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Education / Training Crosman MAR 177: Part 6

Crosman MAR 177: Part 6

by Tom Gaylord
Writing as B.B. Pelletier

Crosman MAR
The MAR177 from Crosman.

Part 1
Part 2
Part 3
Part 4
Part 5

History of airguns

This report covers:

  • Sight-in
  • First group
  • Qiang Yuan Olympic pellets
  • RWS Hobby
  • JSB Exact RS
  • Discussion
  • Summary

You asked me to back up to 25 yards with the Crosman MAR177 and today is the day I do it. It should prove to be an interesting report.


Because I was using the iron sights that came with the rifle, I skipped the sight-in at 12 feet and went straight to 25 yards. My sight-in pellet was the Air Arms Falcon that was so accurate in the test at 10 meters.

The first shot went two inches high at 25 yards. After seeing that I adjusted the rear sight down 5 clicks. I had adjusted it up the other day for photography when I was exploring its adjustability and writing Part 5.

Dropping 5 clicks dropped the second pellet 8 tenths of an inch, so I was still above the bullseye. I then adjusted the rear sight as low as it would go, which was only another 6 clicks. Then I just shot the remaining 8 pellets without looking through the spotting scope again.

I’m not going to measure this “group” because of the sight adjustments that were made. But I will let you see it.

MAR sight in
The sight-in target was shot from 25 yards with Falcon pellets. The 8 shots in the black were fired with the same sight setting.

Obviously this pellet is hitting too high, and the rear sight is as low as it will go. The only solution is to adjust the front sight higher. I used my new 1/8-inch roll pin punch to adjust the front post up 5 clicks. Remember, adjust the front sight in the direction opposite of how you want the pellet to move.

First group

I shot ten more Falcons after adjusting the front sight up. Ten pellets went into a group that measures 0.793-inches between centers. I pulled the second shot because I was trying to take up the stage one trigger pull and I fired the rifle before I was settled in for the shot. So I am blaming the trigger for that shot. However, even with that I got a decent group at 25 yards with iron sights. But the group is at the bottom of the bull. Apparently the front post adjustment moves the strike of the rounds farther than the rear sight adjustment.

Falcon group
The group of Falcons after adjusting the front post is 10 shots in 0.793-inches at 25 yards. Adjusting the front post up 5 clicks dropped the group to the bottom of the bull.

Qiang Yuan Olympic pellets

Next to be tested were the Qiang Yuan Olympic pellets. These weigh almost a full grain more than the Falcons, so I did not change the sight setting. I did not look at the target while shooting this group and it wasn’t until I walked down to the bullet trap to change the target that I saw what had happened. Ten pellets landed in a round group that measures 0.411-inches between centers. It’s the best group of the test, and I was astonished that the MAR could shoot this well. Five shots landing this tight might be called luck, but ten is something more. Ten shots this tight tell us that with the right pellet the MAR can shoot!

Chinese Olympic group
The MAR177 put ten Qiang Yuan Olympic pellets into 0.411-inches at 25 yards. This is the best group of the test.

After seeing how low on the bull the Chinese pellets hit I adjusted the rear sight up one more click up — making the total rear sight adjustment 6 clicks up.

RWS Hobby

The next pellet I tested was the RWS Hobby that did well at 10 meters. At 25 yards the MAR put 10 of them into a 1.098-inch group. Obviously Hobbys fell off at this distance, as we expect all wadcutters to. Can’t figure out the Qiang Yuan Olympic pellets though!

Hobby group
Then Hobby pellets went into 1.098-inches at 25 yards.

Obviously one click up did not move the shots high enough so I adjusted the rear sight another 2 clicks up. That’s a total of 8 clicks up after I adjusted the front post 5 clicks up.

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JSB Exact RS

The last pellet I tested was the JSB Exact RS. This dome is similar to the Falcon pellet so I thought it might be a good one for the MAR. This time the rifle put 10 pellets into 0.923-inches at 25 yards. This group was a little higher in the bull but it was also a trifle off to the left.

RS group
The MAR shot 10 JSB Exact RS pellets into 0.923-inch group at 25 yards.


