Springfield Armory M1A Underlever Pellet Rifle: Part 4

by Tom Gaylord
Writing as B.B. Pelletier

M1A
Springfield Armory M1A.

Part 1
Part 2
Part 3

This report covers:

  • The test
  • Sight in
  • JSB Exact Jumbo Heavy
  • Air Arms Diabolo Field Heavy
  • RWS Hobby
  • Accuracy with all pellets
  • H&N Sniper Magnum 
  • Discussion
  • Air Arms 10-shot group
  • Boxing the target
  • Summary

Today we begin looking at the accuracy of the Springfield Armory M1A underlever pellet rifle. Today I will shoot with the sights that came on the rifle. There is a lot to do so let’s get started.

The test

I shot the rifle off a rest from 10 meters. I used an artillery hold because this rifle is powerful and does move around when it fires. I shot 5-shot groups so I could test more pellets and do more tests, as you will see.

Sight in

It took nine shots to sight in the rifle. It was initially shooting low and to the left so I had to bring it up several inches and also about an inch to the right. The manual shows using a center hold on your target which is appropriate for shooting at personnel with a military rifle. This is a pellet version of a battle rifle after all. But for shooting at bullseye targets a 6 o’clock hold is far more precise. So that’s what I did.

JSB Exact Jumbo Heavy

The first pellet I tested was the 18.3-grain JSB Exact Jumbo Heavy. Five went into 0.417-inches at 10 meters. Not too shabby!

JSB Jumbo group
Five JSB Jumbo Heavy pellets went into this 0.417-inch group at 10 meters.

Air Arms Diabolo Field Heavy

The second pellet to be tested was the Air Arms Diabolo Field Heavy. Although it looks like the JSB I just shot and weighs pretty close to the same, this pellet usually performs much differently. And it did this time. The first shot of five went just to the right of center and below the 10-ring, but the succeeding four went into a 0.206-inch group to the left of that. All five shots are in a 0.469-inch group.

Although this group is larger than the first one, those last four shots convinced me that this pellet is more accurate than the JSB.

M1A AA group
Five Air Arms Heavy domes went into 0.469-inches at 10 meters, with 4 in 0.206-inches.

RWS Hobby

The third pellet I tried was the RWS Hobby wadcutter. Although I didn’t adjust the sights, these pellets landed almost one inch higher on target at 10 meters. Five Hobbys went into 0.414-inches at 10 meters. And that result leads me to state something that should be obvious by this time.

M1A Hobby group
Five RWS Hobbys went into this 0.414-inch group at 10 meters.

Accuracy with all pellets

The thing you should have noticed it that all these pellets are giving similar results. The M1A is accurate and it seems not to matter much which pellet is used. Let’s look at one more pellet before we move on.

H&N Sniper Magnum 

The last pellet I will test is the 18-grain Sniper Magnum dome from H&N. It went to almost the same place as the other two 18-grain pellets and five of these landed in a group that measures 0.469-inches between centers. You see? All four of these pellets are performing about the same. This M1A is both accurate and consistent.

M1A Sniper group
Five H&N Sniper Magnum pellets made this 0.469-inch group at 10 meters.

Discussion

I was hoping the M1A would be accurate, and it is. Even though it is a replica battle rifle, it is also a tremendous value in a spring-piston pellet rifle. Yes the shooter will have to accept the envelope of the M14 rifle, but hidden inside is the best springer value on the market!

But there is more to test today. I selected the pellet I thought to be the most accurate and shot ten of them at another target.

Air Arms 10-shot group

This time I adjusted the rear peep up three clicks and shot 10 Air Arms Diabolo Field Heavy domes. They went into 0.741-inches at 10 meters. 

M1A AA 10-shot group
After adjusting the peep sight up three clicks 10 Air Arms Heavy domes went into 0.741-inches at 10 meters.

