Bloke on the Range videos

One day I'll beg, buy borrow or steal a slow motion camera and take the API in subguns myth on. Interestingly, Turpin is convinced his design API's, but I suspect that if I set up my STEN Mk.II and fire it with both dummies and live rounds, we won't be able to witness the alleged phenomenon.

Although saying that, some of the RUAG ammo has soft, uncrimped primers which get utterly munched (tested in both a STEN and MP40) which does suggest they're igniting before they're fully supported. I can't find the photos back, but I posted them on FB a while back.
A modern trend in submachine guns is to use a hammer or striker fired mechanism to allow firing from a closed bolt for increased accuracy when firing single shots. These submachine guns don't seem to have a bolt which is noticeably heavier than ones which fire from an open bolt with a fixed firing pin.

For that matter, the American civilian recreational market has a fair number of conversions of submachine guns from open bolt to closed bolt so they can sell them as semi-automatic weapons and not need to be registered as "machine guns" under American law. From the limited amount that I have seen, this does not require increasing the bolt mass or spring.

So far as I am aware, the main reason that many submachine guns, especially older ones, fire from an open bolt with a fixed firing pin is because it's cheaper to build them that way.

This would make an interesting "myth-busting" episode, but I'm not sure how you could test it using an unmodified Sten.
 

Chicken

Old-Salt
I know I had a box of the Nato ammo marked as unsuitable for nice guns.

The PK ammo is pretty hot,some people have shot it in Sig p210s with stiffer springs but it's better suited to CG's and MP5s.
20191211_071927.jpg
 
So far as I am aware, the main reason that many submachine guns, especially older ones, fire from an open bolt with a fixed firing pin is because it's cheaper to build them that way.

This would make an interesting "myth-busting" episode, but I'm not sure how you could test it using an unmodified Sten.
Yup. Massively simpler to make.

As for testing it, err, I'll have to think about that. Possibly looking at bolt velocity fired from an open bolt, or with the bolt carefully lowered onto a live round and then the cocking handle gently tapped to make it go bang.
 
Yup. Massively simpler to make.

As for testing it, err, I'll have to think about that. Possibly looking at bolt velocity fired from an open bolt, or with the bolt carefully lowered onto a live round and then the cocking handle gently tapped to make it go bang.
Does the bolt hit the back of the receiver on the Sten, or does the spring stop it before it bottoms out? If it normally hits the back of the receiver, then I'm not sure what that test would prove. It it stops on the spring before bottoming out, then you could measure how far back the bolt goes in each case with a sliding indicator. However, I suspect that you will get objectors who will say that whatever you tap the handle with will have added mass and resistance to the bolt, invalidating the test.

Alternatively, does the bolt face make a clear, flat surface, metal on metal contact with the back of the breech? If so, can you try applying some toolmaker's bluing to the bolt face or breech face to see if it leaves a witness mark on the contacting surface? If advanced primer ignition actually has an effect on the cycle, then the bolt and breech faces should not come in contact and there should be no witness mark. If there is a witness mark, then the bolt and breech faces clearly must have come into contact with one another, meaning the bolt stopped on contact with the breech (and so no API effect on the cycle).

Lack of a witness mark though may not be meaningful, as the contact may have been so brief that it didn't transfer due to some obscure reason of physics. Presence of one though should be evidence of direct contact, unless residual gas blowing out the back happens to spray the bluing off the breech face all over. It might be best to try applying it both ways in separate tests to check for this.

The above is of course predicated on having suitable surfaces on which to apply the toolmaker's bluing.
 

HE117

LE
I'm not sure about this, but I seem to recall reading that the Sterling had two different bolts and springs which could be changed as required. One was for 9mm with SMG loading, and the other was for regular 9mm as used in pistols. If you used the wrong bolt and spring combination for the ammunition type, then either it wouldn't have enough energy to fling the bolt back far enough to reach the sear, potentially leading to a malfunction of some sort, or it would have too much energy, leading to the bolt opening too soon and to the potential for burst cases.

If that is correct, do you know which bolt and spring you had in it? Or is my recollection of this incorrect?
Ok.. I have been in contact with the "horses mouth" from Sterling! He recalls that there was a significant issue with non standard ammunition in the seventies, sparked no doubt by the Indian 9mm..

The SMG was designed to fire UK 2z and, although trials were done, it was decided that making a lighter bolt or spring would be dangerous if the gun was subsequently used with 2z. There apparently were particular issues with Canadian 9mm which was loaded with Bullseye.

The Indian 9mm was not just underpowered, it was also extremely variable!
 

