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roncl

Seafire lll - Use of Mk V 20mm Cannon

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I have read that later versions of the Seafire lll LF were equipped with the faster firing, lighter weight and shorter barrel Mk V 20mm cannon in place of the heavier long barrel Mk II 20mm cannon.  The Mk V cannon was 12 inches shorter than the Mk II cannon, and the cannon fairing covering the barrel was noticeably shorter than the fairing covering the Mk II cannon barrel. 

 

Does anyone know when the Mk V cannons were introduced on the Seafire lll and how many Seafire lll’s might have used the Mk V cannon?

 

Finally, does anyone have any good pictures or drawings showing the Mk V cannon installed in the wings of the Seafire lll?

 

Thank you. 

 

 

 

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Ron,

Several references ("The History", Morgan/Shacklady and Warpaint 72, Darling) mentions that the modification to Mk V cannon was introduced early in Seafire III production. No date or serial given, though.

In a crown drawing of the Seafire III installation the Hispano Mk V is identified. This has recently been published on p.221 in Valiant Wings Airframe & Miniature No.12, Spitfire Part 1 (Merlin-powered). The fairing looks much shorter, could possibly be seen in pics of real a/c? (I haven't looked, yet)

Edited by Tomas Enerdal

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AIUI the only significant external difference between the MkII and MkV cannon was the barrel length. So the fittings should be the same for both models.

 

As for which aircraft had the Mark V and / or the rocket fittings, the best I can do is to say that David Brown in "The Seafire - the Spitfire that went to sea" refers to "Late production Seafire L.III" having them. I don't recall any wartime photos of Seafires with them, even in the Pacific in mid-late 1945. All appear to have the long barrels. Shacklady has an undated photo of an Irish Air Corps aircraft (No. 149 ex PX948) with them. That aircraft left the production line in March 1945 but had only reached Ceylon for test by the end of the war, but was refurbished before going to the IAC in Jan 1947, so it might not have had the Mk V fitted when it left the factory.

 

Most MkXV seem to have had the MkV cannon. While production of these started in 1944, it didn't really pick up until March 1945 as Mk III production began to tail off.

 

So if Mk V cannon were also being fitted to Seafire III at the same time you would have to be looking at aircraft in the RX*** serial range (from Westland) or PX***/SP*** serial range (from Cunliffe Owen). Quite a number of these went to the French Navy. A few reached squadrons working up in the UK in summer 1945, but the the major RN users were second line squadrons on the post-war period.

 

I know that my second para is at odds with Thomas', but my reading of Shacklady is different. All that is said is that "Production of the MkIII was increasing and with it many major modifications were being added on the line". These included changing the cannon and provision for rockets. No dates are given, not even an indication of early or late in the production run. We do know that while HMS Implacable's squadrons took rocket rails to the Pacific in early 1945, they were not cleared for use during WW2. The photo evidence of her aircraft does not, to my eyes at least, support the short cannon being fitted.

 

As far as I'm aware the first production aircraft to be fitted with the MkII cannon were the Tempest MkV Srs ii from mid-1944. By that time the Seafire III had been in production for a year.

Edited by EwenS

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Ewen,

Not at odds, really. To quote Kev Darling, p.7: "Even as Seafire III production was continuing major modifications were incorporated as and when possible. One of the first was to introduce  the Hispano Mk V instead of the earlier Hispano Mk II as the former was a lighter weapon that reduced the aircraft's weight." When that would be is not stated.

(I must confess that I didn't read the rather elaborate description in David Brown's book at first).

I vaguely remember a modeling article about Irish Seafires, I'll see if I can locate it.

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I found another reproduction of the pic of Irish Seafires starting with 149. It is printed much smaller but the whole row of planes (7) can be seen. Difficult to determine for sure, but all appear to have short guns.

There is also a booklet about its Aeronavale service, which I don't have, Les Seafire dans l'Aéroanautique navale Francaise.

