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…?
RMAC
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.
The box it came in.
This is the breech (arrow).
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.
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.
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.
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.
Remember the days when you got parts lists like this?
The RMAC secret to their breathtaking accuracy.
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.
Summary
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.
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?
Siraniko
Siraniko,
That seems to be everyone’s number one concern, so I guess I will have to do it.
BB
When I was 6 I had a coon skin cap like that kid in the photo and DB!
-Y
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.
shootski
Shootski,
I seriously doubt it would fit.
I do understand the sentiment in it and I am sure it was filled with a mother’s love.
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.
shootski
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.
RidgeRunner,
How long before the dog gets to stop sleeping outside?
shootski
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
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.
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.
Hoppy,
And you never ran out of ammo! 🙂
BB
And I’m still trying to save the world . . . without much success. Orv
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.
BB,
Pretty cool stuff. The idea of squishing a ball into an elongated projectile is certainly interesting.
Chris
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.
Regards,
August
August,
Yes, that drawing is an exaggeration!
BB
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.
Oops!
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?
Siraniko
Siraniko,
It’s simpler than that.
BB
B.B.,
So a direct jump into the rifling from the steel breech cup? How big is this rifle? Maybe you could put it side by side to your Diana 27 for size comparison?
Siraniko
Siraniko
Wait a second! Is this Friday?! Where did the week go?
I like this working from home.
Speaking of work, I guess I had best get upstairs.
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?
RR,
No measuring with black powder. Just fill her up!
BB
BB,
As I did with my Pedersoli 1851 Navy Colt I bought when I was eighteen.
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.
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
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
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.
Deck
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…
https://en.wikipedia.org/wiki/Squeeze_bore
Hank
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.
BB
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.
FM
And look at all the soldiers going by looking at the tank.
Wonder what they are thinking.
“Maybe it’s not so bad to be in the infantry…”
FM
After seeing that I would know for sure at that time I would not want to be no kind of way there.
Hank,
Thanks for the link; that was a great history lesson for me. =>
Cheers,
dave
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
https://en.wikipedia.org/wiki/8.8_cm_Flak_18/36/37/41
Take note of the weight of the projectile, the velocities and the range they were getting. Incredible!
Have a great weekend!
Hank
“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.
Hank,
It is kind of strange that no one gave any thought to the sabot.
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.
Hank
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.
Siraniko
Siraniko,
It’s still Friday on this side of the globe. I forwarded your message to IT.
BB
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,
dave
Dave,
Me, too! 🙂
BB
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
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.
Bill
Bill,
I don’t think these were available for more than a few years.
BB
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.
/blog/2021/07/bug-a-salt-shred-er-part-2/
GF1,
Ah well, not everyone can be always right like I am . 😉
RR
Yep. 😉
And so much for me saying my new glasses are working good. 🙁
You must have been looking at it with a bright light and the reflection fooled you into thinking it was steel.
Yeah, that’s it.
RR
Actually that is pretty much how it went.
🙂
“I had rather be right than president.”
-Henry Clay
FM
🙂
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.
sajoe49 ,
Yes, it is small. I’ll try to show that.
Dennis Quackenbush has an NIB one in .36 cal. that I tried to buy from him.
BB
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.
GF1,
Well done Ade C. and GF1!!!!!!!!!! 🙂
Chris
Thanks Chris. 🙂
And Ade C. 🙂
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?
RidgeRunner,
I second that suggestion. Maybe a step by step series of pictures to show the loading procedure.
Siraniko
Siraniko,
Yes, I plan to show it.
BB
RidgeRunner,
I found this https://www.youtube.com/watch?v=cucN0Ny_xp4
Siraniko
RidgeRunner,
I’ll bet Dennis bought that rifle to study it for his personal edification. To the best of my knowledge he isn’t a typical collector and hated the folks who bought his pistols and rifles as speculative buys or to keep unused hanging on a wall or in a glass cabinet.
But don’t take that for the man’s word; just my rambling.
shootski
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.