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Crosman’s mysterious 451 Military .45 Auto

by B.B. Pelletier

That was the model designation, but the 451 was really a .22 pellet pistol. As famous as the Crosman 600 is, the 451 is equally unknown, except among advanced collectors. Both air pistols were .22 caliber semiautomatics with true semiauto functioning. But where the 600 remained in production a full decade (1960-1970), the 451 was only made for part of two years (’69 & ’70).

As scabby as this one looks, this Crosman 451 is still a $250 gun if it holds and shoots!

A true semiauto
As you are aware, real semiauto pellet pistols are not common. The Drulov DU-10 is one, and there are a couple of five-shot 10-meter target pistols, but pellets don’t lend themselves to being run through gun actions rapidly. This has kept their development at a minimum. The model 451 has a strange circular magazine mounted on top of the gun, and it rotates in the horizontal plane rather than vertically, which is conventional. Like the SA-6 revolver, pellets are loaded skirt-first into the six chambers on this magazine, which makes this the world’s only muzzle-loading semiautomatic air pistol.

Single-action only
Like the M1911A1 it copies so closely, the 451 must start with the hammer cocked. When it falls, it strikes open the firing valve, sending gas up the hollow tube that also acts as an axle for the cylinder. The gas pushes on the pellet in the firing chamber, sending it downrange, but a small portion of gas enters a secondary passage and pushes on a valve that impacts against the slide, shoving it backward. The slide cocks the hammer on its way back, then runs forward under spring pressure and advances the cylinder for the next shot. It all happens so fast that it’s almost impossible to detect anything beyond the noise and recoil from the shot. If the hammer fails to cock, you must recock it by hand, as this is a single-action pistol and the trigger will not cock the hammer.

The shooter feels an impulse of recoil from the weight of the moving slide, and the trigger is very light, needing only to restrain the hammer for firing. Gas pressure and springs run the rest of the operation. Actually, the sheetmetal slide is not full-sized. It runs about two-thirds of the top of the pistol, but it’s heavy enough to cock the hammer and to impart the feeling of recoil.

In its day, the 451 had no equal. It was the only pellet pistol with a realistic recoiling action. Accuracy was very good, but gas usage was the pits! Because so much gas was used for the blowback facility, the 451 got only about 18 shots per powerlet. Compare it to the 600 model, which got 30-33 shots per powerlet. That number was low, too, but compared to CO2 air pistols made today, the 451 is abysmal.

Except for the CO2 adjustment mechanism on the bottom of the magazine well and the lump in the middle of the slide, the 451 looks very convincing.

Difficult to repair
As long as it works, a 451 is reliable. When it gets out of order, it’s a bear to repair. Not all repair stations can fix one, so check before sending in your treasure. A common problem was the nylon piston that actuates the slide – it will start leaking and lose energy. When that happens, the gun will fail to cock. That repair is an easier one than tearing into the whole gun.

If you want a vintage gun like this, you’ll have to watch the auction sites and be prepared to pay for it. They do turn up at airguns shows, but the prices are high there, as well. If you just want a semiauto pistol you’re a lot better off with a Drulov or even a Crosman 600. Some of you will absolutely HAVE to own the rarest of all Crosman semiautos, now that you know they exist!

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.

25 thoughts on “Crosman’s mysterious 451 Military .45 Auto”

  1. I’ve been a fan of airguns of all sorts since I was 11, but never got to see one of those. Keep ’em coming, please! Now I know more of what to look for at the swap shop. The six months I’ve been reading this has been time well invested. Thank you.


  2. Dear B.B.,

    Do you have pictures of an old crossman 600 semi-auto pistol?
    When i was a kid back in the early 60s, i always wanted one but the cost was way out of my reach. i thought it looked sleek and there was no other auto pellet pistol back then that i knew. if the 600 is the correct one that i’m writing about, the pistol had receiver sticking back far to the rear of the gripping hand.

    i couldn’t find any picture of the pistol in the google srch!


    Schten Dohkji

  3. Mike,

    According to the Blue Book of Airguns, a nearly new 451 in the box is worth about $400, as long as it holds gas.

    If your pistol doesn’t hold, I want to caution you that there are very few people who can repair them correctly.

    If you have a small leak, just put a drop of Crosman Pellgunoil on the tip of the next powerlet before you puncture it.

  4. To Schten Dohkji, and any other interested party… Crosman 600… not one but TWO… came my way recently.
    I have made an Acrobat file so that you are able to see them.

    Just paste this link into your browser and the PDF file should download for you.