HE117

LE
Does the bolt hit the back of the receiver on the Sten, or does the spring stop it before it bottoms out? If it normally hits the back of the receiver, then I'm not sure what that test would prove. It it stops on the spring before bottoming out, then you could measure how far back the bolt goes in each case with a sliding indicator. However, I suspect that you will get objectors who will say that whatever you tap the handle with will have added mass and resistance to the bolt, invalidating the test.

Alternatively, does the bolt face make a clear, flat surface, metal on metal contact with the back of the breech? If so, can you try applying some toolmaker's bluing to the bolt face or breech face to see if it leaves a witness mark on the contacting surface? If advanced primer ignition actually has an effect on the cycle, then the bolt and breech faces should not come in contact and there should be no witness mark. If there is a witness mark, then the bolt and breech faces clearly must have come into contact with one another, meaning the bolt stopped on contact with the breech (and so no API effect on the cycle).

Lack of a witness mark though may not be meaningful, as the contact may have been so brief that it didn't transfer due to some obscure reason of physics. Presence of one though should be evidence of direct contact, unless residual gas blowing out the back happens to spray the bluing off the breech face all over. It might be best to try applying it both ways in separate tests to check for this.

The above is of course predicated on having suitable surfaces on which to apply the toolmaker's bluing.
Given the stop at the back of both the STEN and the Patchett/Sterling is not particularly strong, I would be most surprised and/or concerned if the back of the bolt made contact...

I have a feeling that the cocking handle slot is too short to allow it to happen anyway..?
 
Ok.. I have been in contact with the "horses mouth" from Sterling! He recalls that there was a significant issue with non standard ammunition in the seventies, sparked no doubt by the Indian 9mm..

The SMG was designed to fire UK 2z and, although trials were done, it was decided that making a lighter bolt or spring would be dangerous if the gun was subsequently used with 2z. There apparently were particular issues with Canadian 9mm which was loaded with Bullseye.

The Indian 9mm was not just underpowered, it was also extremely variable!
As an FYI: I recall that the semi-auto, civilian market, Sterling was a closed bolt contraption.
 
Given the stop at the back of both the STEN and the Patchett/Sterling is not particularly strong, I would be most surprised and/or concerned if the back of the bolt made contact...

I have a feeling that the cocking handle slot is too short to allow it to happen anyway..?
I can tell you that in both of my STENs it does hit the back with factory 115 and with NATO ball, but usually not with factory 124.

What actually is the stop is not only the fairly substantial metal cup that the end of the spring goes into, but the mounting plate for the buttstock which engages in a groove. It's very substantial!
 
 

HE117

LE
As an FYI: I recall that the semi-auto, civilian market, Sterling was a closed bolt contraption.
I'm seeing him tomorrow.. I will find out!
 

4(T)

LE
As an FYI: I recall that the semi-auto, civilian market, Sterling was a closed bolt contraption.

Yes, it had a slotted bolt with a floating firing pin and spring inside, The end of the firing pin had a hook that was caught by a sear in the trigger group. Apart from this extra sear, the trigger group differed from the military/auto standard version by having (IIRC) a fixed disconnector - ie couldn't be altered by changing the safety position.

IIRC the carbine bodies also had a steel rod in the bottom of the tube that ran in the slot of the semi-auto bolt, but would block a full-auto bolt.

I've heard that there was an informal attempt by certain armourers to get the civilian carbine trigger group to work in a military gun - ie produce a closed bolt full/semi auto L2A3 - but it didn't go anywhere.
 
I can tell you that in both of my STENs it does hit the back with factory 115 and with NATO ball, but usually not with factory 124.

What actually is the stop is not only the fairly substantial metal cup that the end of the spring goes into, but the mounting plate for the buttstock which engages in a groove. It's very substantial!
I believe that was a problem during the Heydrich assassination as they fired their Stens without the butt stock on (for concealment) so the gun fell to bits after a few rounds.
 
I believe that was a problem during the Heydrich assassination as they fired their Stens without the butt stock on (for concealment) so the gun fell to bits after a few rounds.
The Sten was full of grass, which caused the jam.

The Czechs had taken to keeping rabbits as a way of supplementing their rations. It wasn't unusual to see Czechs picking grass and putting it in their bags, handbags etc to take home for their rabbits.

The bag containing the Sten also contained grass, which caused it to jam.
 

ugly

LE
Moderator
The Sten was full of grass, which caused the jam.

The Czechs had taken to keeping rabbits as a way of supplementing their rations. It wasn't unusual to see Czechs picking grass and putting it in their bags, handbags etc to take home for their rabbits.

