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Education / Training Legends M712 full-auto CO2 BB pistol: Part 2

Legends M712 full-auto CO2 BB pistol: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

Part 1

Legends M712 Full Auto CO2 BB pistol
Legends M712 full-auto BB pistol.

This report covers:

• Velocity
• Shot count
• Summary of this test
• Full-auto test
• Pay attention to the magazine follower
• Cock the gun with the bolt
• Trigger-pull
• Evaluation so far
• I’m at the Pyramyd AIR Cup

Today, we’ll look at the velocity of the Legends M712 full-auto CO2 BB pistol. This pistol is powered by CO2, which means the gun cools down as you fire. As CO2 cools the gun, the pressure drops, so the velocity drops as well. Nothing new there, except this is a full-auto gun that has no limits to the number of BBs that can be fired in a single burst. You can empty the magazine of all 18 if you desire, so one of the things I’ll be checking is what full-auto firing does to velocity.

I loaded the magazine with 18 Umarex Precision Steel BBs , then I installed a fresh CO2 cartridge and shot a string of 10. The first shot went 364 f.p.s., and the final shot went 344 f.p.s. The average velocity for this first string was 352 f.p.s. I was waiting 10 seconds between shots to conserve gas.

Shot count
The second string average dropped to 335, with a low of 329 and a high of 344 f.p.s. A third string did almost exactly the same. Then, I waited 2 minutes and fired a shot at 332 f.p.s. That was followed by 4 fast shots that were not recorded, then a fifth shot at 309 f.p.s. So, shooting in rapid succession does cause the velocity to drop significantly.

I waited another 2-3 minutes, during which I topped off the BB magazine again. Shot 36 on the first CO2 cartridge went 332 f.p.s. Shot 40 went 330 f.p.s. At shot 43 the velocity was 322 f.p.s., so I waited another minute before shooting shot 44, which went 331 f.p.s.

At shot 46 the velocity began dropping fast, and I could tell the liquid CO2 was gone. As long as there’s some liquid, the gas pressure remains the same and is affected only by the ambient temperature. Shot 49 went 309 f.p.s.

I continued to shoot, waiting a minimum of 10 seconds between shots and watched the velocity drop to 253 f.p.s. on shot 58. By this time, the blowback was getting very weak, making it very obvious the gun was running out of gas. Shot 59 went 245 f.p.s. and was the last shot I was able to get from the first cartridge.

Summary of this test
I babied the gun during this test to get the absolute maximum number of shots from one cartridge. No one is going to shoot this pistol so conservatively — especially not when there’s a full-auto option! I don’t think the M712 is a pistol you shoot targets with anyway. It’s a gun you use to tear aluminum soda cans apart as they dance around the yard. Let’s take a look at how the gun does when it’s handled that way.

Full-auto test
A new CO2 cartridge was installed, and the initial velocity was 359 f.p.s. I shot several rounds to make sure things were working, then I topped off the BB magazine again. I waited a minute and shot one shot at 350 f.p.s. After that, I shot a short burst on full-auto. Don’t ask me how many shots it was, because it’s impossible to count when the gun shoots this fast. But the shot immediately after the burst went through the chronograph at 324 f.p.s. I shot another short burst and then another single shot, which went 314 f.p.s.

This illustrates what the full-auto function does to velocity. It drops rapidly, plus shooting the gun this way uses more CO2, because more liquid flashes to gas on each shot when the pressure drops. I say that because, after this test, I got one more burst before the pistol ran out of gas. If I had to guess I would say there were 30-35 shots in the gun when fired this way.

Pay attention to the magazine follower
When you load the BB magazine, the first thing you do is push down the spring-loaded follower until it catches. Then you can load the BBs without fighting the magazine spring. But after loading, you have to release the follower manually, or the BBs won’t feed. You’ll get 1 or 2 shots, and then the gun starts shooting blanks. Remember to release that follower! I forgot several times, which is why I’m telling you.

Legends M712 Full Auto CO2 BB pistol magazine
The magazine follower is pulled all the way down, where it locks in position on a shelf in the magazine body. Now the BBs can be loaded. But after the magazine is full, you have to press the top of the follower in so it slips off the shelf and can push the BBs up as they’re shot.