    One of these is a late model and has been completely refurbished. The other is in more ‘original’ condition and sports some Crosman plastic left hand grips and the earlier co2 tube cap, without the cylinder punch.
    Twice both pistols have round-fired… continuous bursts… for about 6 shots… on me. But I understand that this was something which did happen occasionally, even when they were new.
    Getting used to reversing the cylinder cap about 1/3rd of a turn on the older model is novel too, especially after using my favourite Sheridan Pros, which take the cylinder in facing the rear of the pistol and do not need such consideration.
    It is also true to say that these pistols are only really comfortable with Crosman ‘Pels. The older model will use Marksmans, at a pinch. But it is clear that the unique action cycles far better with Crosmans. The refurbished model simply jams immediately with anything other than Crosmans.
    Compared to my Sheridan Pro Hunters, these pistols are heavy, and much more bulky. And the Sheridans do not much ‘care’ what pellets I use in them… even to old 30 Grain Rabbit Magnums in the 22. I have not yet had a pellet snag in the breach or barrel in either 177 or 22.
    Nevertheless, these Crosman 600s are true semi-auto, something I never really expected to encounter in this field.


  5. Hello to you all. I have for sale a Crosman’s 1969 Military Issue 45 cal .22 pellet gun. I believe it is the one that B.B. said in his blog was very rare. If anyone is itereseted I can be reached at 508-885-6149. It is in great condition and fires without a problem. I’m asking 300.00 firm for it. Thanks Dennis

  6. Dennis,

    Do you still have it?

    If so, I want it! 🙂

    I can send you payment immediately.

    I will call you today!
    If your number has changed, PLEASE let me know.

    – The BBA –

  7. Dennis,

    I tried to call but the number is out of order.

    Please post up & let me know if you still have it, as I want to buy your Crosman 451 .

    Thank you,

    – The BBA –

  8. Al,

    I'm with Tom. Try those two!
    John is a great guy! Dealt with him a number of times, & I've heard nothing but great things about Rick!.

    If neither have them,
    Google Bryan and Associates.
    They hard the part I needed for mine.

    Good luck,


  9. I have in excellent condition a model 451 Crosman military 45 auto .22cal.Pellgun. I see that they are very rare. My gun is in excellent firing condition. I have had it for years and started to throw it out until I noticed only one s in Crossman this got my attention. I do not remember where the gun came from but I have had it for a long time. Just lying in my gun cabinet. I want no less then $325.00 plus shipping for it. It is as smooth as a bran new one. I see the same gun but in terrible condition bringing $250. easily.
    As I remain,

    Timothy Gilbert E.

  10. Timothy,

    Crosman has always spelled their name with one S. There is a Crossman spelling, too, but not the family who started the airgun company.

    You really won't get any attention here. This post is more than five years old.

    Also you need to know that airgun prices are depressed, like everything else right now. Prices from five years ago are now cut in half on most airguns. Yours has retained more value, though. Your pistol should be worth $250-300, but no more. That's what it would bring at an airgun show. If it came with the box it would be worth more.

    To sell it quickly, advertise here:



  11. I have this exact gun in better looking condition , have tested and still fires and holds c02, looking to sell it, if any one is interested in buying it or helping me in regards to how and where to sell it. Can email pictures and even video of the piece of history in action.

    Email me at :

    Call or text and leave message which I will return
    (856) 580-3133

    • Winterz,

      Wow — a Crosman 451! It’s worth the bid price of $250 right now, but I expect it will go for over $400 by the end of thew auction.

      Thanks. And welcome to the blog.

      Part 2 of the Forge is tomorrow and I have some surprises in store.


      • Hi, B.B. I know this is an old blog but just wanted to add for you, I just got a 451 (serial # 000029) I would say looks about 80% but works great. I really like it. Mine is getting 41 shots per C02 at 70*F before it fails to cock the hammer. It puzzles me because I read here 18 and am use to getting very accurate info from you, and so it was very unexpected. I wonder if looser tolerances due to wear have increased the shot count that much, or if someone modded it internally somehow? It makes no sense to me, any ideas?

        • DanLK,

          This wasn’t a test of a 451. It was just a review. The shot count was provided by numerous owners in other articles over the years.

          Maybe 18 is low, but 30 must be the max. Remember, shooting until it won’t blow the slide back is not a good shot count, either. We want powerful shots that are all accurate.

          I would say that you are fortunate to have such a nice airgun.


          • I agree, I did some shooting today and from 20 yards the first 38 were MOSC (minute of soda can).
            I didn’t try paper targets yet just plinking, I haven’t chonied it yet.

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