The MAR177 shot better at 25 yards than I expected — at least for one pellet. The sights allow for precise shot placement because there are elevation adjustments front and rear.

I think I will call this test finished and move on to mount a scope on the MAR. That should give us a good look at the potential accuracy.

I still don’t care for the trigger. I think it was the reason for my thrown shot on the first group and I have to get accustomed to it every time I shoot the rifle.


The Crosman MAR177 is performing as it was designed to. It’s a top-flight pellet gun upper for the AR-15. It fits any AR-15 receiver that has standard-sized 0.154-inch pins, as opposed to the larger 0.171-inch Colt-style assembly pins.

It is unregulated, and handles air sparingly, getting up to 160 shots on a fill with 145 of them differing in velocity by just 24 f.p.s. The 10-shot rotary magazine works well, as long as the rifle is level when cocked. If the muzzle is elevated there can be a jam or a failure to feed.

Crosman built the MAR with the best of materials. They made it to shine, and shine it does. I am excited to shoot it with a scope, but I believe I’ll give you a break before I do.

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.

93 thoughts on “Crosman MAR 177: Part 6”

  1. Looks like you got a keeper there especially with the Yuan pellet.
    If you decide to keep it, it will be time to assemble a dedicated lower, and find a trigger you like better.

    Another rabbit hole for us to follow!


  2. B.B.,

    Given the accuracy (aided by the Lothar Walther barrel) and the multiple shot capability, I just wonder why Marketing failed in its job to promote this gun for the AR platform owners? Seems like a no brainer. What was different at the time? PCPs were already on the market for some time. Cost should not have been much of an objection to that market segment. Yet this model languished in sales. I hope TCFKAC does a better job the next time around.


  3. For once Siraniko and I agree.
    With so many AR owners out there I and very surprised this is/was not a best seller.
    Have a nice weekend all.
    Stay safe, stay sane,


  4. Siraniko and Yogi, and others as well,

    The average AR dude and dudette no nothing of airguns. To most people when you say airgun they think of a Daisy bb gun, a Crosman 760 or just maybe a Benjamin 397. I know this because once upon a time that is what I thought. Then the internet arrived, thanks to what’s his name, and I discovered a whole new world.

    Even then, if it had not been for the fact that I had lost interest in powder burners, I may not have explored this world. Many believe airguns are for children. Many believe that children learn the basics of shooting with them and then graduate to powder burners.

    For an AR owner to want to buy one of these, they would first need to have explored this world further than their childhood. Then they would have to overlook the cost. A complete AR can be had for less. They are not likely going to use a hand pump, so they would need a different source for air which translates to more cost.

    Then most of them are going to be disappointed with the power level. They are going to expect this thing to drop a deer at one hundred yards. Even if they accept the power level, the accuracy is going to be terrible because their trigger is.

    “Only ten shots per magazine? What do you mean it is not semiautomatic or selective fire? Ten meters?! I can hit a deer between the eyes forty-seven miles away with my AR!…Yadayadayada.”

    Maybe the time was wrong. I seriously doubt that TCFKAC will go there again. Look at the new Rogue.

    • RR,

      All good points. Maybe they can sell the military a bunch to use as (initial) trainers = high volume sales. For civilian use,.. maybe someone that is into PCP’s already and has some extra lowers lying about. If just wanting to do some lower cost plinking,.. I think I would go the .22 RF route in a direct copy to whatever my larger caliber choice would be (2 complete and separate firearms).

      If regular access to a rifle range (or safe rural land) is an issue, well then,…. this is pricey option.

      Good Day all,………. Chris

      • Chris,

        Dream on my friend. It is not going to happen. They are not going to bring Lloyd’s Rogue back either. There is a much better chance that they will learn how to make a decent sproinger trigger and put forth the expenditure to install them.

      • Chris,

        My brother-in-law Bob. who signs in as B-I-L, shot his .22 rimfire upper recently. He put his shots into about 4 inches at 25 yards. Then he shot his Umarex Synergis and put 12 shots into way less than a half inch at the same 25 yards.

