Squeezebores from other countries

[SG500]

There's a good thread running about German squeezebores so I thought it was time to try and consolidate photos I've posted in various threads into one post in the hope others could share photos of their squeezebores. I use the term fairly loosely, in the UK they were referred to as littlejohns, elsewhere cone bore, the ones I'm showing are projectiles that get squeezed as the go down the barrel and exit with a far smaller diameter than they started.........so at the risk of boring you guys here goes, I hope you enjoy the photos, oh and if anyone has any spares in their collection I'd be glad to buy/swap:tinysmile_fatgrin_t................


20mm mystery.
This came from a Swedish collection, I know nothing about it but am of the opinion its real. Its made out of different parts with the flanges being put on separately.
Anyone any ideas?


37 x 222
The photos show a 37 x 222 unfired projectile next to a fired one next to a fired sectioned one.


40mm (2 pounder)
Two 2 pounder mark 2 littlejohns, one in section and one complete. These are the most common types out there (they're still hard to find).


40mm (2 pounder) and 40mm Bofors littlejohn. Both fitted with Mk 1 projectiles.
If it wasn't for the provenance of the Bofors I'd have said it was a made up round BUT a Bofors littlejohn was made and tested. Shown next to a mk 1 two pounder littlejohn for scale.


Swiss 47mm.
I don't have any more information on this one, any help appreciated.


Jones and Lamson 57mm (USA).


6 pounder 6cwt


17 pounder
I think this is a 17 pounder flat head proof littlejohn. Its been fired without the attachment. I know of 1 other identical one in another collection.


All together
A group photo to show the scale of the different rounds.


ALL re INERT.

Dave.

 

[HAZORD]

Really nice stuff Dave!

Hey, I have a question. What is the exact definition of squeeze bore? The reason I ask, is because recently US-subs posted a photo of a 3 inch 70 projo, that is a probert design. So are the 3.7 inch probert and 3 inch 70 cal probert projectiles considered a squeeze bore projos?

 

[SG500]

Really nice stuff Dave!

Hey, I have a question. What is the exact definition of squeeze bore? The reason I ask, is because recently US-subs posted a photo of a 3 inch 70 projo, that is a probert design. So are the 3.7 inch probert and 3 inch 70 cal probert projectiles considered a squeeze bore projos?

Thanks John.
According to Ian Hogg in his book "The Illustrated Encyclopedia of Ammunition" a squeezebore is a "type of gun in which the diameter of the barrel is suddenly reduced at some point along the bore so that the diameter of the projectile is similarly reduced". In the case of German ammunition the barrel reduced along its length so it was in effect a cone hence the wording "cone bore", in the case of most if not all of the ones shown on this thread the shell was fired along the barrel at full bore and then passed through a non rifled adaptor screwed to the end of the barrel, in the case of the British ones it was the littlejohn adaptor, the adaptor squeezed the flanges into the recessed parts of the body so the projectile emerged with no clear rifling on it.
With the Probert driving bands shown on US-subs recent thread they work in a different way and the bore of the gun does not reduce along its length. Ian Hogg in his book "British and American Artillery of World War 2" describes the rifling on the 3.7 inch mk 6 as follows: "Since a high velocity was demanded a new system of rifling was proposed. Known as "RD" (Research department) Rifling, it was designed by Colonel C.O.C, Probert of that Department and it worked in conjunction with a specially designed shell. The rifling commenced at zero depth and the lands gradually assumed their full height at just over four inches from the commencement of rifling. Towards the muzzle the groove depth gradually reduced until at 11 inches from the muzzle the bottom of the grooves had come up to meet the top of the lands and the gun was a smooth bore. The shell was fitted with a high efficiency driving band and twin centring bands at the shoulder. These had the effect of dividing the torsional stress of spinning more evenly along the length of the shell and centring the projectile more prefectly on the axis of the gun barrel. As the rifling grooves decreased, the copper of the driving and centring bands was squeezed into the cannelures in the shell body, and on leaving the muxxle these coppper bands which normally protruded into the air stream and degraded the shells flight were smoothed flush with the shell wall to permit the unbroken air flow over the shell which helped to sustain the velocity."
So to answer your question, its all a bit grey, both systems squeeze the projectile, I would interpret it that the flanged squeezebores reduce in diameter significantly as they pass down the barrel which is itself coned at come point, with the Probert system the actual projectile is not reducing in diameter, only the copper driving bands.
Dave.

 

[EOD]

Dave, thanks a lot for the awesome images!

 

[hasag]

These shells are there?, jejej
you wonder, here in Spain hurts not come ...
Happy new year

 

[SG500]

Thanks for the feedback guys. Hasag I am not sure what you are trying to say, sorry.

Dave.

 

[hasag]

I meant that these projectiles are fantastic
That here in Spain never saw them.
What luck you have.
a greeting
and Happy New Year

 

[SG500]

I meant that these projectiles are fantastic
That here in Spain never saw them.
What luck you have.
a greeting
and Happy New Year

Thank you, I understand now.:tinysmile_grin_t:
Dave.