Cock the gun with the bolt
Another caution is you must cock the gun with the bolt. If you don’t, you’ll shoot blanks, or maybe you won’t shoot at all. Both things happened to me. Remember to not just pull the hammer back with your thumb like you might with a 1911 or a revolver, but do so by manually pulling the bolt all the way back.

The 2-stage trigger on the M712 is delightful. There’s a very long first stage that very positively stops at stage 2. Stage 1 takes up almost 2 lbs. of effort. Stage 2 breaks at 3 lbs., 7 oz. It’s a very nice trigger.

Evaluation so far
Umarex had me at the selector switch; so, unless this pistol does something horrible in the accuracy test, I’m prepared to like it a lot. You have to think of this one differently, because it really isn’t a conventional air pistol. Even as a firearm, there’s nothing conventional about a pistol that shoots full-auto at the flip of a switch.

I’m at the Pyramyd AIR Cup
I’m flying out today to Ohio to attend the Pyramyd AIR Cup. It’s a 3-day event of field target and silhouette matches, fun shoots and more. I’ll have limited time to attend to the blog and hope our regular blog readers who aren’t attending this event will help answer reader questions.

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.

43 thoughts on “Legends M712 full-auto CO2 BB pistol: Part 2”

  1. I wish they would combine this gun with the steel storm.

    What I mean by that is the steel storm has if I remember right around a 350 count bb resivoir and a spring loaded bolt you pull back and tilt the gun to load 30 bb’s. It has single shot or 6 round burst switch.

    What I would like to see is the storm to have a full auto selector like the m712. Or the m712 have the resivoir and 30 shot capability. That would be two nice guns if they combined the features.

    I tell you what my little steel storm is a heck of a fun gun shredding cans even with the 6 round bursts. And the m712 has got to be a blast in full auto until the clip runs dry.

    The steel storm is the only bb gun that has managed to stick around. Ain’t nothing like can shredding you know. And I’m sure the m712 has the fun factor thing happening also.

    • I’m still thinking about an affordable Tommygun replica the SMG is $600 and you gotta load the belt, Feltman’s are approaching $1000 but a second handle makes it a lot easier to control ’em in full auto!


    • I never warmed up to the Steel Storm because there is no way to attach a stock, however when they came out with the Steel Force, they caught my attention.

      Yes, it would be real nice to be able to rip out a 30 round burst. It probably uses so much CO2 that you would have to develop bulk fill magazines.

      I think I just might have to pick up a M712 and like Reb, hope they bring out the Thompson.

      • RR
        My steel storm ain’t to bad on Co2 I think the double cartridges help. And I have rapid fired the 30 round magazine empty many times. Remember that’s only 5 pulls on the trigger when you are in the 6 round burst mode. it will shred a can nicely. And I haven’t noticed that it slows the gun up. I haven’t chronyed it either and don’t care to if its knocking the can around.

        And I got a good NC Star green laser on it. You can seriously see the dot on a tree 150 yards away in the day time. Of course I don’t shoot it out to 150yards. 🙂 But it is fun to put the gun down at your hip and point the laser at the can and start unloading. Plus if its misty out and the smoke or whatever it is that comes out of the gun will show a nice laser trail.

        All I can say is fun stuff. And I’m with you and Reb on the Tommy gun. In full auto of course. 🙂

  2. Even with the drawbacks of this thing sucking down BBs and CO2 cartridges like it does, I had to put this in my Wish List. Like BB said, this is for when the homestead is being attacked by a pack of feral soda cans.

    I guess I had better put spare magazines, BBs and CO2 cartridges on the Wish List also.

  3. Well, it looks like they have finally gone and done it. They have turned the Marauder into a Mattelomatic.

    I have to admit that I do like the picatinny rail. I wonder if this will drop into the Marauder stock?

    • RR
      Yep they are on the AR/MSR bandwagon like all the other gun makers out there. Since the Newtown shooting and the ammo shortages the gun makers saw a boom in the sales of the AR/MSR platform guns and crosman appears to want in on the action. The problem that I see is that with the scope and bipod it weighs over 10 pounds and my homemade AR with all the same added components is only a little over 6 1/2 pounds so while it is appealing to the people that want a AR lookalike in a pellet gun it is way to heavy for it to be anything more than a bench rested shooter.