        That’s what a .22 rimfire upper can do. Maybe some shooters have a better experience to share?

        • The .22 conversions for those that aren’t too familiar replace the bolt carrier group with a chamber insert, and bolt carrier that functions with .22lr, it is held in position by the close chamber tolerances, and some spring pressure from the buffer assembly.
          But the adapter does not reciprocate like the .223 bolt carrier does when fired.

          I have been running a CMMG conversion in a dedicated upper since 2011.
          A shooting buddy sold me the 5.56 upper very cheap, as he had been having problems with it sticking cases, and when he handed it to me, it had a live round stuck in the chamber.

          After clearing the live round, i found several chamber imperfections, I decided it would never fire another 5.56 round while I owned it, and built it into a .22 rimfire.
          I had the caliber marking crossed out, and barrel restamped to read .22 LR ONLY.

          Just like pellets, depending on the ammo, and twist rate of the barrel you get better or worse groups. But 2 inches at 25 yards was the average i could maintain with 40gr CCI standard velocity, and ELEY 40 gr match ammo.

          A few years ago, friend that works at CMMG sent me a upgrade that replaces the brass part of the rear of the chamber insert, asked me to test it and abuse it.

          The upgrade is now called ECL (Enhanced Chamber Lock) it is a set of locking lugs that rotate into the barrel extension, to lock the adapter to the barrel.

          That coupled with the dedicated lower i built, that uses the buffer and spring to push the adapter forward under more than normal spring pressure. (i removed the buffer retaining pin allwoing it to move forward more)

          Those 2 things, brought the group size down to 1/2-3/4 inch at 25 yards with the same ammo.
          I can live with that.

          Below is a photo that shows the 3 most common .22 adapter inserts, steel, brass, and ECL, with the ECL on the left.


    • As Ridge Runner so aptly put it, the average AR dude or dudette had little or no interest in my air guns at the range. They would be more interested in another upper in 300 Blackout or 6.5 Creedmoor.


      • Brent,

        I am certain you can remember the .50 Beowulf. Now that was an abomination.

        6.5 Creedmoor? Really? .22-250, .243, 7mm-08, 7.62 NATO. I guess they just had to put a .25 caliber in there.

        Now as for the .300 Blackout, I could see that with a light projectile going supersonic. Or better yet, .25. Anything more than a teenie .223.

    • RR hit it square on the head. My cohorts at the range would have no interest in a BB gun upper for their AR and that they could buy another Glock for the money. And at work, my fellow coworkers with ARs seem to have them just to say they have them. They like to talk guns and shooting, but they don’t actually make time or prioritize their spending to support it.

      I thought these MAR177s were originally developed for a proposed new category of airgun competition? Something like National Match Service Rifle airgun?

  5. BB,

    This may sound stupid,….. but is there (nothing) in the training/simulation world that uses a laser-tag type format?

    I am (not) talking about hitting minute of opponent from 10 feet as in skirmish games,…. but rather something that can teach hold/steady/aim/drop? at 100 + yards. Something that would require you to aim well enough to get a hit within 4″ at 200 yards?


    • Chris
      I know I messed with it out at a 100 yards and other distances. I even used my I phone adapter at the time and my daughter’s were involved. I used my good green laser on a gun with a scope also. I sighted with the scope at the target and used the whole and half mildots to see what points the laser was at when the shot hit the target. Then seen what mildot hold over I needed at that distance with the scope. I could then aim with the laser in the scope and hit a target.

      Is that kind of what you mean.

      • GF1,

        I am not sure what I am asking,… to be honest. Lack of any reply (other than you) would indicate nothing in laser based training exist. I find that hard to believe.

        Let me (try) re-word this,………… let’s say you have a cartridge that has a laser in it. Then,… pulling the trigger activates the laser. UNTIL the point you pull the trigger,…. there is NO laser. So,… in theory,… you would have to be trained, steady, sighted in, on target, etc.,……….. or otherwise when you pull the trigger (laser activates),.. you either miss or hit. 1 time trigger pull.