Boxing the target

I told you in Part 3 that I was going to do this, and, given the results, I’m glad I did. Boxing the target means adjusting the rear sight in a precise way to see whether it moves the groups by the same amount every time.

Boxing the target means shooting five groups. By adjusting the rear sight after each group, you make 4 groups in a square or box pattern. You walk the groups around the corners of a box. The last group lands on top of the first.

M1A boxing target
This is how a target should look if the rear sight adjusts perfectly every time when the target is boxed.

The first time I tried to box the target with the M1A the elevation worked fine but the windage adjustment didn’t. It was apparently adjusted as far to the right as it would go. What I got was two groups, one high and the other low.

On the second try I moved the windage adjustment to the left and I got success on the lower groups but not on the high ones. Here is what the target looked like. These are three-shot groups, but the higher group has three times three shots.

M1A BOXED TARGET
The M1A sight adjusted well when the rear sight was lowered but when it was set high the groups printed together. There are 9 pellets in the top group.

What does this mean? It means the rear peep on this M1A pellet rifle isn’t as precise when the sight goes too high or too far to the right. The sight does adjust — just not with the precision of other peep sights when you get to the end of its adjustment range. It’s not a fatal flaw but it is one to bear in mind.

Summary

The M1A is accurate — today’s test demonstrates that. The peep sight becomes less precise when it gets near its limits of elevation or right adjustment.

So far the M1A shows good power, good accuracy and a nice, useable trigger. The next step will be to mount an optical sight on the scope base and see what happens.

75 thoughts on “Springfield Armory M1A Underlever Pellet Rifle: Part 4


  1. B.B.,

    Looks like the weight of this rifle (nearly 10 pounds) greatly assists in its accuracy. Seems like the sights (whether iron or glass) will be the one holding this rifle back. Sure wish that front sight was adjustable.

    Siraniko



  2. Great accuracy and consistency. Looking forward to the scope tests. I would advise tightening the mount after every shot for awhile. I’ve had two of those SA mounts on M1As in the past. One finally took a ‘set’ and stayed tight. One did not and was replaced.


  3. BB,

    For a replica, this is awesome. The manufacturer really needs to bring those innards out into the world on their own. It appears they have a real winner on their hands.

    Like Siraniko points out, the sheer mass of this thing does help with the accuracy. I wonder how it would do around seven pounds?


  4. Hank,

    That is one big advantage of living way down south, at least in relation to you. We have had short sleeve weather recently. I can usually get in a little shooting all year long. I have to admit that it is no fun with sweat running in your eyes when you are trying to line your sights up. Our new ceiling fan on the back porch will help.


    • RR,

      Last year the snow came early and this year looks to be a repeat 🙁

      Glad that you are having some decent weather – we had an unseasonably mild spell recently as well. Snowing at the moment (already have 4-5 inches on the ground) and the forecasted temperatures for the next while don’t look to be enough to see bare ground until next March – bummer because I wanted to get some more outdoor work done.

      I am already shifting into “winter mode” with lots of indoor activities planned – by me and for me – my wife bought a sleeve of pellets for the 603 (nice of her) and also 10 gallons of paint to do basement (not so nice LOL!).

      Agree – that M1A chassis in an (adjustable) sport stock could be something real special. Accuracy looks good at 10 meters – it has the power needed, if it could shoot sub 1 inch at 25 or 30 yards to be a very nice hunter/plinker.

      Don’t know if 7 pounds is possible (would be nice if they got the weight down, especially if people are going to scope it) all the extra metal on under-levers and side-levers always adds a lot of weight. I really like my TX200 and the weight give it good stability but I would never consider it a walk-about rifle.

      Hank


      • Hank,

        I finally put together a low pressure airgun valve like we talked about. Sure could have used your lathe. I think the valve is so large and the dwell time one the valve long enough that the pellet velocity is dependent only on the pressure. The tranfer of air from the valve to the barrel may be restricted a little. The probe fits inside the barrel so it is a restriction. My next step is to seal the barrel directly to the valve and see if that makes a difference. I need to figure out a way to plug the transfer port in my Maximus barrel so I can seal it directly to the valve. I don’t want to mess up the barrel if I don’t have to. I think a piece of hose over the barrel and transfer port that will also make the seal my work.

