37mm Littlejohn

[SG500]

I do like a challenge - got this one last week for the right price.
May take a while!
Its quite unusual in that its a 37mm littlejohn.
Also show is a decent one in my collection that shows what it would have been like before it was left in the ground for many many years.
I should have taken a photo first, it started as a lump of rust.
Now most of the rust is gone so on to stage 2........... I'll keep you posted!
Dave.

 

[SG500]

All INERT of course.
Dave.

 

[HAZORD]

Nice stuff Dave.

Hey, you have written about "LittleJohn" rounds in the past. WHat designates it to be a "LittleJohn"? Is it the specific design of projectile? If so, what are the required characteristics to make it fall into the "LittleJohn" catagory?

Thanks,

John

 

[RichardB]

Hi John,
I believe Littlejohn is a direct translation of Janacek, a Czech designer of this type of projectile

The primary characteristic of the projectile is that it is a squeezebore, ie it fired down a barrel that is tapered, in the same way as the German Squeezebore rounds, such as the 28/20 PzB41. The only difference to the German 28/20 is that the 2Pdr and 37mm Littlejohn rounds utilise a tapered adapter on the end of a standard 2Pdr or 37mm barrel. (...which subsequently negated the use of standard projectiles !!)

I hope that helps a bit, Im sure Dave or a few others can provide more information.

Dave: I assume this is in the restoration section as you proposed returning to its original appearance...looking forward to the results

Cheers, Rich

 

[SG500]

Hi John,
I believe Littlejohn is a direct translation of Janacek, a Czech designer of this type of projectile

The primary characteristic of the projectile is that it is a squeezebore, ie it fired down a barrel that is tapered, in the same way as the German Squeezebore rounds, such as the 28/20 PzB41. The only difference to the German 28/20 is that the 2Pdr and 37mm Littlejohn rounds utilise a tapered adapter on the end of a standard 2Pdr or 37mm barrel. (...which subsequently negated the use of standard projectiles !!)

I hope that helps a bit, Im sure Dave or a few others can provide more information.

Dave: I assume this is in the restoration section as you proposed returning to its original appearance...looking forward to the results

Cheers, Rich

Yes I'm going to have a go but it may all go wrong. Don't expect results too fast though.
Dave.

 

[SG500]

Nice stuff Dave.

Hey, you have written about "LittleJohn" rounds in the past. WHat designates it to be a "LittleJohn"? Is it the specific design of projectile? If so, what are the required characteristics to make it fall into the "LittleJohn" catagory?

Thanks,

John

Thanks John. I've e mailed you some info on this.
Just to add to what Rich has already said:

Frantisek Karel Janecek was born in Prague in 1904. He visited Britain in 1938 to try and sell the anti tank rifle that he had developed.
The first weapon was a .303 version. Several types of rounds were developed by Kynoch including 11/7.92mm and 15/11mm rounds.
In 1941 it was decided to develop the 2 pounder Janecek.

The two pounder "littlejohn" name is merely the English interpretation of the Czeck work "Janecek".

As well as the mk 1 and mk 2 AP versions of the 2 pounder littlejohn I am also aware of the following:-
Several types of 20mm littlejohn (known from specimens)
37mm littlejohn (known from a specimen)
2 pounder HE littlejohn(known from a specimen)
S gun 40mm littlejohn (known from an article on Tony Williams web site)
Bofors 40mm littlejohn(known from a specimen)
47mm littlejohn (known from a specimen)
6pr6cwt littlejohn(known from a specimen)
6pr7cwt littlejohn (known from a specimen)
17 pounder littlejohn (known from a design drawing and the flat head proof version from a specimen)

As Rich says, the taper part was a screw adaptor at the end of the barrel. I've read that some of the gun crews didn't always want to mess around screwing on adaptors in the heat of battle so sometimes just fired the littlejohn rounds without the adaptors in place - the performance was good, the projectiles merely acting like an arrownhead round instead i.e. good short range performance that rapidly tailed off at greater ranges due to poor wind resistance characteristics of the unsqueezed projectile.

Dave.

 

[HAZORD]

Thanks RichardB and Dave, great info!

 

[SG500]

Stage 2 - the filler

I think I may have put too much on here!

Dave.

 

[SG500]

Stage 3 - sanding done

This was easier than I expected - after a rough sand I realised the tracer fitted in the drill bit. I got it spinning very slowly and the finish was easy with 1500 emery cloth.

 

[Chris 42 RQ]

Nice one !

Looking very promising SG500 !

