A couple of years ago a number of very interesting conversions of Lee Enfield Rifles began to show up on the collector’s market in the UK. There was no details of where they had come from, or even a definitive answer as to what they were for and several years on the mystery remains. These rifles featured a shortened No4 rifle action, with a No 5 butt stock, wire wrapping to the handguard and a large cylindrical discharger at the muzzle:
The first theory as to the rifle’s use is that it was for firing tear gas canisters as an anti-riot weapon and comes from India. The second theory, and the one I feel more likely is that it is a line thrower used by the Irish Navy. A line thrower used a blank cartridge to fire a line between two ships and whilst I cannot find any pictures of this weapon being used in that fashion, I have found examples of the M14 being used by the US Navy for the same role and the similarities are clear:
To return to our rifle, however, the individual components are very interesting. The buttstock comes from a No 5 rifle and so has the rubber buttpad to absorb recoil, a useful feature on such as short rifle:
Moving forward we can see that the receiver is from a wartime No 4 rifle, complete with the simplified economy sights (completely redundant now as the discharger blocks any sight picture you might get through them!):
The rifle’s original designation of a No4 Mk I remains on the side of the receiver, and the serial number and date on the socket are also unchanged:
The magazine has been modified internally to only accept short blank cartridges, presumably for safety as a live round accidentally fired form this rifle would have resulted in it blowing up and killing the user! To further distinguish the magazine, it was painted red, although little of this paint remains on my example:
The force of firing from a cup discharger can quickly result in the stock of a rifle shattering, so to reinforce this rifle, the cut down forestock has been wrapped in copper wire that has been soldered together for strength:
Note also the bolt passing transversely through the stock to add further reinforcement.
The cup discharger itself is a large metal cylinder which in this case is too wide for a traditional No36 grenade, again adding credence to the idea that this was for line throwing. The discharger cup would once have been removable, but is now welded to the rifle as part of the deactivation process:
The large vent at the bottom can be opened or closed to regulate the gas flow and thus the range.
This rifle is fascinating and it is very frustrating that we still do not have a definitive answer as to its use or even country of origin. Hopefully more information will come out in the future and I will be able to revisit this post with some more concrete facts.
Tales from the Supply Depot 
I seem to recall seeing the Martini-Henry used as a line thrower so why not this as an upgrade ?
The magazine, however seems to be intended more for rapid fire which, along with the adjustable range seems to lend credence to the canister launching idea, since they need to be adjusted for range where a line thrower only needs to reach the intended target and if it goes a little bit past it, so much the better as that gives more of a chance to catch the line before it falls back due to the motion of a vessel.
I could look it up I suppose but it’s more fun taking a WAG 🙂
It’s an old conversion though, a less elegant or refined weapon 😉
Just as an aside, our Navy and Coast Guard have upgraded to a C7 based line thrower.
Thinking more on the adjustable gas setting, it might be useful for both applications.
It’s possible to shorten the range by launching whatever you need to go somewhere at a higher angle but that increases both the altitude the shot reaches and the ‘hang time’ beforfe it lands.
For crowd control, which I’m well versed in, this isn’t that much of a problem except in areas with very high buildings or in windy conditions that might knock the canister off course into your own lines, which is why you generally aim to ‘bounce’ the shot along the ground where you want it unless you need to hit a point target or breach a barricade.
For a ship launching a line, which I am not very experienced in, I can see the need for a lessened altitude to avoid entangling the line in the superstructure, masts, radars, etc; and with both vessels making way, a long ‘hang time’ might mean a complete miss since the vessels are moving.
I’d suggest that the gas adjustment would be more useful for a line thrower, the other projectors we used for riot control didn’t have any adjustments and if someone got hit, oh well. they shouldn’t have been ‘disturbing the peace tumultuously’ to begin with.
I still think it would work for both purposes but I think it’s a line throwing device for several reasons.
It is, however, quite similar to a ‘Burns Cup’ dispenser for modified Mills bombs and might well have found repurposing on board HMS’s being cut down to improve handling on deck and because the range is much shorter and the initial line to be thrown fairly light.
There is mention of a rod with an eye at the end to attach the line to being used with standard .303’s for the same purpose, similar to a ‘rod grenade’ but this seems to be much more practical.
https://www.rifleman.org.uk/Enfield_Rifle_Grenades_and_Dischargers.html
In the link above, there is a photo of an exact copy of the rifle under discussion, complete with a red painted magazine.
It’s listed as a carbine version primarily for smoke or signalling projectiles although HE could be used as well. Whether or not that is a 100% accurate description is open for conjecture but it does seem idential to the original ‘Burns cup discharger’ pictured along with it.
Unfortunately, neither the picture nor the text accompanying it is copyable so can’t be pasted here.