        Here is a link to the pictures in the blog yesterday:

        https://www.pyramydair.com/blog/2020/11/oil-talk-and-no-action/#comment-466491

        I was hooking up to my air compressor in front of the regulator, for consistency it should be after the regulator. I don’t want to adjust my regulator around 120 psi, I think that will damage the regulator. My compressor kicks on around 120 and off around 150 psi.

        Don



          • GF1,

            You have the skills to make it work. I just wanted to show proof of concept.

            If I was going to build an airgun to market it would be a balanced multi-pump based on computer models and then fine tuning with prototypes. I almost have the basic program working I have just been lazy. I do not see any modern multi-pump guns designed from the ground up to be a true efficient multi-pump. The old classics were designed based on experience and trial and error. Fine tuning and testing the limits of all the characteristics of the designs were not possible. The Super Grade was the best that could be done at the time. I have an idea that could make the pumping easier.

            Don


            • Don
              Dont worry about my skills and making it work.

              What I will stress is that it is a good idea.

              A low pressure air gun could be the ticket to getting more air guns in the big box stores.

              It’s like a different phase of air guning.

              I think its a big deal.


              • GF1,

                I agree, but don’t have a desire to turn my hobby into a business. I got close enough to that with fishing and it took the fun out of it.

                I will keep tinkering but it will take me a while to get to a working gun. I don’t have a clear vision all the way to completion.

                Don


                • Don

                  No.

                  What I mean is talk to the right people and get it produced and get your share of the cut.

                  Dont let the politics get in the way.

                  I’m telling ya. Mark me a fool but it should of already happened.

                  The world needs a low pressure pcp air gun.


                  • GF1,

                    I did two more tests today when I took a break from cutting brush along the driveway.

                    I tested some oxygen tubing I have about 20 feet. Hooked it up to 150 psi it seemed to be ok. Not sure how long it may hold the pressure but I think it would be good. It is such a small diameter the stresses are low.

                    I also modified my valve the hook to the valve with no restriction using a piece of fuel hose. I took one shot with the pellet seated using the probe off my valve so it would be comparable. At 145 psi I got 470 fps compared to 436 fps before. My guess is at 150 psi 500 fps is about the limit with the Maximus barrel and the AA Falcon 13.43 gr. pellets. A regulated pressure around 120 psi would be more practicle.

                    I appreciate your confidence in taking this to a company and getting a cut but it is just not my desire.

                    Don


                    • Don
                      And believe me I’m glad you are doing all this work.

                      My time just seems to be well accounted for now days for some reason. I’m happy when I get to kick back and relax and shoot.

                      I have always wanted to make something like you have done.

                      We used tubing at work and shot the media from the parts deburring tumblers. We got really good results considering we used air spray nozzles we had at the shop. And yes I know. What was we doing that for on company time. But it was fun and I was surprised at the results.

                      Still got to say you need to take it somewhere.



          • Hank,

            Great articles by Bob, there is too much to learn out there. I book marked the index.

            My thought is to maximize velocity for now. So I wanted a quick opening valve, a straight inline airflow and a smooth short transition to the barrel with no restrictions. It would be a backyard gun teathered to a shop air compressor with a light hose like folks on oxygen string through the house. With the shop compressor wasting air is not much of a problem. If the whole stock was used as a reservoir and filled with low pressure air pcp style then that would be different and a balanced valve would be needed. I think my valve closes a while after the pellet leaves the barrel. At least that was my plan. I sure could have used your lathe making the valve seat.