        Since a laser is straight,…. I am not sure how you could simulate hold over and long distance ,…. like 500 yards. Maybe not a laser,… but something else,… I do not know.

        I will have to sleep on it and think some more on the topic. I was hoping Shootski might chime in as he seems to know just a “wee bit” on what the military is up to.

        There has to be something other than turning a firearm into a glorified pellet gun to simulate/train. Something that mimics the use,… without firing a shot,… of anything.

        Confused?,………… Chris 😉

        • Chris
          That would be easy to do what your saying.

          But that wouldn’t train anybody anything. Well I shouldn’t say that. What your talking about would teach follow through of the shot. What I’m talking about would train follow through of impact.

          Your forgeting about ballistics. What I talked about included ballistics.

          See what I mean about the differences. Or are you looking for something else.

          • GF1,

            I think Chris is thinking of a very sophisticated version of laser tag.


            There are several issues with this, the two major ones being cost and fragility.

            Train them as best you can, send them off to war and give them live targets that shoot back. If they survive, they’ll figure it out.

            • RR
              Plus if your pointing a good laser at some one that means they can see where you are too. I’ll take a rifle with open sights or a scope depending on what kind of combat I was doing.

                • RR
                  Maybe there is a simpler answer to Chris’s question.

                  Maybe a laser bore sighter could be used with a electric pressure switch attached behind the trigger that would contact a adjustable trigger stop. Or even a laser set up that way. It would only be good for one sight in distance.

                  Ballistic holds would have to be thrown out the door though.

        • Chris and GF1,

          Once upon a time the U.S. military did indeed play laser tag. As most firefights occur at 50 yards or less, ballistics was not an issue.

          Robustness of the equipment and cost were the main issues. You give a rock to a soldier and he is going to break it. The cost was incredible, most especially since they did try to make these soldier proof.

          They went back to training with blanks and live rounds.

          • RR
            When I started in the machine shop trade back in the early 80’s we made more target practice rounds than live rounds.

            Don’t know about now days but that should tell something about how they use to train anyway.

    • Chris USA,

      It is counter productive for most soldiers since as has been pointed out by others that most engagements require point and shoot level skills at best. So it is cheaper to train the specialized rifle shooters with the real thing. Typically taking into account Internal Ballistics (Cold Bore) External Ballistics (you know all the environmental stuff added to the Physics) that would take a heavy duty computer to scan the 3D environment and positions and then drop all the changing dope into it and compute the solution every time the trigger gets pulled. Maybe a SEAL could carry the batteries to make that all work for say 12 minutes…but not the weapon!



  6. Chris USA ,

    The problem with the military using something like this is LEAD . I am not a fan of lead free pellets . In lower powered guns I have seen them not fire or get stuck in the barrel ( mostly SSP pistols ) . There should be sufficient energy for the MAR . Another factor is the KISS principle , these will be used by 18 year old recruits who have never shot a gun , as we know PCPs are for enthusiasts not greenhorns. The reason the National Guard in Ohio shut down all the indoor ranges was the lead issue . They trained with conversion units in the M16 rifles .

    Gene Salvino

      • B.B,
        In part 4 you used Sig Match Ballistic Alloy pellets which are lead free. They seem to no longer be available, and are not shown on the Sig Sauer website. Many of the other lead free pellets are on back order. – Don

        • It sounds like they are very popular and the manufacturers cannot keep up with orders or they cost so much that orders are not high enough to justify continued runs.

  7. BB ,

    I was just curious , I was never able to test one here . I only did one warranty repair on a MAR , I have no idea how many we sold though . Great idea , I hope it gets resurrected.

  8. BB

    I too am curious about the QYT pellets at 25 yards. I have not had much luck with these wadcutters except at 10 meters which of course is what they are designed to do. Guess I need to give them a try. I assume you were shooting outside. The wind must have been nil. That is quite a group and with iron sights and a difficult trigger!


      • Deck

        Oh to have a wind free 25 yard range! But you should have it for certain. I tried Qiang Yaun Training pellets at 25 yards today in a HyScore (Diana 35). First 5 pellets scored .32″ which got me way too excited I reckon, the next 5 went every whichaway to 1.21″.


