Quote:
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