            Don



  5. Fred DPRoNJ,

    It is quite possible that is the case. If this is so though, my trigger pull is very consistent. When I was in “the zone”, I could alternate back and forth between the two groups by the placement of my thumb and both 10 shot groups would be under dime size. That was pretty freaky.

    You might also keep in mind that this was a sproinger (Gamo CFX), not a PCP. A very slight change in my “hold” can cause a change in how the sproinger jumps, recoils, vibrates, twists, etc., all of which affects POI.

    I do find it amazing that a sproinger is capable of extreme accuracy, IF you can get everything exactly the same for each shot. Will I see “them” figure it out? Probably not. I am too old.


    • I smell a test coming up! For giggles, the next time you shoot one of your “sproingers”, vary your thumb placement. See if indeed it changes the impact location. This would verify that it’s more your physical anatomy changing the aim point as opposed to the sensitivity of the rifle. Any movement on your part is obviously microscopic given the change in impact on the target. And consistent.

      Fred formerly of the DPRoNJ now happily in GA



        • I have noticed that shooting my Marauder and the Sig ASP 20 from a rest on a cushion that if I don’t concentrate, my trigger pull will move the muzzle! That’s with the trigger on the Sig adjusted as light as it will go (2 lbs +) and the Marauder to a little over 1 lb (I estimate but I don’t have a trigger guage). I’m sure changing my hand position would affect the muzzle movement. No wonder I’m not a world class marksman!

          Fred formerly from the DPRoNJ now Happily in GA


    • RR,

      “I do find it amazing that a sproinger is capable of extreme accuracy, ”

      A FWB 300 is a sproinger and IT IS AMAZING! 🙂

      Any thoughts about a SIG ASP20? I would love to get on in .22!

      Hank



  6. Shootski,

    The AirForce airgun bodies are made from a solid aluminum extrusion. They then “cut away” what they do not want. With the exceptions of the Edge and Texan series, the extrusion is cut very similar in the other models. These two models are much stiffer than the others.

    With AF’s other models you see the high arch of the top sight mount and the lower “bar” is hollowed out for the trigger assembly. This creates a long, open separation between the tank/shoulder stock and the barrel that can flex.

    When I speak of the frame flexing, most people will never notice it. We are talking about people who are shooting out at 300+ yards.

    Would I be afraid of buying an AirForce airgun? No. I have an old Talon SS frame I am building up and want another Edge and a Texan.




  7. Here’s a group that I shot with the 54 off a bipod today HFT style at 35 yards.I’m still trying to figure out the best position and hold for the rifle on the bipod. The smallest group of three is about 1/2 inch and the other two shots opened it up to about 7/8 of an inch. There was a cross/headwind gusting up to 11 MPH during the shot string but I tried to hold off and shoot during a relative calm . I think it shows that the rifle has a good potential for accuracy if not the shooter.Any suggestions out there from 54 shooters?

    Brent




    • Here is a comparison of my R1 with the counterweight system of my own devising and my new Diana 54. I like to shoot at the points on the target and then the middle. I shot first with the R1. The only miss is between the top point and the right point on the left target. I then followed it with the D54. All the remaining misses are the D54. I noticed that the counterweights deaden the forward piston recoil a bit on the R1 but do not stop it. The Record trigger is much better than the TO6. I also used the R10 match in the R1, which I know is a great pellet in it but not sure about the 54. The R1 weighs 11 lbs.. 12 ozs. and the 54 weighs 11 lbs. 15 ozs. The 54 have less movement in the bipod, which is something I was looking for. From this comparison, I would like to get the TO6 trigger closer to the Record in weight and I think the results would be closer.


      • Brent
        Remember the two screw in the trigger blade will adjust your first and second stage also.

        And i5guess you noticed that the trigger pulls away from your finger after the shot goes off. I found out I get better accuracy using the tip of my finger right on the bottom of the trigger blade. It kind of forms a ball as it forms the back of the trigger blade. And another note. I follow through when I pull the trigger.

        Just thought I would let you know.


Leave a Reply