Home Blog  
Ammo RMAC .22 caliber breechloading black powder rifle: Part 1

RMAC .22 caliber breechloading black powder rifle: Part 1

RMAC 22 rifle
The .22-caliber Rocky Mountain Arms Corporation breech-loading black powder rifle.

This report covers:

  • What if…?
  • Format change!
  • RMAC
  • How it works
  • Who was RMAC?
  • Smokeless powder?
  • A find
  • Summary

What the heck is a black powder rifle report doing in an airgun blog? Well, if you’ve been a reader for any length of time you know that it all ties in. Today we are looking at a remarkable rifle that exists because someone asked, “What if…?”

What if…?

Black powder ignites very easily. What if we made a black powder rifle that used toy caps to ignite the charge?

What if the rifle didn’t use bullets, but common buckshot that you can buy in 25-pound bags for very little?

What if we made this small, for kids to use?

If we did all that and it worked, what if we made it larger, like .36 and .44 caliber?

Well, “they” did. And it did work — or at least I think that it did. All that I know about black powder and the explosive power of toy caps tells me that it should work. I guess we’ll find out together.

And now “we” (not “they” but “we”) have a chance to try it! And by the way — they are everyone who is not us.

And, by the way, when this rifle was sold in the 1970s, a 25 pound bag of buckshot was probably $12-15. And people back then griped because .22 long rifle shells sold for $10 per 500.

Format change!

Spoiler alert! I’m about to change the format of my report this one time. Because what I am now talking about is something I have talked about before — both recently and in the distant past.

Reloading rimfire cartridges: Part 1
Reloading rimfire cartridges: Part 2
Reloading rimfire cartridges: Part 3
Reloading rimfire cartridges: Part 4
Reloading rimfire cartridges: Part 5
Reloading rimfire cartridges: Part 6
Reloading rimfire cartridges: Part 7
Reloading rimfire cartridges: Part 8

Are you getting it? No? How about this?

What IS an airgun?
They overstepped the line!
Zimmerstutzen air rifles

Is it coming through yet? For centuries men have been using the power of explosive percussion systems to propel small projectiles without the use of gunpowder. And other men (and boys) have wondered whether, if percussion caps will do all that, what happens when you add gun powder? What if…?


And in the 1970s, “they” — the Rocky Mountain Arms Corporation, better known as RMAC, put it together and made three breech loading black powder arms, a .22, a .36 and a .44. BB used to own an RMAC .22, but he never fired it. He sold that one years ago to someone just like him who was captivated, not so much by the gun, but by the idea that spawned it.

RMAC box
The box it came in.

RMAC breech
This is the breech (arrow).

RMAC breech open
And here the breech is open.

Who was RMAC?

RMAC are the guys who brought you the .454 Casull revolver. They are also the guys with the .22 rimfire revolvers that are so small they fit in a belt buckle. They were in Salt Lake City, Utah. They evolved into North American Arms Corp. of Provo, Utah.

Stock Up on Shooting Gear

How it works

The way this thing works is, a toy cap is placed inside a steel breech cup that is then placed over an opening the leads to the chamber. A pinch of black powder has been put in the chamber and a number 4 shotgun lead shot — a so-called buckshot size, because it large enough to kill a deer — is pushed into the chamber, in front of the black powder and the rifle is loaded. When the cap explodes, the force is sufficient to set off the black powder in the chamber which then explodes and drives the number 4 shot out the rifled barrel at high velocity. At least that’s the theory.

RMAC shot sizes
If you have been a reader for several years, you have encountered this chart several times in several different ways.

Smokeless powder?

The RMAC directions say to use 5 or 6 grains of 4F or 5F black powder. I never heard of 5F, but it must be extremely fine, because 4F is used to prime the pans of flintlocks. 

However, if you wanted to you could use 1-3/4 to 2 grains of Bullseye, which is a smokeless powder. Usually you are warned to never use smokeless powder in a black powder rifle, but RMAC says they proofed the gun with a double charge of it.

Better caps

Toy caps exist in all shapes, sizes and power levels. We discovered that when we started reloading rimfire cartridges, didn’t we? And the bigger/hotter bang produces the more reliable ignition for the black powder. So before long, RMAC was specifying and even selling toy caps for their guns that were “right.”

