and wish someone would build a real true quality gun with a good trigger and nice stock. I know Daystate did it but they are scarce as hens teeth and they weighed a ton. A Blue Streak meets HW would be very appealing, good barrel, nice adjustable trigger and well proportioned stock all with variable power.

      • Kevin,
        I had not. I did not even know about it until just now. After doing a search and a little reading it sounds almost exactly what I was looking for. The only 2 problems I see are that it fires at full power or what ever you have it set for and cant vary the power by just varying the number of pumps, which is a trade off I guess for the repeater function and I could probably live with that but the price is a bit of a problem. I know you pay for quality but my AA Pro Target was $600 less. If they get the price down to the 1K mark it would be in my cabinet.

        • Sam,

          You need to look at the NEW FX Independence. Some significant changes have been made. Among them are a carbine/bullpup option which results in the FX Independence being a compact rifle with a total length of 29.5″.

          The FX power wheel has been added to the Independence which gives you 3 distinct power settings (low, medium and high) very similar to the power wheel you find on the FX Cyclone. The Independence is offered in .22, .25 or 30 caliber and on the high setting generates 30fpe, 46fpe and 75fpe respectively.

          Can’t help you on the price but when you consider the Independence comes with a built in hpa pump it’s a bargain in many peoples minds.


    • Sam,

      The Tim McMurray / Mac 1 steroid treatment on a Benjamin 392 would give you variable power up to about 30 foot lbs., and the trigger mod that is standard with the mod makes the trigger very, very nice. The only thing that you would still not have is a world-class barrel, but the Benji barrel is decent nonetheless.

      I think you could get about five of those from Tim for the same price as one FX Independence or Indy.


  4. Happy New Year to you and Edith, and everyone here in the peanut gallery!

    Crosman claims this gun “features new valve technology combining lower pumping force with higher velocities,” but the results of your test show otherwise. I could’nt care less about the bogus velocity claims, but I am curious about the effort required to pump it-I don’t know if you’ve pumped a 760 lately but is there a difference at all?

  5. I have artritic fingers so can’t get the finger pressure to remove that butt pad. So I cut a notch in the bottom of the buttpad so I have something to get hold of to gain access to the storage area. I found this works better than having to pry and twist the piece. Seems like the shot velocities aren’t exactly as advertised either. It’s kind of a disappointing gun for all the looks of it.

  6. B.B.,

    At last a rifle with the cocking bolt on the correct side! To this lefty, the MK-77 cocks like a dream! I believe this is the first ever airgun of any kind to have the cocking handle come standard on the correct side.

    I bought one of these a while back when Pyramyd AIR had the black ones on sale for a really good discount. I do like futuristic looking guns, but I am not deeply ito most contemporary tactical designs. I was drawn to this one; however, because to me it looks like something space soldiers might use against aggressive aliens in a sci-fi movie.

    I wonder if a better use than storage for the hollow buttstock might be a good dose of expanding foam. The gun is very light in a not-so-good way, and it has the creaks and rattles associated with hollow styrene.

    Also, while in time I also discovered the trick of releasing the pump handle with a middle grip, of course it is still advisable to move one’s grip back toward the trigger for maximum leverage. The structure of the rifle does not allow as much leverage as, say, the Daisy 880, which is a dream to pump.

    I intend to cut off the useless fake magazine and affix some sort of pump handle extension that conforms to the underside of the rifle and ends just in front of the trigger guard. My guess is pumping effort could be cut in half by doing this.

    OR perhaps this is a good candidate for a low-pressure PCP conversion!


    • Michael,

      The best way to pump this gun is to grab the handle up to within 2 inches of the Picatinny rail, but once it pops free, roll your hand so just the heel pushes the pump handle in. That way the handle comes out easy and goes in easy, too.

      And no, I don’t think this one is a candidate for any modifications.


      • B.B.,

        I am able to pump it fine until I get into the 9-10 pumps range, where it becomes a bit of a chore because of the shortness of the lever. I can pump it to ten if I want to, but it requires enough effort that I find I do not want to. But give me a long enough lever, and, well, you know the rest.

        I respectfully disagree about the MK-177 as a mod candidate, with the qualifications that I know nothing of either the innards of this gun or of Dennis Quackenbush’s work on the 2100b. But first, the MK-177 is cheap. Second, take a look at all of that space inside the forearm/pump handle. Clear out all of that reinforcing plastic and the pumping linkage and levers, and there would be room for a 9 oz. CO2 bottle or gosh knows how large of an HPA cylinder.

        I think the MK-177 could be a mad (mod?) scientist’s dream.


        • I still cant wait for part 2 of the $100 PCP. The fill pressure and fps the gun makes.

          And why wouldn’t this gun be a candidate for a conversion. I haven’t looked at the schematics of the gun. But I would think it could happen if somebody wanted it bad enough.

          Come on BB you got everybody thinking now about power source conversions. 🙂

            • Ditto! (or, x3)
              While we’re at it, why is it so many pumps are required on this type of gun, when pistols like the P1/P3 or Webleys only require 1 or two?
              I deliberately put 100 rounds downrange with my m4-177 @ 10 pumps each and developed Popeye arm. Walked lopsided for the rest of a day. 2 pumps to hit max fps would sure make these things a heckuva lot more fun during extended shooting sessions.

              • I think it has something to do with velocity. For some reason low velocities seem to be acceptable for handguns but not for rifles.
                The Webley Alecto has quite a big pump yet is easy to use on one pump but you can pump it 2 or 3 times (4 if you buy tbe ultra) to get more velocity.

                A single pneuatic would be more interesting to me but a PCP… now THAT would be interesting!


  7. B.B.

    Wish you & Ms. Edith a Very Happy New Year Sir. Thank you for all your time, commitment and vast knowledge so generously given for our immense benefit. I have become a good shot,got a well performing airgun & gained great info on airguns thanks to you. I follow every single article though I don’t comment much. May God Bless you all & keep you in Great Health & may He give you long Life.
    Thanks Again for your great work!!


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