Edited by Tomas Enerdal

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54 minutes ago, Tomas Enerdal said:

I found another reproduction of the pic of Irish Seafires starting with 149. It is printed much smaller but the whole row of planes (7) can be seen. Difficult to determine for sure, but all appear to have short guns.

There is also a booklet about its Aeronavale service, which I don't have, Les Seafire dans l'Aéroanautique navale Francaise.

I do have that, will give a look and let you know what I find

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Ireland received 12 Seafire LFIII 2-9/47 per Darling's Crowood book. 6* PP serials built 9/44. and 5* PR/RX serial built 12/44-2/45 and one PP915 which is an incorrect serial as it does not relate to Spitfire or Seafire.

 

Most of the PP serials had seen war service on Implacable / Indefatigable in 1945. One PP936 had actually been written off by the RN in March 1945 so is either an another incorrect serial or a rebuild by Supermarine and another is recorded as crashing that same month so requiring repairs. No post-war RN history seems to be available for any of them courtesy of Air Britain.

 

The 5 PR/RX serials are all noted as having been returned to Vickers South Marston factory in 1946/47 for "Refurbishment to F.VC standard" before transfer to Ireland.

 

So plenty of scope for modifications from the factory build standard before they arrived in Irish Air Corps service.

 

More scope I think in looking for an answer in the French aircraft. Darling has 54 LIII going to the French from June 1946, the time when HMS Colossus was transferred as Arromanches. About 2/3rd of these were built after 10/44 and a fair number seem to have spent their RN lives in storage. At least one however was only for spares use. Unfortunately my interest doesn't lie with Aeronavale aircraft so I dont have that French book in my library.

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1 hour ago, EwenS said:

Ireland received 12 Seafire LFIII 2-9/47 per Darling's Crowood book. 6* PP serials built 9/44. and 5* PR/RX serial built 12/44-2/45 and one PP915 which is an incorrect serial as it does not relate to Spitfire or Seafire.

 

Most of the PP serials had seen war service on Implacable / Indefatigable in 1945. One PP936 had actually been written off by the RN in March 1945 so is either an another incorrect serial or a rebuild by Supermarine and another is recorded as crashing that same month so requiring repairs. No post-war RN history seems to be available for any of them courtesy of Air Britain.

 

The 5 PR/RX serials are all noted as having been returned to Vickers South Marston factory in 1946/47 for "Refurbishment to F.VC standard" before transfer to Ireland.

 

I'm afraid the Crowood Seafire book is one of the most shoddily written and poorly edited in my library and the information you provide above does nothing to change my view.  One or two useful photos just about enough to save it from the charity shop.

 

According to Air Britain's Spitfire International, the 12 Irish Seafires were, in order of UK serial number with Irish serial in parentheses;

 

PR302 (146), PR237 (155), PR315 (147)

 

PX915 (154), PX924 (153), PX929 (152), PX936 (156), PX941 (151), PX948 (149), PX950 (148)

 

RX168 (157), RX210 (150)

 

Sturtivant's FAA Fixed Wing Aircraft Since 1946 agrees the UK serials and the correlations to Irish ones.  You'll note that all of Darling's PPxxx serials should be PXxxx.

 

The one photo  (undated) of an armed Irish Seafire in Spitfire International shows 149 (ex PX948): short cannons.

 

 

 

Edited by Seahawk

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1 hour ago, EwenS said:

More scope I think in looking for an answer in the French aircraft. Darling has 54 LIII going to the French from June 1946, the time when HMS Colossus was transferred as Arromanches. About 2/3rd of these were built after 10/44 and a fair number seem to have spent their RN lives in storage. At least one however was only for spares use. Unfortunately my interest doesn't lie with Aeronavale aircraft so I dont have that French book in my library.