And RMAC told you to cut each cap out round with a paper punch. “A whaaaat?” asks the millennial. A paper punch. You’ll find it in the center desk drawer, next to the whiteout.

RMAC caps
These caps were sold by RMAC and were “right” for their guns. You’re shootin’ Big Shot caps!

A find

I was recently offered the opportunity to purchase an RMAC .22  like new in the box. I bought it from Dennis Quackenbush who was the original owner. It came with all the paperwork and stuff 

I will get into all the particulars as we go, but for now let me show you what RMAC gave you and a page from a 1973 Shotgun News where this rifle was advertised.

RMAC parts
Remember the days when you got parts lists like this?

RMAC Swaged ball
The RMAC secret to their breathtaking accuracy.

RMAC price
And there is the price in 1973.

The difference between this rifle and the one I owned before is — I’m a-gonna shoot this one! We will find out together just how accurate and fun it is! I note that the boy on the box sleeve is shooting his without safety glasses, but I think I will wear mine — black powder being explosive and all that.


We have a chance to look at something that couch commandos reinvent every decade or so. But this time we have the real deal. This should be fun.

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.

69 thoughts on “RMAC .22 caliber breechloading black powder rifle: Part 1”

  1. B.B.,

    I know you will be addressing this in future installments, but how long before the ball is swaged down into a cylinder? What is the exit diameter? Probably you can shoot a few into a container to recover the shot. Will they be consistent?


    • Hey Yogi,

      Had a coonskin cap too! Had Family that owned a big dairy farm near Birdsboro and the Boone Homestead. Watched all the Danial Boone movies and TV show to include Fess Parker (not Boone for once) in Old Yeller! Yea I cried on that one…
      My mother sewed me a Buckskin Suit for Christmas with FRINGE, she had learned how to craft Lehderrhosen when she was a young women in Yugoslavia.
      Wish I still had that suit.


        • RidgeRunner,

          Yea, it would need to be lengthen on the leg bottoms and sleeve ends cause I got much taller. The waist could stay the same and the chest and back would need to be let out…i guess to much chest beating has made it swell up over the years…LOL!
          Actually i always wanted it around for my grandsons. It got “lost” during a play my son was in while in elementary school.
          So for my grandsons i got them Dog Tags Flightsuits and Helmets at the Navy Exchange in Pensacola.


    • Yogi,

      Up until a few minutes ago, I wanted a skunk skin hat. My dog just found one for me, but the skunk was still using it.

      Maybe I want one even more now.

  2. BB
    Kind of a cool idea to swage the lead ball to a bullet shape with the barrel.

    To me it seems that powder charge is making some pretty heavy pressure to swage that ball.

    Looking forward to some velocity and accuracy tests. I’m wondering how consistent the velocity is going to be.

    • Gunfun1,

      I’m also wondering how much energy is lost from swaging the .24 ball to, I suppose, a .22 cylinder? How abrupt or gentle is the swaging within the barrel? Velocity consistency will probably be affected by the regularity of the buckshot being loaded.


      • Siraniko
        Yes that too. And what I was basically meaning is that the black powder charge has to be making alot of pressure to swage that bullet and still send it out the barrel with some decent velocity.

        I would like to see a picture of the lead shot before and after it was fired.

        If it is accurate it makes you wonder why more gun makers didn’t use the barrel to swage bullets or pellets. But thinking more about it they do. But at the opposite end of the barrel. Its called a choke.

        • GF1,

          Black powder “explodes”, but I am sure you know that. There is a lot of force that has to go somewhere. Look at the breech mechanism for this rifle. There is a lot of steel there. The swage section of the barrel is encased in a big chunk of steel.

          That lead ball, being relatively soft, is going to be swaged and is going out the end of that barrel.

          • RR
            Yep and that’s why I’m interested in how the velocity and spread is when BB test the velocity.

            If these guns were still being made today (the small .22 caliber) I would love to have one.

