Supplemental chambers


Are these common? Can anyone shed some light on their use? Perhaps I’m on the wrong forum for this…

Thanks for whatever information can be provided.


XLIV–Welcome to our Forum. I can’t help you with your question, however you are on the right Forum with your question. Anything to do with ammunition (EXCEPT Reloading information or sale of shooting quantities of ammunition) is perfectly acceptable here. By the way, those are very nice axillary chambers. Most of them are all scratched up.


Howdy XLIV & welcome
The chambers were manufactured by Winchester for a market who wanted to shoot inexpensively, or for short range, or even perhaps for trappers killing prey without much damage to the pelt. The information on the side of the case tells what round is to be used. These were originally marketed in boxes of 6 or perhaps as singles at the local gun shop / hardware store. Some of the originals/prototypes were made of steel with just a stamp stating the caliber.
You’ll sometimes find the same caliber using different case types as yours shows the acceptable use of both the Short and Long Colt.
As to common or not, some are very hard to find & others not so, however I don’t think any are common. Think they were made for almost all the smokeless chamberings [which could accept a pistol/revolver diameter bullet] of W.R.A.Co. manufactured rifles, except for the single shot rifles.

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Thanks for the great info. I’m going to list them on ebay