Rocky Mountain arms mouse rifle


July 6, 2013, 09:48 AM
Rocky Mountain Arms made a 22 cal breech loading black powder rifle. The breech was rotated open and powder and a ball inserted, when the breech was closed a toy cap was used under the hammer to ignite the powder. ( (

If you enjoyed reading about "Rocky Mountain arms mouse rifle" here in archive, you'll LOVE our community. Come join today for the full version!
July 6, 2013, 11:45 AM
that is saweeeet!

Acorn Mush
July 7, 2013, 01:38 AM
I remember those from way back when. Shoulda bought one at the time.:banghead:

Didn't they also make a .45 caliber?

July 7, 2013, 07:56 AM
Thanks for posting this!

WHen I first started coming here I asked about these rifles and most folks seemed to think I had mental issues.

A friend and LGS owner had one in the 1970s and I thought it super cool. I seem to recall it used a common buckshot like a #4 Buck that fit the chamber with thumb pressure and then got swaged down in shooting and that it was rated for use with tiny charges of Bullseye as well as BP.

I spent some time shooting it one afternoon and while it was no tack driver it was as I like to say "a hoot to shoot" it was no worse than my old muzzle dinged much rat shot Winnie67 and that killed many a tin can.

They made a larger bore rifle I never saw or handled and I believe it was called a .44 though it used a .454 pistol ball IIRC.

Cleaning of the turret area was critical to prevent it rusting in position and that may have been part of its lack of populatiry.

Another friend referred to it as a cap gun because of the method of priming being section of paper roll cap.

It was another of those "I would like to have bought it but was a starving GI bill college student at the time" guns.


July 9, 2013, 12:59 AM
If I found one for sale, I'd pounce on it.

July 10, 2013, 12:45 PM
Me too. I remember seeing those advertized, but I don't recall actually seeing one in a shop.

December 2, 2013, 04:53 PM
I had one long ago. Always thought it a neat little plaything. Wish I could find another one.

December 3, 2013, 07:29 PM
When I was in jr. High, way, way back, I bought a Luger-looking pistol that loaded a bb from the muzzle and used a paper cap to propel it. It was either a Wam-O or a "roger". It would dent cans pretty well (steel in those days).

December 4, 2013, 09:50 AM
I posted a couple of days ago about "post-modern" black powder guns. Here's a prime example.;)

December 6, 2013, 01:15 PM
What would the load be?

That thing looks fun

Doing a search they made a .36 and a .44 as well.

Ide like to see how a paper cap set off the charge.

December 7, 2013, 09:34 AM
Don't recall the load but I used a dipper made from a cut down .22 RF. There was a small hole for the flash of the paper cap to travel through just as on the nipple of a percussion cap gun.

The few shots I fired worked just fine. The bullet I used was a round ball that was pressed in.

Never saw the "big bores".

I put it in the same category as the Daisy VL rifles, interesting and fun but not necessarily practical.

Still would like to have had one rather than borrowing one for an afternoon.


4v50 Gary
December 8, 2013, 09:43 AM
I know someone who has one. Can't buy it from him either.

December 8, 2013, 04:46 PM

Well there you go! Make a copy of your friend's gun as your "Master Piece" at school......make two while you are at it and let me know when mine is ready.


December 9, 2013, 11:54 PM
I'd love to see some more pics of the action, to figure out how it works. I want one! If I can't get one, maybe I could have something like that made?

December 10, 2013, 02:09 PM
Crazyjenny, looking at the rotating breech block and the finger knurling I would say that the block is turned by hand to the loading position shown in the picture. The bent button on the far side of the rear receiver block that holds the firing pin is likely a simple locating lock to secure the other wise freely rotating breech block in the proper indexed location.

With some slight modifications I could see this being a great design for a simple to build .22 rimfire rifle action as well. In that case a 45 degree rotation would be fine. But for this black powder version the full 90 degrees is best as it allows us to lay the rifle on its side with the breech facing up to reload without spilling.

I'm also sort of guessing that the knurled cap on the opposite side of the breech block screws off to let the shooter put a small round red cap into this holder and screw it back on to be set off by the firing pin located in the rear upper block and hit by the hammer. To me that makes more sense than a cap being located way back at the face of the hammer. And it also explains why there is a knurled cap on the rotating breech block.

The groove around the mouth of the chamber had me wondering until it hit me that it's a scraper groove. The breech block is made purely round and then an annular cutter forms this scraper groove to act as a pressure trap of sorts (google for labyrinth sealing) when fired and also produces a sharp'ish edge to aid in carving away the crusty fouling buildup when the block is rotated back open.

It's simple yet quite ingenious in the little details.

December 10, 2013, 04:14 PM
Found some discussions elsewhere and way back and it appears they used 7 grains of FFFg or FFFFg OR a small charge of Bullseye and a .24 cal round lead ball Don't have my buck shot charts but I think that is a #4 buck.

They really did use paper caps as primers. One issue seems to be that they do not make paper caps as strong as they used to.

I have found no reports of anyone actually handling a .36 or .44.....

It appears that Rocky Mountain Arms Corporation later changed their name to North American Arms NAA and made only the little Casul mini revolvers since. Perhaps some one might contact NAA and ask.


January 14, 2014, 10:18 PM
I used to have one of those. I thought it would be a great grouse or squirrel gun, and a lot less powerful than my old .32. I got the original paperwork with it and it recommended 5 grains of FFFF with a paper cap for ignition. It was truly a great idea, but one of the most worthless guns I ever had the "pleasure" of handling. It wouldn't hit a grouse at two feet and the groups looked far more like patterns than they did groups. I tried everything I could think of from crowning, bullseye, and a few things I can't remember. Finally fixed it by trading it off. Best deal I ever made.

January 14, 2014, 10:51 PM
Ide bet it was the paper caps.

How well could a paper cap ignite a charge? How consistant would they be from cap to cap?

I just like the idea of rotating the chamber that is a neat idea IMO.

January 15, 2014, 12:45 AM
I've been using a Forrester tap"o"cap for years and have never had accuracy problems with them. They are rimed with three toy paper caps. The worst problem I've had is a slight hangfire when using BP substitutes. And that isn't much.

January 19, 2014, 04:28 PM
Was scratchin' my head until kBob mentioned a "turret". Then the picture made sense. The center section rotates 90 degrees. It's shown with the action open. Very cool idea for a breach loader. Seem to recall something similar was made in the 19th century, aka "back in the day".

If you enjoyed reading about "Rocky Mountain arms mouse rifle" here in archive, you'll LOVE our community. Come join today for the full version!