  3. BB: Have you been searching my desk drawers? That’s EXACTLY where my single hole punch and the White Out are. And oh . . . I too recieved and wore my coonskin cap which I was given for my 9th birthday in 1956. Oh my, but the forts we built and protected with our cap guns from ramparts carefully carved out. Our precious days of yore. I’m remembering the smell of the caps exploding as they went “bang, bang”. . . and the bad guys fell dead as we protected the women and children. Yes, we really did believe in these things back in those times. Thanks for the memories, Tom. I’ll close my eyes in peace now, Orv.

  4. Mentioning the possibility of using smokeless powder with the caps…
    I wonder how long it will take before angry black powder guys start making unpleasant comments.
    I am certainly going to enjoy this series, and learn.

  5. BB,

    That picture is a slight overestimation of the process of swaging.

    I would not expect that much of the swaging action. A quick estimation is that you will get a band of appr. 0,024 inch around the ball. Basically that will work as the flange of a pellet in sealing the barrel. It will stabilize the roundball in flight only because it is rotating.



  6. Gary Barnes used to have a series of air rifles that used OO buck shot. He had found that the size is not very precise as it comes from the manufacturer. What he did was provide a swaging die that would swage the OO buck into a .32 cylinder to fit the air rifle bore.

    Using the power to swage the ball from roughly .24 down to what, .22 maybe? It should not use too much energy. Do keep in mind that illustration is an exaggeration. That is a substantial breech. Also, the swaging section is probably the length of that front block so it is likely quite gradual. Leading would be a concern of mine.

    Quite frankly, I would really like to have a long barreled air rifle that I could swage buck shot down for it.


    How it works
    The way this thing works is, a toy cap is placed inside a steel breech cup that is then placed over an opening the (that) leads to the chamber.

    • RidgeRunner,

      Maybe it works like the Paradox barrel? The simplest method would be for the manufacturer to buy .22 caliber rifled barrels then open up the breech end to accommodate the .24 caliber No. 4 buckshot. How deep is the smoothbore in relation to the barrel will probably be revealed by Tom in the next installment. To have a consistent powder charge, a smart lad would probably have premeasured charges of blackpowder, maybe in empty .22 rimfire casings?


  7. Another thought. I am certain with practice the loading evolution could become rapid, but at the start it must seem right fiddly. Like, how do you measure your loads in the field?

  8. BB-

    I recall seeing 5f powder, but don’t recall any manufacturer details. We used to ‘fine up’ our 4f priming powder for quickest possible ignition. A wooden mortar and pestle or a flat board and wooden roller were used. You didn’t want it too fine (absolute dust), just finer than 4f.

    For reference, a 12 gauge 3” shell holds 41 #4 pellets and a 2-3/4” shell holds 27.

  9. BB

    This one will surly bring out the the best we got by late Sunday night.
    That boy with no safety glasses lived long ago when there were no lawyers or else they had bigger fish to fry like smokin backy.
    Is the swaging described here much different than a soft lead Minnie ball being shoved down a rifled barrel by exploding black powder.
    The steel in your rifle must be high quality stuff to safely handle a double proof load of Bullseye.
    Thanks for making my weekend.


    • Deck,

      The swaging process shown here is different than what happens to a Mine ball. The Mine expands into the bore with the pressure of combustion. It isn’t squeezed down, it is expanded.


      • BB

        Thanks for that. I somehow believed the soft lead was initially compressed into a more dense mass which gradually became less dense as it travelled down the barrel. I thought the conical shaped Minie exited the muzzle longer in length than when loaded with a patch around it.


  10. Interesting rifle BB!

    You had one and never shot it??? Can’t understand that LOL! I have my favorites but all my guns get regular trigger time.

    The “squeeze bore” idea has been around for a long time. Even read about one in .22 rimfire. Seems that the main advantage is to increase velocity but barrel life is a problem.

    I saw one of the sPzB 41 guns in the Ottawa War museum years ago, pretty cool design. https://en.m.wikipedia.org/wiki/2.8_cm_sPzB_41

    Here is a good link…


    • Hank,

      I’ll make up for it with this one. I even have the “right” caps! 😉

      And that squeeze bore anti-tank gun was a real treat! Thanks for the link.


    • That is a compact tank-killer; the problem is the ammunition was expensive and required scarce tungsten carbide for the projectile core, though Germany could rely on tungsten imports from nominally neutral Spain until 1943 or so.

