I am writing in response to the excellent article titled "Is 6mm the Optimum Caliber?" by Stanley C. Crist, in your September-December 1999 issue.
Mr. Crist's article makes sense as far as weapon performance goes, but to implement his concept we would have to declare our entire inventory of small arms and ammunition obsolete, replace them at tremendous expense, develop the replacement weapons, pay for an entire inventory of new small arms guns and ammunition, and institute new training. "Our" ammo and weapons have NATO Standardization Agreements (STANAGs) behind them, agreements signed by the United States and other NATO countries.
The changeover to a new caliber (and new weapons) could not be done quickly, if done at all, and for a long period of time we would have three different rounds in use and turmoil in our inventories.
Such a decision would affect not only the United States, but NATO nations and others that have bought U.S. guns and ammunition, as well as other countries which have bought weapons that use the current 7.62mm and 5.56mm ammo. Many of the NATO nations would argue that we forced the 5.56mm ammo on them, as we did the 7.62mm ammo, and now want to force a 6mm round on them.
Neither the money nor the will is there. Mr. Crist is a gifted and creative person whose articles have been excellent. This article is excellent, too, but I believe that a 6mm cartridge is a nonstarter.
The 6mm cartridge may indeed be a "nonstarter," but not for most of the reasons Mr. Loughlin cites. As I see it, two factors are serious obstacles to the implementation of the 6mm concept in the near future: First, although they are not the best possible calibers, 5.56mm and 7.62mm weapons do deliver usable performance, so it may not be cost effective to replace them while they are still serviceable; and, second, the objective individual combat weapon (OICW),--if its very challenging design goals can be achieved--will render rifles of any caliber obsolete.
The adoption of a 6mm cartridge is probably dependent upon the reemergence of a desire for a common caliber for rifles and machineguns. This change in attitude has happened before and could happen again, especially if the OICW does not enter service.
The expense of a changeover ought to be manageable and affordable, because 6mm weapons would cost a fraction of the price of the OICW. If the OICW is not acquired, more than enough money should be available to buy 6mm rifles and machineguns.
It is true that for a time there would be three calibers in the system. This is hardly an insurmountable problem, however, since the Army accomplished just such a task during the changeover from .30-06 and .30-caliber Carbine to 7.62 NATO.
While NATO STANAGs might impede the adoption of 6mm, they would not necessarily prevent it. The 5.56mm became the Army's primary rifle caliber at a time when it was not NATO standard, so a third rifle caliber could probably also be pushed through, if the leaders considered its advantages worth the effort. This could conceivably come about because of the increased emphasis on urban combat in recent years.
Like the 5.45mm Russian round, 5.56mm NATO Ball has little ability to defeat many barriers (such as bricks, concrete blocks, lumber, automobiles, etc.) that are common to the urban battleground. After their experience in Chechnya, the Russians are reportedly so dissatisfied with the performance of the 5.45x39mm that there is a move back to the older 7.62x39mm. If the U.S. Army is serious about preparing for the urban fight, is it wise to continue arming U.S. infantrymen with a rifle and light machinegun that can't punch holes through the enemy's cover?
To be sure, the adoption of the 6mm Optimum would be much easier if the United States were not part of a huge alliance. This is why I wrote that the Army missed a "golden opportunity" in the post-World War II years--the one time when 6mm could easily have been made the NATO standard. Since it would have been more in accord with British and Belgian desires for an intermediate cartridge, 6mm would probably have been accepted without the acrimony that accompanied the adoption of the 7.62x5 1.
Incidentally, there was one other period when the Army missed a chance to adopt a 6mm round. A hundred years ago, the Army and Navy decided to standardize their small arms. For a number of seemingly good reasons, the .30-caliber Army cartridge (which was obsolete even before 1899) became the standard, even though the 6mm Navy round was a more modem, technologically advanced design. If the 6mm Navy cartridge had been selected, and properly developed, U.S. armed forces would have had a nearly ideal rifle and machinegun caliber for the past century.
STANLEY C. GRIST