Tony Williams

This presumably accounts for the fact that Crowood are also selling Autocannon as an e-book (first time they've done that, as far as I know).

It's now on sale!

Now that I've never seen or heard of. It would need a technical expert from somewhere like the National Firearms Centre in Leeds to sort out!

Greetings all, I've been away for a few years doing other things but have at last completed work on a new book which may be of interest to some here: Autocannon: a History of Automatic Cannon and their Ammunition It covers similar ground to my first book, Rapid Fire, but in much more detail. Publishing date uncertain, but early next year.

I winced when I read that. A mounting which will absorb the recoil of such a powerful gun will be very heavy even when it is basically fixed in place with very limited traverse (as the 105mm is). Putting it in a fixed turret would add considerably to the mounting weight. Making such a turret extendable.....

I think around 4,000-5,000 SIGs were acquired. There was some reason why they abandoned that in favour of a bulk buy of Glocks, but I'm not sure whether there was a problem with the SIGs or whether they just found that the Glocks were better. The reasons given for choosing the Glock were its easy handling, light weight. and speed of getting into action. At the same time, they also said they were building in far more training in its use and were insisting on it being worn in a quick-access holster instead stuffed in a bag or whatever. They didn't want to say so, but it was clear that it was the green-on-blue incidents in Afghanistan which prompted the sudden interest in pistols. They are intended for use on the base when most troops won't be carrying rifles, rather than out in the field.

Interesting indeed - I hadn't read that before. However, my main point about the 5.7 was that if the enemy is wearing body armour impervious to any pistol ammo (5.7 included), then a head shot may be the only feasible option. In which case, traditional measures of stopping power (emphasising bullet size and energy) may be less important than a light-recoiling, flat-shooting gun with a large ammo capacity.

Follow that to its logical conclusion and there's a case for issuing the 5.7mm FN pistol: light recoil means a higher rate of accurate fire for the average shooter, there's 20 rounds in the magazine, and the trajectory is flat. As a bonus, it is also better at penetrating body armour.

Ah, the Studebaker Avanti - one of my favourite cars when I was a kid - I though it looked great!

The Air Force thinks it has a 105mm anyway: http://www.af.mil/AboutUs/FactSheets/Display/tabid/224/Article/467756/ac-130j-ghostrider.aspx The 30mm isn't a gatling, though - it's a single-barrel Chain Gun, a version of the Bushmaster II.

Tungsten-cored AP ammo such as the M993 and M995 is already in the inventory, and probably capable of penetrating any body armour. It's very expensive, which is why it isn't normally issued, but it certainly could be if top-line body armour was being worn by an enemy. If that isn't enough, the obvious answer would be a tungsten-cored APDS loading like the 7.62mm SLAP, a version of which was adopted by Sweden for sniper rifles. However, you really don't want to use that against unprotected personnel, because it's also very expensive, and the terminal effectiveness is likely to be less than with full-calibre ammo. FN did produce an experimental 5.56mm APDS in the 1980s, but the bullet is really tiny. So with that approach, it really doesn't affect the debate over the optimum cartridge(s) for small arms, as long as whatever is used has effective, fully-developed and qualified APCR/APDS loadings ready and waiting for the time they will be needed. The next step up from that would of course be APFSDS, but that works best from smoothbored guns and also has questionable terminal effectiveness against soft targets. Beyond that, you're probably into large calibre HEAT rounds, legal issues aside...

I have to confess to being a devotee of the Roy Rogers and Lone Ranger TV series in the 1950s. Things were so simple then - the good guys wore white hats and never missed with their shiny revolvers despite never taking aim, the bad guys wore black hats and always missed. Where did we go wrong?

Yep. It became clear in the recent defence cutbacks that you save far more money by deleting a complete type from the arsenal than by deleting the equivalent number of squadrons but keeping all types in service. Which, in an age in which value for money has become a lot more important, argues very strongly in favour of minimising the number of aircraft types - although not necessarily versions. For example; MRP, AEW, intelligence gathering etc might be done by different variants of the same basic plane, with transport and refuelling versions being done by another, and so on.