          • Chris USA

            Yep for sure. I don’t recall ever seeing a group quite like it. No other variables involved or so I thought. After 5 shots I just knew I had found a world beater in the QYT pellet at 25 yards. My HyScore using some pellet types is consistent for 1/2″ to 3/4″ 10 shot groups at 25 yds. Got it at the Hickory airgun show last fall. Cocks almost as easy as a HW30s.


            • Deck,

              What day were you there, Friday or Saturday? Fred DPRoNJ was there on Friday and picked up a Walther LP53 and I was there Saturday and picked up a Predom and a UTG.



              • RR

                I was at Hickory on Saturday. I also picked up a Crosman 160 with the Crosman S331 aperture. It is about as accurate as the HyScore at 25 yards but is a bit loud for my backyard. No complaints yet from neighbors but I don’t shoot it much.

                Do you like the Bug Buster?


                • Deck,

                  I personally consider it the best BugBuster yet. I know many of them have the light system on them, but I never use it mostly because the reticle is so huge. Now if they went to a fine glass etched reticle, I might want the light.

                  I know, UTG is supposed to be bringing out a new line of BugBusters with glass etched reticles, however they are going to be 30mm tubes, side focus, yadayadayada… They may likely be the SWAT Compact with a closer focus. I guess that is OK, but I have a couple of those and they are a good size scope. I like the small, light, compact BugBusters.

                  Now this is my favoritest airgun woods scope.


                  Both of these scopes have earned the coveted 3R rating, but the Hawke will not stand up to uber magnum sproingers.

                  Ooh,ooh,ooh… I just discovered that Leapers is bringing out a 3-9X32 just like the 3-12X32 they brought out last year.



  9. Howdy all,
    I have always been more partial to a nice old cowboy gun, a lever-action rifle, rather than an AR.
    Although, the being said, I don’t know how many recall the old cowboy ad for the Thompson Submachine Gun.
    Note the really furry chaps on that cowboy, hahaha! =)~
    Wishing a nice weekend to everyone,

    • Interesting poster! I have never seen a ‘cowboy’ before using a Tommy Gun.

      By the way, the advertised rate of fire for the M1919 was a staggering 1,500 rpm as can be seen in the ad. I have no personal experience but I must assume that it was not easy to control in spite of its weight. The rate was quickly lowered to about 800 rpm in the M1921 and by WWII it had been reduced even further to 600 rpm.


      • Henry,

        They are very easy to control, even in the “grease gun” types. The .45 ACP is a heavy recoiling pistol, but is real easy to handle in carbine form. Also, with the longer barrel, the pistol round achieves slightly higher velocities. It is an extremely deadly weapon out to about 100 yards.

        It is an effective enough round that the MP5 is issued in .45 ACP.

        • Henry & RidgeRunner,
          I’m having trouble finding an article on google to back it up, but I once read a book about gangsters that said one of them (I thought it was Al Capone) practiced with his Thompson till he could hit a shoot a row of walnuts off a fence…that’s pretty good control. =>
          Take care & stay safe,

          • Dave,

            I would not be surprised. That pistol round in a carbine, most especially a heavy Thompson has almost no noticeable recoil. You will also note the sharp angle of the grips will encourage your hands to “push” down on the weapon as it recoils. The P08, the Glock and others employ a similar design. You will also notice the muzzle brake has slots on the top to use the muzzle blast to help reduce the muzzle rise.

            I have seen films of Marines in WWII using Thompsons in the jungles. There is no muzzle rise.

    • Dave
      Cool ad.

      And maybe its winter time where that cowboy is at. Maybe that’s why those chaps.

      Or maybe like some feathers and fur on some birds and animals. Maybe it will stop or slow down a pistol bullet when its fired at a longer distance then intended. But then I wonder what the shirt is he’s wearing. Maybe its multiple layered leather. Hmm a first bullet proof suit and we didn’t even know it existed.

      • GF1,

        There was a benefit to the sheepskin chaps I don’t remember fore sure but some of the benefits were warmer, shed water and were quiet.