Spitfire International reports 142 Seafire III going to the French (plus 15 Seafire F.XV).  From a quick scan of the individual histories these seem to have come from the LR (2), NN (27), PP (2), PR (23), PX (19), RX (43) and SP (17) ranges (yes, discrepancy of 9: probably overlooked by me somewhere!).  Darling has counted many of the L.III serials as F.XVs.  Too many airframes for me to chase through the oeuvres of Sturtivant for previous WW2 service.

 

There is an undated photo of Seafire L.IIIs on the deck of Arromanches.  PR146 54.S-14 has long cannons (also high camo demarcation and A-Type roundels), 1.F-3, 1.F-26 and 1.F-28 have short ones (plus full TSS camo and Type C roundels): from individual histories candidates for 1.F-3 are PR329 and RX166, for 1.F-26 RX254 and 1.F-28 RX220 but NB those records may be incomplete).  In a photo taken around 1950-1, PR397 54.S-22 has long cannons (high camo demarcation but proper Aeronavale roundels).  SP136 (no codes) has short cannons (full TSS and Type C roundels - date 1947).

 

All of which supports your theory that the short barrels were introduced in the PX, RX and SP series.

Edited by Seahawk

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1 hour ago, Seahawk said:

I'm afraid the Crowood Seafire book is one of the most shoddily written and poorly edited in my library and the information you provide above does nothing to change my view.  One or two useful photos just about enough to save it from the charity shop.

 

According to Air Britain's Spitfire International, the 12 Irish Seafires were, in order of UK serial number with Irish serial in parentheses;

 

PR302 (146), PR237 (155), PR315 (147)

 

PX915 (154), PX924 (153), PX929 (152), PX936 (156), PX941 (151), PX948 (149), PX950 (148)

 

RX168 (157), RX210 (150)

 

Sturtivant's FAA Fixed Wing Aircraft Since 1946 agrees the UK serials and the correlations to Irish ones.  You'll note that all of Darling's PPxxx serials should be PXxxx.

 

The one photo  (undated) of an armed Irish Seafire in Spitfire International shows 149 (ex PX948): short cannons.

 

 

 

Just as well I picked it up cheap in a sale, if not in a charity shop. Today’s excuse for the mis-information? Taking a shortcut rather than use the Air Britain books! Never mind. 

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Thanks for the great information everyone!  Very much appreciated! I have seen drawings of the Mk V cannon installed in the Mk XV Seafire, but have not seen any drawings showing the Mk V cannon installed in the Seafire lll.  Tomas, is there any chance you could post a picture of the Mk V cannon in the Seafire III in this thread?

 

The installation of the Mk V cannon in the Seafire lll would make this variant of the Spitfire/Seafire the only one to use the Mk V cannon in World War II.  All other Spitfires used the Mk II Hispano cannons during the war.  I believe the only other aircraft to use the Mk V cannon during the war was the Hawker Tempest.  All other Spitfire/Seafire variants were fitted with the Mk V cannon postwar.  

 

Thanks  again.

 

Roncl

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I gather the Czech Mk.IXs that went home had the short barrels, which suggests that although these were all new aircraft rather than the ones they'd flown in RAF service, there was a good chance that a few could have reached other squadrons before VE Day.  Let alone before the end of war in August, of course...

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21 hours ago, roncl said:

The installation of the Mk V cannon in the Seafire lll would make this variant of the Spitfire/Seafire the only one to use the Mk V cannon in World War II. 

It would be but, unless I've missed something, I'm not sure the evidence takes us that far yet.  We've established that the Mk V Hispano was introduced during the Seafire III production and come up with no evidence against @EwenS's contention that it occurred during the PX, RX and SP serial runs.  We also know that earlier Seafire IIIs may have been fitted with them during refurbishment prior to export.  But I at least have yet seen no evidence that Seafires armed with the shorter gun saw action during WW2.  That they existed seems in little doubt: aircraft in the PX range were ready for collection Feb-Mar 45, the RX range in Jan-Jul 45 and the SP range in Mar-Jul 45 (Sturtivant: FAA Aircraft 1939-45) but there is scant evidence of their making their way through the supply chain to front line units before the end of the war.  So it all depends on what you mean by "use": if you mean "be fitted with", then I would say. "most probably".  If you mean "fire in action" or even "serve with front-line units", I'm afraid I would like photographic or solid documentary evidence.