The bag containing the Sten also contained grass, which caused it to jam.
It wasn’t fitted with a butt! That was the first and worst problem after this SOE had buttless pistol grips made to allow the stems to be fired after this
 
OK, there are 3 stories I've read regarding the STEN jam in the Heydrich assassination:

1. It just failed to fire, probably due to a crap mag (the generally-accepted version).
2. Hid in a wheelbarrow full of grass, which caused the jam (book that El Chappo leant me)
3. Fired with the butt off, which caused the retaining ring to fail (Peter Laidler's Collector Grade book).

Which is true, I have no idea. 1 and 2 are plausible (although going into action with an untested mag is Bad Drills, which speaks against 1). 3 is plausible if 1 or more shots were fired, and I believe that other reports suggest that no shots were fired. It's the bolt coming back from a shot that would cause the retaining ring to fail, so at least one shot would have been fired if this were the case.
 
OK, there are 3 stories I've read regarding the STEN jam in the Heydrich assassination:

1. It just failed to fire, probably due to a crap mag (the generally-accepted version).
2. Hid in a wheelbarrow full of grass, which caused the jam (book that El Chappo leant me)
3. Fired with the butt off, which caused the retaining ring to fail (Peter Laidler's Collector Grade book).

Which is true, I have no idea. 1 and 2 are plausible (although going into action with an untested mag is Bad Drills, which speaks against 1). 3 is plausible if 1 or more shots were fired, and I believe that other reports suggest that no shots were fired. It's the bolt coming back from a shot that would cause the retaining ring to fail, so at least one shot would have been fired if this were the case.
I don't think that anyone actually knows for sure, unless a German report has come to light which analysed the situation in detail.If there is one, I haven't heard of it. Nobody else is in a position to say for sure, as the assassins themselves were in no position to report on it and the details of the operation were left to the Anthropoid team to decide for themselves after they arrived in Czechoslovakia.

The book that I have, "The Killing of SS Obergrupppenfuhrer Reinhard Heydrich" by Callum MacDonald simply states:
Both men carried battered briefcases. Inside, concealed under layers of grass, were the sten gun, broken down into three pieces, and two fused bombs. The grass was intended to camouflage the weapons from a casual police check. Since the food shortages of 1941, many Czechs had started to breed rabbits and it was not unusual for citizens to collect food for their animals in the local parks. They wore caps to conceal the colour of their hair and, despite the fine weather, Gabcik carried a light-coloured raincoat borrowed from a neighbour. The coat was necessary to hide his hands while he was assembling and holding the sten gun. (...)

Gabcik knelt down, opened his briefcase and put the sten together under cover of his coat. He did not have to see what he was doing. Assembling guns blindfold was a standard part of weapons training, a drill he had taught many times to the soldiers of the Czech Brigade. With the coat draped casually over his arm, he crossed the street and stood beneath a small knoll near a tram stop, waiting for Valckik's signal. (...)

As Heydrich's car slowed down and rounded the corner, Gabcik dropped the raincoat, raised his gun and, at point-blank range, pulled the trigger. Nothing happened. The sten failed to fire, either because it had been badly assembled or more likely because there was grass jammed in the mechanism.
The raincoat was borrowed from a neighbour near where the assassins were staying.

I've seen this photo which is claimed to be the sten abandoned at the site, but I can't verify if it is genuine or if it comes from a later movie or re-enactment. It does show the sten without a butt stock. I don't see the innards hanging out the back however so this doesn't tell us much.


Here's the recently declassified CIA secret report on Anthropoid, which the Americans call "Operation Salmon" for some reason. It's rubbish in general, offers no real useful information on the assassination itself, and I wouldn't put much faith in anything in it. It seems to have been written some time after the war, although it's not clear when exactly. If the American CIA had any knowledge of what exactly happened it's not in this report.
The Assassination of Reinhard Heydrich

It would seem rather odd though to have planned everything so meticulously but to not have practised firing the sten with the stock removed during training. For that matter,
it's a bit unclear whether Gabcik could actually have hit anything this way even if the gun functioned correctly. With only one hand having a good grip I suspect the gun might have been uncontrollable after the first shot. That might be a good subject for experiment if it is possible to arrange, and if it wouldn't violate Swiss firearms laws (making the gun operable without a stock).
 
I don't think that anyone actually knows for sure, unless a German report has come to light which analysed the situation in detail.If there is one, I haven't heard of it. Nobody else is in a position to say for sure, as the assassins themselves were in no position to report on it and the details of the operation were left to the Anthropoid team to decide for themselves after they arrived in Czechoslovakia.

The book that I have, "The Killing of SS Obergrupppenfuhrer Reinhard Heydrich" by Callum MacDonald simply states:


The raincoat was borrowed from a neighbour near where the assassins were staying.

I've seen this photo which is claimed to be the sten abandoned at the site, but I can't verify if it is genuine or if it comes from a later movie or re-enactment. It does show the sten without a butt stock. I don't see the innards hanging out the back however so this doesn't tell us much.