        I ordered one of the Chinese hpa pumps. It will be delivered next week. How is yours working? Is a 5 gal bucket enough to keep it cool for a 20 minute run? Or would you suggest a shorter run? I am thinking about a small radiator with a small fan instead of a bucket. I also plan on using antifreeze to reduce corrosion. It seems like most of the bad reviews are from folks that don’t know how to baby stuff.

        My Crosman/Sheridan 2260 is breaking in nicely. Getting around 1/2 inch 10 shot groups at 25 yds with JSB 18.13 gr pellets. 50 shots and the pressure gage barely moves.


        • Don
          Probably easier to move in the sheepskin chaps than the leather ones too.

          And just got to ask. Why did you order a chinese compressors. And I hope you ordered the one with all the hard lines coming from it. My second one has all the extra stuff on it. It’s a much better compressor. I did some research before I got my second one and there is suppose to be a more quality one than the other. They are suppose to come from the same factory. The lower quality ones are like regects but sell for the same price.

          And who is to believe. All I know is my Yong Hen Air pump as it is labeled is a real good compressor so far.

          And I dont know if they are meant for long runs. But I could be wrong. I can say that mine stays cool filling a gun. Filling the biggest reservoir gun only see’s about a 10° celcius increase in temprature.

          I myself think it could fill a small 90 cubic inch buddy bottle. A radiator or as we call them at work a heat exchanger that uses glycol would be very effective at cooling if you did extended pump run times.

          And nice with your 2260.

          • GF1,

            I think mine has hard lines, they look like aluminum or steel in the picture. Maybe less than 10 minutes on a single run would be better.

            You seemed to have good luck with yours and it looks to perform better than the other ones under $1000. So as long as it holds up I will be happy. Mine says Yong Heng on the side. At the cost it was worth a chance.

          • GF1,

            You had good luck with your compressor so I decided to give it a shot. I think mine has hard lines they look like aluminum or steel. Maybe 10 minutes max run will be better. The pictur of mine says Yong Heng on the side. Hope it is one of the good ones.

            At the price I felt it was worth a chance. It seems to perform better than most of the one under $1000. Time will tell.


            • Don
              I have been thinking about getting a buddy bottle to have full incase the power goes out or something. I think the Yong Heng would fill it. Maybe would take cooling sessions. Don’t know.

              As far as filling guns go. It has worked flawless. It does what I want from it.

              • GF1,

                I got a deal on two large carbon fiber tanks. My buddy at the air gun shop fills them for 5 or 10 bucks if I bring in some garden veggies or citrus. The two tanks last me a long time so the compressor is mostly a backup. The tanks are very handy. If you get a tank I would make sure it can handle 4,500 psi. Otherwise you don’t get a full fill after a couple of uses on the tank.


                • Benji-Don,

                  Do you cascade the tanks?
                  With the price of these Im beginning to think about adding a compressor into my cascade. That will allow me to get way more air out of my two big tanks before they need to get refilled. It will also ensure i only need to run the compressor for short run times. Might even be logical to get a small 4,500psi/300bar tank to top off to max fill. Especially since the future looks like 4,500/300 gun fills will become much more common.


                  • Shootski,

                    I don’t exactly cascade my tanks. I have a few guns that fill to 2000 psi. The rest fill to 3000 so I can go quite a while on two 4500 psi tanks.

                    I also shoot multi-pumps, CO2, and single stroke pneumatics more than half the time. So my hpa use is not great.

                    If you have guns that fill to the same pressure as your tanks cascade is a good way to stretch the air out.


  10. Hi. New guy here. I realize this is a very old thread but maybe someone can help me??
    I finally found one of these ….. used but with the box & original paperwork …. only the carry handle is missing.
    First time at the range …. I cannot get it to zero. It is shooting low & left even with the elevation & windage at max!

    Elevation first
    I think there may be a velocity issue???? I had a couple of pellets that didn’t exit the barrel even though it is clean & lubed. [Ez-Ox]
    I don’t see any velocity adjustment in the manual …. so any direction would be helpful.