 

Nor am I sure that there weren't Spitfires with the Mark V Hispano in active front service before the end of the war.  I have seen 74 Sq's Spitfire LF.XVIe rear vision TB675 4D-V (completed around Feb 45) depicted in artwork and models as having the short guns though the one photo I have of this aircraft (Rawlings: Fighter Squadrons of the RAF, p.187, taken at Drope, April 1945) is from an angle that doesn't show the cannon.  As it was of a similar vintage to the Spitfires given to Czechoslovakia, I would consider it a good candidate for the shorter guns but don't have the evidence to make any more positive assertion than that.

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roncl

Your question has piqued my curiosity about this. So sitting in front of the TV last night I ran a few internet searches. I was surprised to see that you had posted a similar question about the Spitfire on another site way back in 2007. Unfortunately you got no response then.

 

Given that you must have found some information about Spitfire usage of this gun in the intervening years, have now narrowed your search to one specific Spitfire/Seafire model and because Seafire development tended to follow Spitfire development  perhaps you could share what you already know about this matter in relation to either type. That way 

 

a. Members here can help you by focussing on the gaps in your knowledge without wandering off to consider other Marks, especially given Seahawks last para, and

b. We might all learn something new.

 

Most of us are on here to learn something new about our hobby and its subjects. We can only do that by pooling our knowledge base.

 

Seahawk,

no offence meant by the way. I too was beginning to turn to consider the Mark XVI and others in production around that time, albeit in different factories from the Seafires.

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I'm on the road, so can't get to my files, but one comment based on a skim of this topic: (so don't jump me if I say things that others have already brought up!)

 

Don't confuse the "short fairing" of the 'e' winged Spits, such as the XVI, with the shorter barrel of the Mk.V Hispano.  I do think that the Mk.V got used on Seafires, but I don't remember actually "knowing anything" about that. 

 

I speculate that the occasional comment that the single cannon (per wing) on the Seafire III was installed in the outer bay (usually "necessary because of the wing fold, which interfered with the inner bay") is in fact a mis-interpretation of a cannon fairing that looks rather like (and could even possibly be the same parts as) the 'e' wing cannon.  I have seen Supermarine drawings that, as I recall, show an actual "e wing arrangement" on the Seafire 17, but I have not yet had any reason to think that they actually ever did that on an airframe.

 

I look forward to coming back to this when I have time to read carefully, and consult my files!

 

bob

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1 hour ago, gingerbob said:

I'm on the road, so can't get to my files, but one comment based on a skim of this topic: (so don't jump me if I say things that others have already brought up!)

 

Don't confuse the "short fairing" of the 'e' winged Spits, such as the XVI, with the shorter barrel of the Mk.V Hispano.  I do think that the Mk.V got used on Seafires, but I don't remember actually "knowing anything" about that. 

 

I speculate that the occasional comment that the single cannon (per wing) on the Seafire III was installed in the outer bay (usually "necessary because of the wing fold, which interfered with the inner bay") is in fact a mis-interpretation of a cannon fairing that looks rather like (and could even possibly be the same parts as) the 'e' wing cannon.  I have seen Supermarine drawings that, as I recall, show an actual "e wing arrangement" on the Seafire 17, but I have not yet had any reason to think that they actually ever did that on an airframe.

 

I look forward to coming back to this when I have time to read carefully, and consult my files!

 

bob

When @gingerbob speaks on the subject of Spitfires, even away from his references, I wind my neck in!  But agree with you in not believing that any 2-cannon Seafire (ie up to and including the F.17) had the cannon in the outer bay.

