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British WW1 No 20 Mk 1 Rifle grenade


Well-Known Member
Premium Member
Hi there,

would any of you grenade experts out there have any pictures of the dissassembled parts for a No 20 Mk 1 rifle gren from WW1?

i am currently restoring one and have got it into pieces as best i can and wonder if the central tube that contains the firing pin and creep spring should also come apart from the brass body it sits in? its dated august 1916 and made by G.T.L whoever they are.

Everything is now is now highly polished and finger tight, just need to clean and paint the body.


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Hi Andy, I don't have my stuff to hand here, but I'm sure Paul or someone else can help with a pic of all the bits. The brass tube should come out of the top and base, but not worth forcing it as they are thin and fragile. Tony.
No 20 Mk I

Hope this drawing is of some help.


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Thanks Tony & Norman,

think i have got it as dismantled as it needs to be, now just thinking about a repaint.

Hi Andy

The maker GTL is actually Gastetner. The company that used to make the old duplicators. I've not got a 20 but have a 3, a 24Mk1 a 24 Mk2 and a 35. I think the 20 was most similar to the No3 inside. Certainly parts are generally interchangeable and there were a number of official hybrids made that often had No 20 caps but were mainly made from No 3 parts. So they look like a 3 but have 20 on the top. Possibly the most confused grenade of WW1, which was why they made the 24 and later the 35. Have a look at Landers' descriptions for all the variants of the 3.

Here you are Dano,

a couple of pics as it is now. Completely unscrews easily, just needs to be painted yellow with a red and pink band. Will do this in a few weeks and post another piccy then.



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Heres 3 for your enjoyment lads!
top one has its original paint, middle is a drill stripped down to all its parts and bottom one sectioned by me.
Cheers, Paul.


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Ansome Paul,

seems like i am missing the tube from the filler screw at the top of the gren that fits into the central tube the needle pellet fits into, just got the threaded screw. However, this cant be seen so ime still happy. Probably was damaged in the deac process. Thanks for the pics.

I am currently restoring a No20 (well i think it is) which i bought a few years ago and only recently got around to looking at...
Any way I am a little confused.

All the no20s i have seen have no Hales muzzle clips however mine has two screw holes one of which still has a sheered off screw inside.

The only Stamp marks it has is a Triangle on the Base Piece and GTL on the top.
The Rifle rod was broken off about 5cm from the bottom of the base so this has been carefully removed.

Can some one please verify this as a No20 or a reworked No3?
Should it have a hales clip?
The corded loop on the pull pin what was this made from?


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No 20 Converted Mks I & II

It is not unusual to find the base on a No 20 Mk I with holes drilled for a muzzle clip. It is unusual to find the remains of a screw in the threads however.

In most cases the base piece was clearly (in my view) manufactured for a No 3 but used for new manufacture No 20s by turning the base piece down to the shape required. Yours is one of these.

There were two conversions of the No 3 into No 20s. The Grenade, .303-inch Rifle, No 20, Converted, Mark I is unmistakeably a modified No 3 Mark I with a special releasing collar or socket which has slits only at one end. The base pieces are not modified. As far as I remember (no documents to hand) the Converted Mark II (From a No 3 Mark II) has a similar although slightly longer collar.

The becket is made from 'Tarred whipcord'.

Found image of Converted Mk I and drawing of Converted Mk I and Mk II although the releasing collar details are not visible in the dwg.


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Hi Bonnex,
Thanks for the information.
My Release collar is slotted from both ends but seems fairly long.
I will measure it tonight when I get home, what is the normal length for this collar?
Hi Bonnex,
Is that for the normal no20 or the longer no20 converted. my release collar measures about 1.36"
Hi Bonnex,
Is that for the normal no20 or the longer no20 converted. my release collar measures about 1.36"

That's for the regular No 20 Mark I. I have never seen a No 20 Converted Mk II, which is a modified No 3 Mark II. I have only seen the drawing.
Hi Grenadair,
How long is your slotted release collar?
I assume the base has the two holes where the hales clip was ment to go?


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