      I would by a MAR 177 pcp conversion before the Armada as it will perform just as good and will fit right onto my AR lower so that I can make my firearm into a pellet gun and only spend 600 bucks instead of 1000 bucks and it would be lighter as well.


    • RR
      Im kind of betting it will. I haven’t found any pictures good enough to tell yet. And that’s pretty similar to what Dave at RAI is doing with the stocks he is making for the first gen Mrods. He uses his AR adapter and has a frame assembly that goes on the gun over the trigger so it has a pistol type grip. But the stock goes about 6” forward of the trigger if I remember right.

      I had pictures on my old phone that got accidentally deleted. But I had a Disco with a 1377 pistol trigger assembly on it and a1399 stock. It was a nice lite gun. Very easy to carry around.

      Then I had that first gen .25 cal. Mrod and put the 1377 pistol trigger grip assembly on it with one of Dave’s adapters with a AR stock and it was the gun that had that Double tube kit on it that Lloyd made for me that basically started the double tubes for the Mrods from him. It definitely looked like one of those big scary black guns if you know what I mean. If I would of had that gun out in public I’m sure There would of been some kind of excitement.

      And I guess some people like all those picatinny rails to attach all that tactical stuff but that just ain’t for me. The Hatsan QE that I got has that picatinny rail on the bottom about 3” long and that’s more than enough for me. A bi-pod mounted there would probably be as far as I would go.

  4. Regarding the magazine follower, I had a problem with a gas pistol of mine that had a similar arrangement. When the follower was locked in the bottom position, if you allowed it to escape it would slam against the top of the magazine and could be so deformed that it would no longer runs smoothly through its channel. To avoid this, I simply put one BB while holding the follower manually, and only then I would push it to the bottom position. Then, only when all BBs were in the magazine, I would let the follower go.
    I don’t know if this is the case with this pistol, but on mine, the follower would escape its lock very easily.

    • You can place a small straight blade screwdriver into the slot and push the follower down while you load as many bb’s as possible and then finish up using your thumbnail.

      I have a UZI converted to auto selective fire and also the Steel Force with single and 6 shot burst modes. I like both of them a lot for different reasons.

      The Steel Force has a 2-cartridge magazine and the bb’s are loaded separately by a difficult process of tilting the gun in various inclinations to persuade the bb’s to roll into the built-in magazine. This process is cumbersome and risks muzzle sweeps of the area around the shooter. I intend to work on the loading process to improve the safety and speed of the process. The double cartridge magazine and the slow reload process reduces the CO2 cartridge cooling problem as well as the 6-shot burst mode rather than full auto mode of the UZI.

      The UZI on the other hand, has only single or full auto modes. So cartridge cooling is a factor except for the limit of the 25 round limit of the magazine. Also, the mass of the magazine probably delays the cartridge cooling effect somewhat. Also, I have several magazines which carry the single CO2 cartridge to interchange to let each cartridge warm up before reuse. The recoil of the UZI is pretty heavy if not held tight to the shoulder and muzzle rise seems pretty realistic (no, I have never fired a real UZI!).

  5. Sorry for being off for too long. End of the year, lots of job – you know it.

    So I started getting things together for Mk.2 opposing pistons rifle. With all previous flops corrected it is going to be something interesting and, I hope, more useful and closer to airgun than proof-of-concept Mk.0. S.A. guys seem to be consumed by their own work and fell off, so I believe I’m going to be alone with that. Well, spring will show who had a bad appetite last summer 🙂


  6. If you look at the reviews on this thing, there is an issue with the outer(fake) barrel staying tight. Tightening the grub screw just bores through the cast metal. I had to make tiny shims out of a soda can and epoxy them in place to fix the problem. I also shimmed the far end of the actual barrel to keep it in place. Now this thing is amazingly accurate in semi auto, and full auto is just ear-to-ear-smile-ridiculous. I went through 10 co2 cartridges last night in my garage…

  7. The magazine construction looks like it may cause another failure I have seen with my airsoft pistol. Once you are aware of the issue, you can avoid it, but if you don’t understand the scenario, it will drive you crazy.