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I'd like to see more about this "short fairing" on the E wing Spitfires.  A shorter inboard fairing requires a shorter barrel or (as on the B wing) the breech mounting further back in the wing.  I rule out, in the complete absence of photos, the barrel sticking out further from a shorter fairing.

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What I meant was that the shorter Mk.V cannon in the Seafire's inner bay might use the same or similar cannon fairing to that of the more rearwardly mounted Mk.II cannon in an 'e' wing's outer bay.

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6 hours ago, gingerbob said:

What I meant was that the shorter Mk.V cannon in the Seafire's inner bay might use the same or similar cannon fairing to that of the more rearwardly mounted Mk.II cannon in an 'e' wing's outer bay.

So my suggestion (post 13) that the shorter cannon fairings on late Spitfire XVIs might indicate use of Mk.V cannon was just plain wrong.

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OK Bob, but then for the Seafire the inner cannon would also have to be mounted further back.  This seems odd.  Why should they change all details of a perfectly good working system?  Occam's Razor suggests that fitting Mk.V cannon seems a whole lot more likely.

 

Going back to the shorter fairing on the E wing, are we looking at some remnant of the original design for four cannon, where some stagger is necessary for the two feeds?  This also takes the Czech Spitfires out of the story, or do we need extra-short barrels for Mk.Vs in the outer position?  As on later Mk.22s and the Mk.24.   Talking of which, why should the Mk.V be fitted to late production Merlin aircraft yet these later examples still are produced with long barrels?

 

But we also need short barrels for those 4 cannon Malta Mk.VC where the inner gun has been removed.  Fortunately the Airfix Mk.VC gives that.  I wondered what it might be good for.

 

Amazing what scuttles out when you start lifting stones, isn't it?

 

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9 minutes ago, Graham Boak said:

OK Bob, but then for the Seafire the inner cannon would also have to be mounted further back.  This seems odd.  Why should they change all details of a perfectly good working system?  Occam's Razor suggests that fitting Mk.V cannon seems a whole lot more likely.

I don't think the fitting of Mk.V cannon to later Seafire L.IIIs is in dispute.  Both Morgan/Shacklady (p.536)  and David Brown (p.23) say it happened and the existence of photos showing early aircraft with long fairings and later/refurbished aircraft with short fairings bears it out.  It's my apparently erroneous suggestion that the shorter fairings on late Spitfires also indicated Mk.V cannon which has muddied the waters.

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Graham

i think we are indeed looking at the effects of the stagger of the guns to allow for the feeds to lie one behind the other in the wing. Check out the plans of the C and E wings below. Seems to me that in the E wing the cannon sits further back leading to less of the barrel protruding from the wing = shorter fairing required. Hadn’t thought of that before.

 

C wing ( scroll down page) http://spitfiresite.com/2010/04/concise-guide-to-spitfire-wing-types.html/2

 

E wing http://spitfiresite.com/2010/04/concise-guide-to-spitfire-wing-types.html/2

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Which leaves the question of why fit the new cannon to Seafires but not to RAF aircraft.  To be fair, the Seafire could do with any weight reduction.

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I've been deep diving Morgan/Shacklady with a magnifying glass (literally!) to look at the detailed weight tables for the various Seafire models. Unfortunately they don't appear for all models but they are there for the Mark III and the XVII with different tables for the fighter and FR variants. They have a line "2 Hispano guns and accessories" with the weights as follows:-

 

F & FR XVII 221lbs

F/LF III 274.5lbs

FRIII 230lbs with the model of gun specifially noted as the MkV

 

We know the Mk V was lighter than the MkII gun. So this raises another possibility. MkV guns fitted to the FR aircraft only, perhaps as weight compensation which, as correctly suggested by Graham was much needed anyway, but more likely to compensate for the added camera weight in the rear fuselage.