    Windage ……. I’m going to put a laser bore sight on it to see where its shooting. I’ll check the locations of the front & rear sights first. Again any direction would be helpful.

    Thanks in advance

    • New guy,

      Oil your pump piston head. The AIR17 is a multi-pneumatic and by now, as old as it is, the pump cup has hardened. It isn’t pumping much air.

      Oil it with automatic transmission fluid stop leak. Read these reports:



      If they don’t work your airgun may need to be resealed. This man should be able to help:

      Rick Willnecker in PA. Contact him at http://www.airgunshop.net/ or email airgunshop@aol.com or call 717-382-1481.


      • Hey. Thanks for the quick response!

        As Benji-Don replied below I have a Crossman MAR-177 [ although I call it my AiR-15 just to mess with the libs]

        I run an injection molding shop so I’m very familiar with hydraulics, o-rings & “stop leak” “swells”.

        Is there an exploded diagram of this item anywhere???

        • 74,

          You want an exploded isometric drawing for the MAR? I don’t know where to find it, but it has to exist. Crosman made drawings, didn’t they?

          DON’T use the stop leak on this rifle. oil, in the presence of oxygen, tends to explode.

          Please answer the two questions I asked you.


      • New guy,

        As Benji-Don said, I missed what you were saying entirely.

        What you have is a MAR17. That is precharged pneumatic. First — STOP lubricating your rifle with anything except silicone chamber oil.



        What pressure have you filled the rifle? How long does it hold a charge?

        Until we know these things there isn’t much to say.


        • Silicone oil ONLY, got it! Ordering some now.

          I filled it to 3000 psi. Took about 20 shots, pressure dropped to 2500.

          I got home & depressurized it. I didn’t really notice if it had dropped further???

          I’ll fill it up again tonight & track the leak down. How long can I leave it pressurized??

          Thanks again!

          • Airgunner74,

            Thanks. You filled it correctly and it held air as it should. Now I’d like to know how long it will hold a charge. If you full to 3000 is it still close to that a day later. It can lose 50 psi from the heat generated during the fill. More indicates a slow leak.

            The part about pellets not exiting the bore is puzzling. I think your barrel needs cleaning. That’s a .177 brass or bronze bore brush with JB non-embedding Bore Cleaning Compound. You can clean from the muzzle but be extra careful around the muzzle itself.

            As for pellets, shoot pure lead pellets. Crosman Premiers are hardened with antimony and aren’t good in low-powered airguns like this one. RWS and H&N wadcutters are probably best for your rifle.

            Keep talking to me. I have wanted to get my MAR177 back up and shooting and may use you as my excuse.


            • So far its been 8 hours & no loss of pressure.
              I ordered some .177 brushes & mops.
              Forgot to order the cleaning compound … damn!

              I have been using the Crossman premier domed pellets .177HB 10.5 gr

              I also ordered a .17 laser bore sight ….. the one I have only goes down to .22

              I guess I haven’t done anything right so far!

              • Ok so after 22 hrs there is no noticeable pressure loss on the gauge …. I guess that’s a good sign??

                Also using a laser bore sighter at approx 10 yards the “dot” is on center …. a little low on the front sight. Rear sight adjusted to “z” … all the way down.

                I can set up a 25 yd range at work …. and bring my front sight adjustment tool & my Tipton gun vise.

                Lube, pellets & bore cleaner all on order too

                Doesn’t explain why I was shooting so far left???

                One other note … when I got it the rear sight was at maximum elevation & max windage to the right. I guess the previous owner had the same issues???

            • Thank you Don! That was very helpful.
              Is there a way to DM other members of this group??
              I’m still waiting to receive the bore cleaner & bore brushes before trying again.
              Thx again

              • 74,
                This is an old report, most folks won’t see it unless they are using an RSS reader. If you comment on the current days report thousands will see it. Not sure what you mean DM? I can be pretty dense.

                • Lol …. old & dense …. you just described ME! …. Lmao
                  DM= direct message, private conversation etc.
                  As I said I’m old & dense …. how do I get on the current days report?
                  I wanted to do all the things Tom suggested before looking for further advice anyway.

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