      If you really wanted to knock out the Russian heavies, though, it was best to hit them with the reliable, relatively high velocity “88” ammunition, as attested to by this thoroughly wrecked KV1 52-tonner destroyed near Lemberg/Lwov (Russian-occupied Eastern Poland) in the early stages of Operation Barbarossa.

      • You are welcome Dave!

        The WW2 air war – specifically fighter planes – are of interest to me (I fly “virtual” Spitfires and Messerschmitts 🙂 ). Related to flying the planes is the danger of anti-aircraft guns. As cool as the squeeze-bore gun is the most impressive (IMHO) and versatile gun in WW2 was the German 88 mm Flak.

        …a bit more reading if you’re interested

        Take note of the weight of the projectile, the velocities and the range they were getting. Incredible!

        Have a great weekend!


        • “The new gun fired a 9.4-kilogram (20 lb) shell at a muzzle velocity of 1,000 m/s (3,280 ft/s), giving it an effective ceiling of 11,300 meters (37,100 ft) and a maximum of 14,700 meters (48,200 ft)”
          Hank, holy cheeseballs! You aren’t kidding; that’s pretty incredible that they could launch a 20-pound shell that fast and that high (back then)! Thanks for the link, and have a great weekend. =>

    • Hank,

      Pretty interesting concept. Leave it to the Germans to design something that is very effective and efficient, but is complicated and difficult to mass produce. They are really good at that.

      • Yeah, I guess they never thought of that. Don’t recall any examples of sabots being used back then.

        They are common enough now – I used to shoot .50 caliber sabotted slugs through my 12 ga Hastings (rifled and cantilevered for a scope) barrel with pretty good accuracy.

        Some of the local areas (with lots of deer) are designated bows and shotguns only and the Hastings was easily good out to 100 yards.


  11. B.B.,

    I know it’s the weekend but the RSS feed seems to have been shut down. Especially on the mobile versions. I keep getting a message informing me it is forbidden.


  12. B.B., what a find! And I am SO glad that you are actually going to shoot this thing and report on it for us; yeah, it’s “not quite an airgun”…but the cool factor is off the charts! I love the photo on the box. =>
    Really looking forward to this set,

  13. B.B.,

    I am so thankful that you still have that unquenched thirst to find out for yourself if something that promises to shoot a projectile is worthy. I honestly love and respect you for still having this burning desire. I don’t care if this thing is accurate but can’t wait for your testing. Should be a fun ride since I never heard of these things and thought I knew everything about my era. Humbling

  14. BB –
    Congratulations on finding one to test. I must admit that I wanted one of these, but have never seen one in person.
    How long were these offered for sale when new?
    I truly hope that this leaves us (especially you) pleasantly surprised in your upcoming test.


  15. All

    Gunfun1 was wrong.

    Started looking at the Bug A Salt Shred er tonight.

    I posted a comment and a picture on the Shred er report tonight.

    Heres a link incase a person doesn’t want to search back.

  16. I have one of these in new unfired condition in the original packing. I had bought it to see how they operated because I wanted the .36 long rifle and had one on order but they went out of business before I got one. I’m not sure if they ever produced a sell-able quantity in .36 or .45 since I have never touched one. Anyways a couple of comments I wanted to make: tell everyone how small this rifle is. I think it would be too small for most 10 year olds now. The other thing is that this is just another version of the Wil‎kinson Turret rifle. Everything old is new again.

  17. A quick update.
    I messed with the Shred er salt bug gun today.

    First its quiet. Second it is on the money with the sights. And it does pattern nice.

    But here is the cool thing. I tried different things to reload the clips. Ade C’s idea worked the best. And its pretty simple to do and actually works better than the factory loaded clips.

    Oh and to mention it works on eliminating the big and small pest ants.

    Check out the part 2 Shred er report. I gave a little more details there on reloading the clips.

    So far very happy with the Shred er and reloading the clips.

  18. BB,

    Maybe I missed it, but most everybody seems to be concentrating on the swaging. What I am curious about it how the cap is fired and how it ignites the powder. Please do attempt to illustrate such for us.

