Military round comparisons

[Trooper]

While these discussions are entertaining I am yet to see anything that looks like a weapon system specification. Before one can even discuss the cartridge one must define the mission. What range, what target, what protection level, what dispersion. Decisions on projectile energy must be underwritten by the required level damage within a known and defined target, thus one can shift mass, caliber and velocity as variables but only in consideration of the recoil level imposed by the weapon weight. This now in turn drives the projectile construction which then in turn provides the envelope for the casing. The engineering decision then becomes a balance of the operating system type, pressure and weapon weight, and then finally drops to barrel length.

But it all starts with hit probability and range, followed by an accurately defined and scientifically backed target description.

In consideration of the Wolf projectile for the steel case, this was a balance for a economical construction of projectile with good external ballistics for shorter barrels. The primary goal was economy everything else was secondary. Given the space envelope a lead free 110 grain projectile with a Bc value approaching 0.480 is quite feasible. The lead free construction can be used to advantage when considering protected target types typical of the modern battlefield. What is less inviting for the Grendel is the PPI for a mid life upgrade unless powder technology for insensitive propellant advances in the same timeframe.

Three weapons: the PDW of the common soldier as currently manifested in the M4, a DMR (markmans rifle) with 20" barrel and a light MG like our SAW (M249). Currenly both the US and the UK infantry squad have an PDW (M4 or the Enfield for the UK) in 5.56x45, a SAW in 5.56x45, a DMR in 7.62x51 and a medium MG in 7.62x51. That is four weapons with spare parts and two seperate magazines, two MGs with seperate belts. Thus the desire to have a General Purpose Rifle that could be the PDW (16.5" barrel) or the DMR (20" barrel). Afghanistan has put targets out at 500 meters, too far to be effective with the 5.56x45. Thus the need for the DMR and med MG in 7.62x51. Plus both Iraq and Afghanistan have buildings made of brick and stone which tend to not be effected by the lighter 5.56x45.

I am putting together a piece, which I will post here, on the GPC/GPR.