ID guns on these MCC trucks

[Local Chap]

Originally Posted by Mike Cecil

Lang,

To clarify, I didn't say that the 'higher angle/less range' could happen at less than 45 degrees. I simply stated that, for a fixed cartridge like the 18pdr, there comes a POINT where further increases in elevation cause a decrease in range. You later specified this to be 45 degrees, with which, all things being equal, I agree.

Mike C

The range of a artillery projectile is primarily dependant on the Muzzle Velocity, rather than the ammunition type being fixed or semi-fixed. The 4.7in AA gun (aka 28pdr) has a greater range than the 25pdr, and uses fixed ammunition. There are at least 2 recorded instances in the Aust Army during WW2 where 4.7in guns were used as field guns at a range beyond the 25pdr's (Milne Bay and Morotai). It did involve some co-operation between the crews, with Fd Gunners setting the fuzes and the AA Gunners calculating ranges and time of flight. The point that Mike has made is that the Semi-Fixed type offers far greater flexibility in controlling MV.

All guns have range tables that show range for elevation. For fixed types, this is a simple chart that shows elevation x = range y (with other variable calculations for bore wear, temperature, altitudes and in some cases windspeed!). For the 25pdr and 105mm (both of which use semi-fixed ammuntion), there is a separate range table for each charge (25pdr has Charge 1, C2, C3 and Super Charge, while 105mm has C1, C2, C3, C4, C5, C6, C7 and Super), and again each one is affected by variables. The 25pdr has effective range from 100yds on Charge One at zero deg to 13,900yds at 45 deg on Super for a gun in peak condition on a cool day at low altitude. For a gun with a worn bore, on a hot day at high altitude (all factors which affect MV), the max range drops to 12.300yds!

Interestingly, the table for 4.7in AA gives a maximum range of 20,600yds at 46 deg

[Lang]

MikeC,

I was not trying to enter a dispute with you Mike just read your first info regarding 18 pounders only going to 16 deg then mentioning they actually reduced range at higher angles because of fixed ammunition. I presumed you were suggesting much over the 16deg was the limit - I apologise for reading you wrong.

We now have established that 45deg is maximum range for any projectile whether fixed cartridge, variable cartridge or hand thrown and in fixed conditions velocity out of the barrel is all that counts for each individual shot. I suppose that is why when doing a concentrated shoot 4 identical guns, sitting within yards of each other with identical sight settings and shells flying through the same winds etc all have to have individual corrections to get everybody hitting the same spot.

You can hear the difference when you get the order "FIRE" and everyone goes within a micro-second of each other in one big explosion but half a minute later you hear in the distance Bang, Bang Bang Bang as the faster muzzle velocity shells sprint ahead of the rest.

As the members say above, once the gun variables are dealt with (temperature, wear, charge etc) and a muzzle velocity is established you start dealing with winds etc. Amazingly accurate over such huge distances but the calculations only get you in the ball park and we still are really firing Napoleonic cannon balls and correcting from what the FO sees by eye. We will never get first shot accuracy every time until we have field guns doing a Tomahawk Missile using GPS coordinates inside a "flying" shell itself.

[RHClarke]

Originally Posted by Lang

MikeC,.... We will never get first shot accuracy every time until we have field guns doing a Tomahawk Missile using GPS coordinates inside a "flying" shell itself.

http://www.defenseindustrydaily.com/...of-target-032/

"within 10 feet of target" - not bad considering the kill radius is over 30 meters.

[Marc van Aalderen]

Hi,

Here are some pics of the original WW1 18 Pdr. before conversion to modern rubber shoes. These were taken at Firepower, the Royal Artillery Museum in Woolwich Arsenal, UK. I find the projectiles very large compared with the cases. One would imagine the range to be limited because of that.

P7140125.jpgP7140126.jpgP7140127.jpgP7140130.jpg

Cheers,

[Lang]

The article says they will roll out in 2006 - did it happen? If so they must be saving a bunch of ammunition in Afghanistan. Very effective as the bad guys don't have time to hide while the guns stab around the countryside like a blind man with a cane (the FO) before they get "on".

There is one drawback to all this progress - in a full-on war the other team have the same technology.

[RHClarke]

Originally Posted by Lang

...There is one drawback to all this progress - in a full-on war the other team have the same technology.

Yes, but our ammo won't be made in china.

[Mike Cecil]

Ooops.... just noticed a blunder in my previous post, when I stated:

: "varying the charge weight (it was a semi-fixed cartridge)".

Wrong: the 25 pdr is a Seperate cartridge, not semi-fixed. 105mm Howitzer is semi-fixed.

Sorry guys... I should know better!

Mike C

[Alex Blair (RIP)]

Originally Posted by Mike Cecil

Ooops.... just noticed a blunder in my previous post, when I stated:

: "varying the charge weight (it was a semi-fixed cartridge)".

Wrong: the 25 pdr is a Seperate cartridge, not semi-fixed. 105mm Howitzer is semi-fixed.

Sorry guys... I should know better!

Mike C

Mike..
You see that we were very tolerant of your "blunder"..and took advancing age into consideration...
(Keefy made me do it...!!LOL)

[Lang]

Originally Posted by RHClarke

Yes, but our ammo won't be made in china.

I would not be too sure about that. A good Chinese company would not let something like a war interfere with business. If we make them ourselves we will only be able to afford half as much "better" ammunition because the factory workers will be on rostered days off, maternity leave, accrued holidays, stress leave, public holidays, compo for bad backs etc etc etc

[RHClarke]

Originally Posted by Lang

I would not be too sure about that. A good Chinese company would not let something like a war interfere with business. If we make them ourselves we will only be able to afford half as much "better" ammunition because the factory workers will be on rostered days off, maternity leave, accrued holidays, stress leave, public holidays, compo for bad backs etc etc etc

If you are not worried about quality and precision, then buy from China.