I can beat that. I still use, on a daily basis, the Casio PB410 personal computer which I bought about 30 years ago. It measures just over 6" x 3" x 0.5". You have to enter a BASIC program (manually, of course) before you can use it, and I have several which I have written myself and regularly use. For example, I have ones which calculate bullet sectional densities (input: calibre and weight) and muzzle energies (input: bullet weight and muzzle velocity). The beauty of this is that I wrote the programs to be reversible (e.g. if I know the muzzle energy and bullet weight, it tells me the velocity, or if I input the muzzle energy and velocity, it tells me the bullet weight). A different program converts length and weight measurements from metric to imperial - using the correct sub-units (so if I put in 1.7 meters, the output is 5 ft 7 ins). It is as quick and convenient to use as a pocket calculator - no boot-up time, just switch on and go - and I am frankly worried that if it ever expires I might never find anything which does its particular jobs as well.

I first realised I was getting old when I walked through a house which was being preserved as a museum to show how people used to live, and I recognised a lot of the stuff in it from my childhood...

Good luck to them - it's the kind of initiative that deserves to enjoy some success.

In 30mm M789 HEDP the liner is carefully shaped to compensate for the rate of spin and still produce a focused jet. I don't know about the 40mm GL rounds but it seems likely. I don't think that such technology was feasible in WW2 - it would have been as anachronistic as using APFSDS.

The AC-130 is SOCOM's baby - a separate organisation and budget.

HEAT design has improved considerably since WW2. In particular, designs such as the 30mm M789 HEDP used by the AH-64 Apache gun have overcome the problems of firing HEAT from a rifled barrel (which originally significantly degraded penetration). So I don't think that a WW2-era HEAT shell in 37mm calibre, fired from a high-velocity rifled gun, would have been much good.

This is a reflection of the arguments currently running about warships. The frigates and destroyers (of European navies, at least) spend virtually all of their time on duties which could be performed just as well by an OPV with a small fraction of the acquisition and running costs. But the RN is very reluctant to acquire such vessels (despite being desperately short of escorts to meet the demands on them), arguing that it would lead to a reduction in the number of high-end ships needed for hot wars. They claim that it is therefore better to use costly warships for simple tasks, simply to ensure that you have them when you need them. So the same sort of arguments would doubtless go on over acquiring a cheap combat plane like the Scorpion. The USAF is already unhappy about the small number of F-22 bought, and worried about how many F-35 will actually be acquired. They would probably see the Scorpion as a threat to their future acquisition of top-end combat planes.

Which begs a question: what's the difference in cost between a pilot sitting in the plane and one on the ground controlling a UAV, as a percentage of the total acquisition and running cost of the aircraft?

Not a chance: far too sensible, much too cheap for the aerospace industry to make big profits, so no use to any senior people involved in procurement who might be hoping for a lucrative transfer to industry later...

Some more details of the AAI APFSDS ammo, also from Jane's: Designation M464, 1.63 kg penetrator 20.6 mm in diameter with an L/D ratio of 15:1. Aluminium sabot, total projectile weight 2.52 kg. MV 1,433 m/s. Over 18,000 rounds have been made.

Had a look at what Jane's says about the M41's ammo: "The 76 mm gun fires the following types of fixed ammunition: AP-T (M339), Blank (M355A2), Canister (M363), HE (M352), HEAT-T (M496), HVAP-DS-T (M331A1/M331A2), HVAP-T (M319), TP-T (M340/M340A1) and WP Smoke (M361/M361A1). In 1982, it was revealed that AAI Corporation had developed a new 76 mm APFSDS-T round for the M32 cannon. This was developed as a private venture for the export market and has been sold to Denmark and Taiwan." And about Taiwan's M41D: "It is understood that Taiwan has a fleet of about 675 M41 light tanks which is also referred to as the Type 64. This is similar to the M41A2/M41A3 with a number of enhancements including additional armour protection and a new fire-control system. Some of these have been upgraded to the M41D standard that includes installation of a Detroit Diesel 8V-71T developing 405 hp which increases the operational range. The gun has been modified to fire APFSDS ammunition and is now fitted with a muzzle brake. The M41D also has side skirts and banks of electrically operated smoke grenade launchers either side of the turret and can also lay a smoke screen by injecting diesel fuel into the exhaust." Some M41s are still in use in Thailand and Brazil (refitted with a 90mm gun), but numbers are falling as they are being replaced.

M41D. 76mm, different gun. Thanks - does it still use the same ammo?