    The pistol’s bolt includes a bar that rides in the groove at the top of the magazine. When the bolt cycles, the bar moves to the rear allowing a BB to rise in front of the bar. When the bolt closes the bar pushes a BB out the front of the magazine into the chamber. All pretty straight forward. Except…

    If you don’t count the BBs when you fill the magazine, and go beyond “max capacity” AND then insert the magazine with the bolt closed, the bar pushes down on the top BB. That pushes the whole stack of BBs down and the magazine follower catches at the bottom. You end up getting one shot, then the magazine fails to feed any more BBs.

    The solution is of course to try to not push the capacity of the magazine. (I find that hard.) An alternative is to always load your magazine into the pistol when the bolt is open.


  8. To all of you who are worried about the dropping velocity on full-auto, I alone have the answer to this seemingly insurmountable problem of chemistry! Just shoot at five yards like me, and you won’t notice any dropping velocity. You won’t lose any realism either. The cardboard maze in which I shoot with boxes against the wall for soundproofing and a big box at my muzzle to dampen sound looks like Stalingrad.

    I do wonder how long the thrill of full auto lasts. I hosed down some brush with biodegradable airsoft bb’s from my M4 and made them thrash. It was fun. But it got a little repetitive and kind of expensive with ammo.

    I must present the finale of my novel. We had SEALs fighting reptile humans in the sewers of New York. Just when things looked impossible, a survivor of the SEAL team opened up on the flank of the horde of reptile men with his M16, grenade launcher and magnesium flares. Everything collapsed into a chaotic montage of images. A homeless man ran up to a pile of skulls, a site of human sacrifice and said, “Call me a drug-addled bum will you?” before detonating a claymore mine that he had squirreled away. The team broke for the exits but the reptile men began a hot pursuit. Seeing that they would never be able to escape the “terrible loping speed” of the pursuers, a scientist waited until they the reptile men were bottlenecked in a tunnel and just about to catch up. Then, she whipped squeeze bottles out of her backpack, faced the assailants and said, “I’ve got 7-decholoresterase here. Billions of units. Enough to kill you all ten times over.” The reptile men somehow understood this to mean that she had a Vitamin D solution that was deadly to them with their fear of sunlight. She sprayed them back into their holes, then the C4 charges went off providentially, sealing away the reptile men forever. The last bit with the Vitamin D was a little over the top. So that was the ultimate weapon we were looking for. But it was an all-around good time.


  9. If I could just upload them directly, sure. I haven’t set up a photobucket account, and lack the time/patience to do so. However, just carefully cut a tiny rectangular patch of aluminun can, and apply a thin film of epoxy on one side. Then wrap it around the frame where the outer barrel slides over (where the grub screw will tighten against). I used enough so that it wrapped all the way around only once with no overlap. Then put a small o-ring around the muzzle end of the barrel (right by the existing plastic sleeve). Then put it together, lightly snugging the grub screw) and let it set up for a full 24 hours. It should be bomb-proof after that. Like all of the others that I read about, my outer barrel was droopy (causing it to shoot high), so I let mine set up upside down with a weight sitting on the barrel (a pack of Daisy BBs).

    • Diaboloslinger,

      I don’t know why I didn’t think of this earlier because I use the Pyramyd AIR Customer Pictures feature all the time. On the Pyramyd AIR products page for the M712, there is a link called “Share your own images”. You could post any of your pictures of the M712 modifications there, then after Pyramyd AIR approves and posts them, post a reply in the blog with a link to the pictures on Pyramyd AIR.

  10. Tom,

    “Shooting in rapid succession does cause the velocity to drop significantly.” Yes, but shooting in rapid succession does cause the shooter’s smile to widen significantly! :^D

    This M712 is soooooo much fun. (It would be tragic if a well-done MAC-10 were not made a part of the Legends product line.)


  11. One recommendation from a guy who still loves his old drozd, thinkgeek has an ice tray that makes ice shot glasses. I don’t use those for drinking, I set them up and full-auto BB them to fragments. All the fun of shattering glass without ever having to clean up afterwards provided it’s above freezing, which it must be if you’re using a CO2 gun anyway.

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