However, this is far from an ideal solution, argues Williams, pointing to the weight and bulk of 7.62x51mm ammunition and the associated weight and recoil of weapons chambered for it. In rifles, this recoil makes training more difficult, slows down aimed semiautomatic fire and makes fully automatic fire all but uncontrollable.
The use of these two calibres in an infantry squad enables it to fight at both close quarters and long range, but in either situation part of the squad will be at a severe disadvantage, says Williams, either because their weapons are too cumbersome or because they lack range. As solutions to the problem, he rejects the adoption of improved 5.56 millimetre rounds because the ones with the best performance, such as the EPR and the Mk 318 Mod 0 SOST might be thought to violate a clause in the Hague Convention that outlaws bullets “with a hard envelope which does not entirely cover the core, or is pierced with incisions.” He also rejects wholesale re-adoption of 7.62mm because of the weight and recoil issues.
An Intermediate Calibre
This, he argues, is an argument for replacing both existing rounds with a new intermediate cartridge with good long-range performance for use in both rifles and machine guns. By long-range performance he means up to 900 m. Significantly, this rules out an otherwise strong candidate in the form of the 6.8x43mm Remington Special Purpose Cartridge (SPC). The 6.8 SPC came out clearly on top of the Joint Service Wound Ballistics – Integrated Product Team (JSWB-IPT) tests carried out in 2006 to determine whether any commercially available 5.56mm bullets or other similar calibres could out perform the M855 at ranges up to 500 m. Beyond 300 m though, the SPC loses out to the smaller, lower velocity 6.5x38mm Grendel whose long, slim and relatively heavy (123 gr) bullet retains its velocity and thus its kinetic energy for much longer. Indeed, the Grendel, developed by Alexander Arms, retains almost as much energy as the 7.62mm M80 at 500 m and has marginally more than the M80 at 1,000 m.
An ideal intermediate round, argues Williams, would be between 6.5mm and 7mm in calibre and would fire a low drag bullet at a medium velocity. Such a bullet would weigh somewhere between 115 and 142 grains and leave the muzzle at somewhere between 2,690 and 2,420 fps respectively with around 1,855 ft/lb of energy. Muzzle energy, weight and recoil would all be midway between those of the 5.56mm and 7.62mm rounds. Its performance at 1,000 metres must be comparable with a 7.62mm M80 and the bullet must penetrate typical intermediate barriers – although he recommends that armour penetration should be left to a specialised design – and then yaw rapidly and reliably on impact with the human body. To make it acceptable to users who have the strictest interpretations of the laws of war, says Williams, a bullet with a full metal jacket must be available.
As possible future candidate rounds, he postulates 6.5, 6.8 and 7mm bullets in conventional cases 45mm long. Advanced rounds of either caseless or case telescoped design should have the same performance, he argues.
Some critics object that the problem lies in soldiers’ training, not the ammunition. Williams responds that training, while vital, cannot compensate for inadequate ammunition.
Some believe that long-range ammunition is wasted in a rifle, to which he responds that sighting systems now under development will overcome that problem.
An intermediate round would certainly weigh more than a 5.56 round and therefore, some argue, would increase the soldier’s burden. A counter to that is that an intermediate round will be lighter than the 7.62 and at that soldiers may not have to carry as many intermediate rounds as they carry 5.56 rounds today to achieve the same or greater effect.
Some point out that there is no such thing as a “golden bullet” that will solve all combat problems, to which Williams responds that the smaller the cartridge, the more likely it is to fail.
Others say that small arms are irrelevant at long range and that soldiers rely on heavy fire support from artillery or aircraft in those circumstances. Williams counters that such fire support may not always be available and may not be appropriate when there is a high risk of collateral damage.
Developing a new round would certainly cost money, but one general-purpose round would halve the required number of weapon types, Williams says.
Some argue that Afghanistan is not typical of conditions that soldiers will face in the future. Williams counters that it might indeed be typical and better ammunition is always useful.
A Case Against Change
Finally, Williams proposes a small-scale research and development project whose aims will be to determine the optimum calibre and ballistics of an intermediate round. The project will also produce conventional options for testing, provide information for advanced ammunition technology programs such LSAT, and provide a backup in case such programs fail.
In what was effectively a counter presentation entitled: The Case Against Calibre Change, William F. “Wilf” Owen argues that the adoption of intermediate calibre would not make the UK infantry platoon more effective, but would involve a large expenditure of money for no benefit.
Since 1921, he says, British infantry have been trained to group 10 centimetres at 100 metres in order to enable them to hit a man-size targeted at 300 metres when shooting from the prone position and not under stress. “Testing has shown that when standing and stressed, consistent hits only occur at less than 30 metres using a Figure 11 target. An intermediate calibre would make no useful difference!” Hits, he argues, are largely dependent on rate and volume of fire.
Wilf Owen asserts that there is no evidence to suggest that the ranges at which light weapons are causing casualties have changed significantly since 1945 or are changing. Nothing beats shot placement and multiple hits, he argues, and asserts the bullets that fragment are generally more effective at tissue damage than marginally larger rounds that do not, and that much depends on the target’s physical attitude, whether they are lying down or standing, for example. He also warns against pseudoscience in the areas of ballistics and lethality, saying that there is complete lack of forensic data (on what is killing and wounding the enemy in Afghanistan), and against relying on anecdotal reports from soldiers who say they hit their target but the bullet didn’t work – “they probably didn’t.”
He observes that automatic fire is the most likely to gain hits on moving all short exposure targets at any range, and that projected high explosive is extremely effective when used. Further, he notes the optical sight aids accuracy and speed of target acquisition disproportionately, and argues that when funds are very limited, as they are now, it would be better to spend the money on sighting systems than new calibre of ammunition.
New Zealand’s Small Arms Needs
Ammunition effectiveness is also an issue for the New Zealand Defence Force (NZDF), which, according to Army Lt Col Mike Beale, needs a light support weapon that’s destructive out to 800 metres. “We need to go to 7.62 because 5.56 just doesn’t cut it.”
The light support weapon is slated for replacement in an infantry weapon renewal programme that was announced in 2007 and is due to complete in 2014. The gun in question is the 5.56mm C9 version of FN’s Minimi. The New Zealand Army already operates the 7.62mm FN MAG 58 alongside the British L7A2 variant of the same weapon, but is likely to choose something lighter than the 11.79 kg MAG for the LSW role.