 

Brown notes that Cunliffe Owen built 129 of these FR aircraft from late 1944 with Westland also converting a few. I have a note in my research material that FR production at Cunliffe Owen started in Nov 1944 with NN558. Unfortunately I didn't note the source of that particular piece of info and it may have been conjecture on my part given what follows. Between Nov 1944 and July 1945 they built 172 Seafires from NN558 onwards of which my notes say 50 PX serials were LFIII (per Morgan/Shacklady) leaving 122 v the 129 in Brown. Those are 72 NN serial and and 50 SP serial. Only some of the NN batch found their way overseas with about 16 seeing service with front line units in the Far East. But Air Britain only identifies one as an FRIII:- NN621/ 115-N on Implacable delivered in Feb 1945. This was the aircraft of 880 Co Lt Cdr Mike Crosley in 1945 on Implacable. There is a photo of it in "Eyes for the Phoenix" p161and "They gave me a Seafire" while ashore in Tasmania. It is very difficult to make out, but it seems to me that the starboard side cannon fairing is missing. I'd be lying if I said with any conviction whether it was long or short. All my sources agree however that it was an FR.III.

 

NN610 and 611 were in this batch and were tested against Japanese aircraft at Clark Field in 1945. One was photographed but seems to have the long cannon and has featured on Britmodeller in the past. But was it an FR.III?

Morgan / Shacklady also has 8 Westland built RX serialled aircraft as FR.III most of which went to the French in 1946.

 

As for Graham's last question about RAF Spitfires, it seems even odder that the Mk II cannon seems to have been fitted well into the Mk.21/22/24 series judging by the length of the cannon fairings although Morgan / Shacklady notes later Mk 24s got the MkV gun.

Edited by EwenS

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Hi Everyone,

 

I am really enjoying reading the comments and responses to my question about the use of the Mk V cannon on the Seafire lll.  My apologies for taking so long to jump back in.  I have had a busy weekend.  In response to Ewen's question regarding my research, I have found that the Mk V cannon was not used on any operational Spitfires during WWII.  The Mk V cannon was only installed on some of the late model Mk 24 Spitfires.

 

The Mk ll Hispano cannon was the standard 20mm cannon used on all Spitfires and a large number of Seafires.  With the introduction of the Seafire lll, and the ongoing desire to reduce weight, the Mk V cannon began appearing on later models of this variant.  Compared to the Mk ll Hispano, the Mk V had a higher rate of fire (750 rpm vs 650 rpm), was 12 inches shorter and weighed 25 pounds less.

 

I have seen some videos of Seafire lll's in action that seem to show the Mk V cannon fitted.  I have some screen shots that I will post shortly that certainly appear to show Seafires with the shorter cannon barrels.  However, based on the angle of the picture or video, it is sometimes difficult to tell.

 

Regarding the use of the Mk ll cannon on the Spitfire, the introduction of the E wing resulted in a .50 browning being fitted in the inboard gun bay (where the Hispano had previously been located) and the cannon was moved to the outboard cannon bay.  This resulted in the cannon being moved approximately  six inches further back and a correspondingly shorter cannon fairing.  I had initially thought that maybe the Mk V cannon had also been fitted to the E wing, but I have found no information to support this.  The Mk V cannon did not appear on the Spitfire until the Mk 24 Spitfire variant was produced.

 

I have some pictures showing the long and short cannon fairings fitted to Seafire lll's and will post them in the next day or so.

 

One other significant bit of misinformation I have come across during this search is the reference in many books (including Morgan/Shacklady) to Martin Baker making belt feed mechanisms to replace the 60 round ammunition drum for the Hispano cannon.  The successful belt feed mechanism for the Hispano was based on the French Chatellerault design, and once production on this feed system was underway, the Hispano cannon became an outstanding weapon.  Most of the belt feed mechanisms were built by the Molins Machine Company.  Martin Baker never produced any belt feed mechanisms that were used during the war.  

 

I will post some pictures in days ahead.  

 

roncl

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