 

[SG500]

Hi guys, help me out here please, does anyone else have photos of similar rounds they can post?
Has anyone got the super elusive 6pr 7cwt littlejohn or even some of the small calibre rounds that were made?
Dave.

 

[ordnance]

Dave,

This should be some useful information if you haven't seen it before. I borrowed a copy of a report on U.S. Development of squeezebore and HVAP ammunition in WWII from a friend recently. I finally scanned the images tonight and added a few here. All of the images can be seen here:

http://imageevent.com/ricklarson/usgerlichdevelopment

I hadn't realized that the U.S. Army began such development before our entry in WWII, based on a German 28/20mm gun and ammunition captured at Halfaya Pass in 1941. Our first gun was a 28/20 T5 barrel assembly fitted to a 37mm M4 gun carriage, starting with sketches made in June, 1941. The cartridge case was the T2, a copy of the German case, and 1098 were produced at Frankford Arsenal by March, 1942. The projectile was designated T6.

When the development moved up to 37mm, the next round was designated "Shot, H.V.A.P. 37/28mm T25". It appears the engineers followed the British Little John work with a tapered muzzle attachment fitted to a straight bore cannon. There was also a 57/40mm project and it appears all of the later WWII high velocity experiments moved away from taper bores in favor of H.V.A.P arrowhead projectiles in straight bores. Hope this is useful for you.

Rick

 

[SG500]

Thanks ordnance, doesn't it make you realise what a wonderful thing the internet can be with all these great original scanned images on there! I've had quite a few of these images for years as photocopies of photocopies hoping one day better copies would surface and there they are, thank you and much appreciated.
Now.........have any of you guys across the pond got any of these nice American experimentals you can post photos of ?? Finding a T2 would be a good result indeed.
Dave.

 

[SG500]

Just a couple of variations from the 1940's, salvo squeezebore rounds.
All INERT/primers oiled etc.
Dave.

 

[TonyE]

As you have shown a couple of the Project Salvo Sqeezebore rounds I thought I would add a bit of history.

These actually date from the late 1950s/early 1960s and much of the work was done by Russell Robinson. His squeezebore patent is at http://www.google.com/patents/about/3450050_SALVO_SQUEEZEBORE_PROJECTILES.html?id=HNByAAAAEBAJ

Russel was an Australian who came to the UK in WW2 and worked at Cheshunt and Enfield during the war and post war periods. He developed among other things a .50 MG for AFVs with a very short receiver to minimise turret intrusion (the EM-1 MG IIRC). He then went to work in the US on Project Salvo and eventually retired to Tucson, Arizona.

I knew Russell and in the mid 1980s he still had his garage filled with boxes of all the different Salvo cartridges. He was a great guy and had a wealth of interesting stories about weapon development. I still see his daughter regularly.

Regards
TonyE

 

[SG500]

Just a few photos to show the 2 pounder before and after it goes through the attachment.
Its surprising how small the core is.
Dave.

 

[apfsds]

FANTASTIC photos Dave! THANKS BIG TIME for posting them!!!

Jason

 

[SG500]

Some photos of a recent acquisition. Its Spanish and was developed by CETME and was intended for an improved version of the Soviet 45mm anti tank gun where it would be fitted with a conical adapter for the barrel. Soviet or Spanish made cases were used and would have a double crimp.

There are no stampings on it, the only markings are some very faint in marks on the base that I can't read.

If anyone has any further information or even a case with the correct crimping please let me know. The last 2 photos show it next to a regular Mk 2 British 2 pounder 40mm littlejohn projectile for scale.

All INERT.

Dave.

 

[SG500]

I picked up a development 20mm Janecek this weekend, doesn't look that exciting but is one that was difficult to find.

Note the correct crimping at the very top of the case.

All INERT.

Dave.

 

[pzgr40]

At the moment I a bussy with a 90 degrees cuaway odf a 37mm squeeze bore projectile as in picture 2of #1. To what shellcase does it belong the 37x223R for the M3 Anti tank gun, or the 37x223 SR shellcase of the M1 AAA. I have seen it on both shellcases, but I want to prevent from looking for and buying the wrong shellcase.
Thanks in advance,
Regards, DJH

 

[RichardB]

Well it definitely belongs in the 37x223R (see picture #1) but i dint know if it was ever used in the SR. we know the 40mm littlejohn was used in the short 2pr (s-gun?) case see picture 2. Note both cases are not the standard case

 

[Tony Williams]

Well it definitely belongs in the 37x223R (see picture #1) but i dint know if it was ever used in the SR. we know the 40mm littlejohn was used in the short 2pr (s-gun?) case see picture 2. Note both cases are not the standard case

You can read about the Vickers S gun with Littlejohn adapter here: http://quarryhs.co.uk/sgun.htm

As far as I know, the only application of the Littlejohn to US 37 mm guns was in light tanks (and I'm not sure that ever entered service), so it would be the rimmed case.