Here's the recently declassified CIA secret report on Anthropoid, which the Americans call "Operation Salmon" for some reason. It's rubbish in general, offers no real useful information on the assassination itself, and I wouldn't put much faith in anything in it. It seems to have been written some time after the war, although it's not clear when exactly. If the American CIA had any knowledge of what exactly happened it's not in this report.
The Assassination of Reinhard Heydrich

It would seem rather odd though to have planned everything so meticulously but to not have practised firing the sten with the stock removed during training. For that matter,
it's a bit unclear whether Gabcik could actually have hit anything this way even if the gun functioned correctly. With only one hand having a good grip I suspect the gun might have been uncontrollable after the first shot. That might be a good subject for experiment if it is possible to arrange, and if it wouldn't violate Swiss firearms laws (making the gun operable without a stock).
I'd not seen that photo before, interesting.

I could certainly arrange firing without the stock, though to avoid damage to the gun I'd have to put a stock interface blanking plate in there. My Mk.2 is semiauto however... Would give me an excuse to seek out a full auto one though to add to the collection :p
 
I'd not seen that photo before, interesting.

I could certainly arrange firing without the stock, though to avoid damage to the gun I'd have to put a stock interface blanking plate in there. My Mk.2 is semiauto however... Would give me an excuse to seek out a full auto one though to add to the collection :p
I think that you would indeed need to put a plate in the back of the receiver for Operation Blokethropoid, as even if there were no risk of damage to the Sten it wouldn't be very useful from a test perspective if the Sten were to fall apart in the middle of a test.

I think that a test in semi-auto would be quite useful just in terms of whether you can actually hit anything with it. You could for example estimate the appropriate range and then set up a chest and head sized target (simulating Heydrich seated in an open car). Start with the gun down by your side (as this is how Gabcik was waiting), then on signal quickly raise it and fire three shots in rapid succession and see where the shots went. Repeat this several times, each time giving yourself only a brief exposure time. Then, repeat the test with the stock for comparison, and possibly again using a pistol. It sounds like something you might be able to do on a pistol range in a sort of timed shoot.

And remember, practice is cheating, especially within the context of what we are talking about where we are assuming that firing the Sten in this configuration was a last minute decision by someone who would not have had a chance to practice using it this way.

Trying this in full auto is something that could come later, after you have established whether this is both practical and safe.

This would be a nice history-themed test, and would probably be more tangible to people if you gave a very brief description of where the original event fit into the historical background of one of the most audacious and successful special operations of WWII.
 
I think that you would indeed need to put a plate in the back of the receiver for Operation Blokethropoid, as even if there were no risk of damage to the Sten it wouldn't be very useful from a test perspective if the Sten were to fall apart in the middle of a test.

I think that a test in semi-auto would be quite useful just in terms of whether you can actually hit anything with it. You could for example estimate the appropriate range and then set up a chest and head sized target (simulating Heydrich seated in an open car). Start with the gun down by your side (as this is how Gabcik was waiting), then on signal quickly raise it and fire three shots in rapid succession and see where the shots went. Repeat this several times, each time giving yourself only a brief exposure time. Then, repeat the test with the stock for comparison, and possibly again using a pistol. It sounds like something you might be able to do on a pistol range in a sort of timed shoot.

And remember, practice is cheating, especially within the context of what we are talking about where we are assuming that firing the Sten in this configuration was a last minute decision by someone who would not have had a chance to practice using it this way.

Trying this in full auto is something that could come later, after you have established whether this is both practical and safe.

This would be a nice history-themed test, and would probably be more tangible to people if you gave a very brief description of where the original event fit into the historical background of one of the most audacious and successful special operations of WWII.
That's probably possible. Off the top of your head, any idea what the engagement range was in reality?
 
OK, there are 3 stories I've read regarding the STEN jam in the Heydrich assassination:

1. It just failed to fire, probably due to a crap mag (the generally-accepted version).
2. Hid in a wheelbarrow full of grass, which caused the jam (book that El Chappo leant me)
3. Fired with the butt off, which caused the retaining ring to fail (Peter Laidler's Collector Grade book).

Which is true, I have no idea. 1 and 2 are plausible (although going into action with an untested mag is Bad Drills, which speaks against 1). 3 is plausible if 1 or more shots were fired, and I believe that other reports suggest that no shots were fired. It's the bolt coming back from a shot that would cause the retaining ring to fail, so at least one shot would have been fired if this were the case.
I had a blank fire & non gun each one after about 10 demo's cocked and just stopped working, a FS and oiling sorted it
Screenshot_2019-12-15-10-08-15(1).png
 
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