    Dennis was probably nice enough not to laugh in your face when you tried to buy the .36. NIB? I could not stand it. I am not that kind of collector. I would have to shoot it. I would also scour the world for caps and figure out a way to either make them or have them made.

    Well, maybe. I guess it would depend on how cheap I was able to get it for. If I had picked it up for say $50 and knew I could sell it for $5000 if I left it NIB, I might fondle it a little bit and move it on. It could not stay at RidgeRunner’s Home For Wayward Airguns and not get shot.

    Did you happen to take any pictures of the .36?

  19. BB,

    OK, I think I have it figured out. the knurled piece has a hole through it and internal threads. It holds the cap onto the “nipple”. The hammer strikes the end of a relatively large diameter firing pin which is spring loaded. It comes forward and smashes the cap against the “nipple”. “Houston, we have ignition.”

    I like this action. I would not mind having this in .36. Tell Dennis that rifle of his really needs to go on vacation here at RRHFWA.

Leave a Comment

Buy With Confidence

  • Free Shipping

    Get FREE shipping on qualifying orders! Any order $150+ with a shipping address in the contiguous US will receive the option for free ground shipping on items sold & shipped by Pyramyd AIR during checkout. Certain restrictions apply.

    Free shipping may not be combined with a coupon unless stated otherwise.

    View Shipping Info

  • Shipping Time Frame

    We work hard to get all orders placed by 12 pm EST out the door within 24 hours on weekdays because we know how excited you are to receive your order. Weekends and holiday shipping times will vary.

    During busy holidays, we step our efforts to ship all orders as fast as possible, but you may experience an additional 1-2 day delay before your order ships. This may also happen if you change your order during processing.

    View Shipping Times

  • Shipping Restrictions

    It's important to know that due to state and local laws, there are certain restrictions for various products. It's up to you to research and comply with the laws in your state, county, and city. If you live in a state or city where air guns are treated as firearms you may be able to take advantage of our FFL special program.

    U.S. federal law requires that all airsoft guns are sold with a 1/4-inch blaze orange muzzle or an orange flash hider to avoid the guns being mistaken for firearms.

    View Shipping Restrictions

  • Expert Service and Repair

    Get the most out of your equipment when you work with the expert technicians at Pyramyd AIR. With over 25 years of combined experience, we offer a range of comprehensive in-house services tailored to kickstart your next adventure.

    If you're picking up a new air gun, our team can test and tune the equipment before it leaves the warehouse. We can even set up an optic or other equipment so you can get out shooting without the hassle. For bowhunters, our certified master bow technicians provide services such as assembly, optics zeroing, and full equipment setup, which can maximize the potential of your purchase.

    By leveraging our expertise and precision, we ensure that your equipment is finely tuned to meet your specific needs and get you ready for your outdoor pursuits. So look out for our services when shopping for something new, and let our experts help you get the most from your outdoor adventures.

    View Service Info

  • Warranty Info

    Shop and purchase with confidence knowing that all of our air guns (except airsoft) are protected by a minimum 1-year manufacturer's warranty from the date of purchase unless otherwise noted on the product page.

    A warranty is provided by each manufacturer to ensure that your product is free of defect in both materials and workmanship.

    View Warranty Details

  • Exchanges / Refunds

    Didn't get what you wanted or have a problem? We understand that sometimes things aren't right and our team is serious about resolving these issues quickly. We can often help you fix small to medium issues over the phone or email.

    If you need to return an item please read our return policy.

    Learn About Returns

Get FREE shipping on qualifying orders! Any order $150+ with a shipping address in the contiguous US will receive the option for free ground shipping on items sold & shipped by Pyramyd AIR during checkout. Certain restrictions apply.

Free shipping may not be combined with a coupon unless stated otherwise.

View Shipping Info

Text JOIN to 91256 and get $10 OFF Your Next $50+ Order!

* By providing your number above, you agree to receive recurring autodialed marketing text msgs (e.g. cart reminders) to the mobile number used at opt-in from Pyramyd AIR on 91256. Reply with birthday MM/DD/YYYY to verify legal age of 18+ in order to receive texts. Consent is not a condition of purchase. Msg frequency may vary. Msg & data rates may apply. Reply HELP for help and STOP to cancel. See Terms and Conditions & Privacy Policy.