ID guns on these MCC trucks

[Mike Cecil]

Yes, Mike: I've just read through it, and its a good coverage of the gun and ammunition. Not much reference to Australia (esp WW2 use in the ME and Pacific) but that's a minor point in the overall scheme of things.

The explosive action of the Shrap shell 'ejects' the balls/shot from the casing, which then falls to earth, often remaining intact. Many were subsequently souvenired, and thus it is probably the most commonly available variant of the 18pdr in collections because of that.

Mike C

[David Hardway]

Hmmmmmm i know these pics of the approx 10 Morris CDSW tractors to come to NZ there are remains of at least 5 still known to exist just not really enough to build a decent truck

Dave

[David Hardway]

Heres some more from the same sequence note the threadbare tyres on the limber

Dave

[Lang]

MikeC,

Good info as usual.

I think your info on reducing the range with elevation is suspect - you can't beat physics - 45deg is maximum range for any projectile, thrown rock, motorcycle jumping busses or garden hose. Shot-put and javelin athletes aim for an exact 45deg launch.

I seem to remember "howitzer" referred to a weapon capable of higher angles than 45deg - very useful for high crest clearance or tossing over a hill ie the shells go further and further as the gun gets to 45deg then start coming back in - try it with a garden hose. In theory, if you can get it high enough (mortars have no trouble) you can drop a shell down almost vertical behind a building 100 metres away - or maybe back down your own barrel!.

They had a reasonable range because they had quite a good muzzle velocity. For those whose memory needs jogging like mine these days, the weight of the projectile has absolutely nothing to do with its range. If we had a target at 100 metres a 22 aimed direct would hit it about 5 inches low, a heavier 243 would hit it about 1 inch low and an even heavier 18 pounder would hit it about 8 inches low. It is all to do with the time in the air while gravity is pulling them all down at 32 ft/sec/sec so velocity is king.

I can't figure out why they only had 16deg unless they were designed as a direct fire weapon - it would make them almost useless as an indirect fire support weapon. Any ideas? I suppose they came from an era where the commander still stood on a hill and directed the battle visually.

[Lang]

Just done a bit more research on the 18 pounder. The Kiwis were certainly sold a pup if they bought those early guns. Maybe they are an anti-tank unit?????

They were designed as a direct fire weapon and obviously upgraded to indirect fire as better sights were invented during the post Boer War period (quite amusingly the Brits chose a German manufacturer to make their sights). During WW1 they were soon upgraded to 30deg elevation and then 37deg as mentioned above by redesigning the trail..

I think the Kiwi buying committee were misunderstood by the Brits when they ordered guns for 'ndrct' fire.

[Mike Cecil]

That gave me a laugh, Lang!

I agree that velocity is 'king', and I don't think I was specific in mentioning the angle at which the fall of shot starts moving back: but I believe what I said was correct as stated.

Now take the 18pdr's successor, the 25-pdr, described as a 'gun-howitzer'. Although its max angle of elevation on carriages Mk.1 and 2 (and sub variants) was less than 45 degrees (actually a max of 40 degrees with spade embedded), the fall of shot could be varied by another factor: varying the charge weight (it was a semi-fixed cartridge), hence, varying the velocity. The combination of those two factors gave the weapon much greater flexibility: everything from 'lobbing' shells over tall hills at low velocity (indirect fire) to firing anti-tank shot direct on Charge Super (at max velocity). The Mk.3 carriage gave even greater ability to clear crests, being articulated to give an even greater max elevation well over 45 degrees.

Mike C

[RHClarke]

Gunners have never been constrained in the use of their field pieces by engineering/manufacturing specifications. Fixed max elevation on 18 Pounders and 25 pounders were overcame by digging in the trails (http://books.google.ca/books?id=oLge...g%20in&f=false see image at page 38). This changed the maximum ordinance or max height of a round and its overall range. The data for exceeding max elevation could not be found in its firing tables, but the fall of shot would be consistant making adjustment of artillery fire at high angle a reality.

Modern day howitzers (towed or tracked) have a greater ability to engage targets in "high angle" or in the "upper register" than their predecessors, but if you absolutley had to engage a target close to the gun position but hidden behind a high obstacle, you need only to request fire from another call sign (arty, armoured, attack helicopter or if they check out of the Holiday Inn on time, fast air support) that can reach out and touch the target.