Stroke of luck being able to put into the old Black and Decker !

 

[US-Subs]

Thanks John. I've e mailed you some info on this.
Just to add to what Rich has already said:

Frantisek Karel Janecek was born in Prague in 1904. He visited Britain in 1938 to try and sell the anti tank rifle that he had developed.
The first weapon was a .303 version. Several types of rounds were developed by Kynoch including 11/7.92mm and 15/11mm rounds.
In 1941 it was decided to develop the 2 pounder Janecek.

The two pounder "littlejohn" name is merely the English interpretation of the Czeck work "Janecek".

As well as the mk 1 and mk 2 AP versions of the 2 pounder littlejohn I am also aware of the following:-
Several types of 20mm littlejohn (known from specimens)
37mm littlejohn (known from a specimen)
2 pounder HE littlejohn(known from a specimen)
S gun 40mm littlejohn (known from an article on Tony Williams web site)
Bofors 40mm littlejohn(known from a specimen)
47mm littlejohn (known from a specimen)
6pr6cwt littlejohn(known from a specimen)
6pr7cwt littlejohn (known from a specimen)
17 pounder littlejohn (known from a design drawing and the flat head proof version from a specimen)

As Rich says, the taper part was a screw adaptor at the end of the barrel. I've read that some of the gun crews didn't always want to mess around screwing on adaptors in the heat of battle so sometimes just fired the littlejohn rounds without the adaptors in place - the performance was good, the projectiles merely acting like an arrownhead round instead i.e. good short range performance that rapidly tailed off at greater ranges due to poor wind resistance characteristics of the unsqueezed projectile.

Dave.

Which would this be, MK 1 or MK 2? I've had it banging around on the shelf for some years now, but have few ref docs on non-CW UK projos. It is 40mm in diameter, marked as AP 2PR SV II.

 

[Quatermass]

The Mk 1 projectile is constructed on the same basic principles as the Mk 2, but lacks the nose pad, nose cap and ballistic cap. The core, which is tungsten carbide, weighs approximately 6 ozs. The No. 15 tracer is screwed into the projection in the base of the rear driving band and projects beyond the base of the projectile. The nose ring is the only component incorporated exclusively in the projectile. It is designed merely to facilitate the assembly of the front band.

Source: RAC training Vol. III - Armament Daimler Armoured Car Mks 1 and 2 1951

 

[US-Subs]

So mine is a MK 1......?

 

[Quatermass]

Yes, its a Mk 1! Could yours be marked ' AP 2PR SV IT' rather than 'AP 2PR SV II'?

 

[SG500]

Thanks Chris, yes its getting there.
Dave.

 

[SG500]

So mine is a MK 1......?

Yes its definitely Mk 1.
If you go the the following link the 4th one down on the right shows the Mk 1 and the Mk 2. Another difference between the two is that with the Mk 1 the front flange squeezes forwards, with the Mk 2 it squeezes backwards (note the differing positions of the groove next to the flange).
Nice projectile, the Mk 1's seem to be harder to find than the Mk 2 ones.
Dave.

http://www.bocn.co.uk/vbforum/47mm-littlejohn-bofors-t29760.html?t=29760&highlight=littlejohn

 

[SG500]

Stage 4 - painting done

Stage 4 worked out quite well, now I've just got to put some bands and lettering on it.

 

[Gspragge]

What was the penetration of these ?

versus the regular shot , were they any better than the Discarding sabot types. The screw on adapter being a negative I would think, and I guess doomed the design in the end.

 

[SG500]

Gordon, I don't know about a direct comparison of the 37mm or the 2 pounder littlejohns with equivalent APDS rounds because neither of these guns had apds rounds to compare them with so I've no idea regarding penetration of the round into armour.
The crews sometimes fired the littlejohn rounds from guns WITHOUT the adaptor screwed on the end so the projectile just functioned as an arrowhead type round. At short range they worked very well but performance dropped off at longer range due to the poor aerodynamics of the non squeezed projectile. Clearly at longer range the better shape of the cored part of the APDS projectile would ensure it performed better.
Perhaps someone out there has some theoretical figures on this?
Dave

 

[Tony Williams]

As well as the mk 1 and mk 2 AP versions of the 2 pounder littlejohn I am also aware of the following.

I have seen a Vickers factory drawing dated 1947 (IIRC) which shows a 6-inch gun Littlejohn shell designed to be squeezed down to 4.5". Shell weight 50 lbs. I presume this was intended for an AA gun, although the drawing contained no information about that.