Kynoch Adaptor?

I recently came across a single center fire cartridge head stamped KYNOCH ADAPTOR.

Rim diameter .440"
Body tapers from .339" to .333"
case length .645"
Overall 1.012"
Bullet approx. .315"

Any ideas what it is?

This is a common British Adaptor Cartridge for a .303 British caliber auxillary chamber (adaptor cartridge) to be used single shot in any .303 rifle. There may have been adaptors in other case types, but I am only familiar with the .303 British type for this cartridge. I am sure it was intended for practice, short-range shooting.

Thanks John,
The knowledge on this forum is really wonderful.
Jim G11

John, was that a cartridge used by the military?

There are several articles in the JOURNAL that discuss and illustrate other .303 Adapters. They can be a collecting specialty on their own.


EOD - I honestly don’t know if it was ever used by the military or not. It doesn’t strike me like a military item. Even though a loaded auxillary cartridge may feed from the magazine, another “I don’t know” because when I had them, I never tried one in any of my Enfields, the SMLE and its predecessors and antecedents are especially convenient to use with these things single-loaded, as the bolts lock in the rear, so you don’t have the push them way up into the receiver to reach the chamber. The chamber mouth is right there when you open the bolt.

There were many other types of .303 auxillary cartridges and the rounds that could be shot in them, than just the type for the “KYNOCH ADAPTOR” by the way. Ray hit it on the head - just in .303, you could probably gather a nice little collection of them. I had a beautiful chromed Winchester auxilary cartridge in that caliber, as well as a Marble’s adaptor that took a .32 Auto round, although with the bullet in .32 auto cartridges being a bit smaller in diameter than a .303 bullet, as I recall, I don’t know how well they shot even at short range. A collection of all calibers of adaptors, pistol rifle and shotgun, would be a very large collection. For example, because I collect 9 mm Para, I have retained a 12 gauge auxillary cartridge that is solid steel and has a rifled, short 9 mm Para barrel and chamber. One day I will try shooting a 9 mm in my CAS short-barrel double gun, if I ever get to a range again.
It is on my list of shooting things to do that I have not gotten to over the years.

Here is an excerpt from Kynoch’s 1901-02 price list:

John and Fede, thank you for additional info. Maybe someone else can say more about a military use?

At school we had a small bore range for use by the Army Cadets. Is it really sixty years since I was in the cadets and last shot there, sigh!!.

While not regular army, the Australian army did provide uniforms, weapons and ammunition, some .303 SMLE’s in calibre .22 LR for use at the school range., and we also went to the army ranges and used .303’s both SMLE and Bren guns. The lucky ones got to fire the 9mm Owen gun. I can still recall the order in which to strip down a Bren gun, so seems I haven’t lost all my marbles just yet :)

I think the .22’s were most likely to be the Morris tube patent. Which, if my memory is correct after all these years, were also available in 297/230 rook and other calibres.

It would seem likely that a lot of the Commonwealth countries armies used many varieties of commercially available adaptors for training purposes.

I don’t have any headstamp examples but Les Butler returned some correspondence we had some 40 years ago. I had listed the following Rook rifle calibres,

297/230 Short, 297/230 Long, 297/230 Blank, 297/250, .300 (.295), .320 Rook. I don’t recall why I listed the .300 with .295 in brackets

Would be a nice reasonably priced specialized field for a young collector.



the reason for the 300 ROOK to have .295 in brackets is that for some reason this caliber.300 rook cartridge was usually head stamped .295. I also have .255 ROOK (Jeffery) and .360 N0. 5 ROOK .

Hi Fede,
Thanks for the picture from the KYNOCH Catalog. That one is much more like the Winchester Adapter rather than the Marble’s design.

Jim, two of the most well known US cartridge adapters, which are the Winchester (Gillette patent, 1898) and the Marble (Brayton patent, 1904/1905), are basically copies of two different British patents assigned to Matthew Mullineux in 1895 and 1896.

The British military never used the Kynoch adaptor nor any of the other commercial types.

Prior to WWI a lot of investigation took place into low powered short range loads such as the Canadian Gaudet but none were ever adopted. For indoor use the army stayed with .22 calibre rifles whilst for outdoor short range use there were four marks of short range cartridge introduced for Coastguard and Royal Navy ranges.

The .22RF Pattern '14 SMLE (Not the P.'14 rifle) used steel “conveyors” shaped like a .303 inch cartridge into which the .22 cartridge fitted but that was the nearest they came to using adaptors.


Tony - thank you for confirming the lack of military use of these adaptors. I thought that was the case. I knew they used .22 rifles, some made from converted Smellies. I have a very nice Lithgow (Australia) Rifle No. 2 Mark I (? - I have not looked at it in awhile, so maybe I got that designation wrong) that despite the military trigger pull and small, open sights, shoots very well. The follower and spring are gone from the magazine (by design) and the fired cases, when extracted, fall into the empty magazine box. Keeps the range clean!:-)

The use of adaptors, auxilliary cartridges, and cartridge holders was common in the U.S. military in the years before and during WW II. I don’t think any of them are still being used, however.

Here’s a photo of a .303 Breech-Piece (Adaptor) that I have. It is one of the more common ones. I don’t have the correct Locking-Key to go with it.


As far as I’m aware these were used mostly by indoor shooters such as Miniature Rifle clubs (which were mostly shooting .22 's) but also shot the service rifle. As not exactly practical to shoot flea-O-fleas indoors, not to mention the cost, a number of adapters were used.

This variation is also found unheadstamped with a lighter bullet [total weight 137.5 g]

in Kynoch [as shown 140.6 g] a blank with a rounded petal crimp and as a dummy (with an empty primer pocket)

also headstamped " ELEY . SIMPLEX . " [130.8 g] and '" ELEY’S . SIMPLEX . " [131.3 g total weight].

two Kynoch boxes for this adaptor / adapter

Pete, very nice boxes, thanks for sharing this pictures. The .303 Simplex cartridge made by Eley for the Simplex Adaptor is very similar but in fact is a different case type with smaller head and neck diameter. It is also found unheadstamped, which means that the only way to be sure is to take measurements. The adaptor was patented in 1902 by Thomas Jones Jones.

Some Adaptor’s

Hi John Moss,

Noted your Lithgow manufactured .22 SMLE, and thought this quote from the factory may be of interest.

[quote]Rifle No.2 MkIV*

The .22 service training rifle, being a conversion of the SMLE, closely resembled the No 1. MkIII* in appearance and weight. They were single shot and had a solid barrel rather than a sleeved barrel wherein a sleeve was placed inside the .303 barrel for conversion to .22 calibre.
These rifles were still being used by cadets until 1975.



John - Very Interesting to me, although I knew the barrels were made as .22 and not sleeved .303 barrels. The model you quoted is, of course, correct. I knew I would get at least part of it wrong, but I got lazy as usual. The rifle is in the back of my safe, and I have to move a lot of stuff in and out to get to it. I had them in order based on how often I used them, with the most used in the front. It is a moot point now since I no longer shoot at all.

The first guns I ever collected were Enfields, but that was when I was a kid and you could buy them for US$ 9.95 each at our local, big surplus store in downtown San Francisco. The store still exists, but is much smaller now, and doesn’t deal in guns at all. I built a collection of over 20 from that store, paid for with my money from the four paper routes my brother and I did every day. Had to have a note from “mommy” to buy them on file at the store - those were the good old days. And yes, for the gun owner, they WERE REALLY the good old days, not just meaningless nostaglia.