There are few topics as thoroughly penetrated by voodoo, snake oil, and outright cons as is that of firearms marksmanship. The last decade and a half in particular have brought about a truly monumental surge of claims, myths, and collective wisdom as various egos and financial interests look to chisel off a piece of the action.
In the world of guns, the word "tactical" in an item's name or description is often a key indicator that what you're looking at is more marketing than substance. In the same usage, though much older, is the phrase "match grade", or just the word "match". Both "tactical" and "match" used to have very specific meanings, which, over time, have been diluted into basically worthless buzzwords.
To understand the origins and original meaning of "match grade", we need to start with a small history lesson.
Match grade ammunition is not a new concept. In fact, the original match grade ammunition comes from the early days of the National Match, an originally military-only shooting competition that to this day permits only military issue rifles, almost exclusively in their original configurations. Some examples are the M1903 Springfield or the M1 Garand, though as of late, AR pattern rifles in military configurations (minus select fire) are also allowed.
Since the competitors were originally very limited on what they could do to improve their guns, they focused on their skills (the purpose of holding the National Matches to begin with) and their ammo. Since the rules specified military issue ammo only, when it became clear that the issued ammunition was the bottleneck and not the skill of America's best riflemen, a special type of ammunition was manufactured and issued specifically to competitors. It was called "match grade", as opposed to service grade.
Match Grade ammo was originally made to the same overall specifications as service grade ammo, but with much, much tighter tolerances. In other words, it used the same components, but each round was much closer to identical to the others than with service grade ammunition. Later iterations saw departures from the exact recipe, but the idea was still the same: Highly consistent ammunition issued on an equal basis to every competitor, in order to eliminate as many non-skill variables as possible in the competition.
This was to be sure an exploitation of a loophole, but it was exploited officially. In fact, early Match ammo is itself a collector's item. Even just the original packages command a premium depending on year and condition.
The full history of the National Match is well beyond the scope of this article, but suffice it to say that it has been responsible for some of the largest leaps in the art and science of modern marksmanship, partly due to the conniving of the shooters and later, shooting teams, to eke out the most performance possible from within the confines of the official rules.
For example, not content with the consistency of even the National Match ammo, some decades ago some crafty shooters started pulling it apart and putting it back together with the same components but to even more exacting standards, tailored to precisely fit their individual rifles. For those not familiar, modern ammunition consists of a case (usually brass in the US and Europe), a primer (the primary ignition source), powder, and a bullet (the actual projectile is properly called the bullet, whereas the whole assembly is a cartridge or round). Some even went so far as to count individual pellets of gunpowder with tweezers and magnifying glasses, and sort the bullets themselves by .0001 of an inch in diameter and .01 grain by weight.
Much later, amateurs and professionals alike would buy cheap, surplus service grade ammunition that was once available in massive quantities as the US sold off the huge wartime stockpiles. It was ideal for use in experimenting, chiefly since it was so cheap, but also because the specifications were well documented and the powder was of a well-known type. Many shot it as it was, but that's not as interesting as what some people did with it: tear it apart and mess with the recipe. Some did little more than replace the relatively inconsistent and old fashioned projectiles with much more advanced, commercially available projectiles. Some would go an extra step and replace the powder or modify the charge. In any case, the end result became known as "Mexican Match" ammo. The origins of the name are lost to history, but aside from the obvious possibility that it was intended to be derogatory in the same way as the term "nigger rigged", some speculate that it was due to its early use in the first widely recognized amateur-only matches which were held in the Southwestern US, including some across the border on privately owned ranches.
Regardless, the term is no longer in wide use, nor is the practice widespread. Advances in technology have made modern service grade ammunition more than good enough for all but the best shooters, and it's not nearly as cheap in bulk as it was in the 50s, 60s, and 70s. This, combined with the easy availability of extremely high quality ammunition right off the shelf from a variety of manufacturers has lead to a drastic decline in the art of precision hand loading.
There is, however, a renaissance underway in the fertile grounds of foreign surplus ammunition. Although Greek surplus .30-06 has been a topic of discussion for years in certain circles, it's starting to dry up, as are most other NATO caliber surplus stocks. What I have been focusing on lately is the cheap, nasty, and readily available surplus 7.62x54r and 7.62x39 coming out of Russia, China, Bulgaria, Romania, and a few other countries.
The currently available surplus 54r is actually not really all that bad. Considering that it's not even meant for rifles, but is instead loaded to standards of consistency intended for use in machine guns, it typically does pretty well. A decent shooter with a decent surplus rifle (for example, a venerable Mosin Nagant that hasn't been completely trashed over the decades), and some 1970s production or later ammo, can usually shoot about 3-6 MOA. In other words, with all of the bullets hitting inside a 3-6 inch circle at 100 yards. MOA, or Minute of Angle, describes a cone projected from the muzzle of the rifle. 1 MOA is almost exactly 1 inch at 100 yards, or 2 inches at 200 yards, and so on. Although as DonJaime reminds me, the proper mathematical term is Minute of Arc; but the "shooter's MOA" is sometimes set to exactly 1" at 100 yards for the purposes of finely calibrated optics, although the very small difference is usually ignored.
The size and variation of these groups with surplus ammunition is almost always due to what are called "fliers" - rounds that "fly" outside of the group, usually due to a shooter error like flinching, poor trigger or breath control, or inconsistent sight picture. Experienced shooters can usually "call their fliers", or recognize a bad shot right after they take it. There are very few things that are more frustrating than getting four rounds within an inch of each other and then having one go for a walk, especially when you're confident that it wasn't your fault.
Key to accurate marksmanship is consistency - something that has been mentioned several times so far without an adequate explanation. Essentially, an accurate rifle is one that will take the same inputs and deliver the same outputs. In other words, if the shooter does the same exact thing over and over, using identical ammunition, the rifle will put the bullets in the same exact place every time. Even tiny differences in the dimensions of the loaded round, the charge weight, the bullet diameter, the bullet weight, the temperature of the barrel, the position of the shooter's hands and arms, and even the force with which they pull the trigger can affect the flight of the bullet.
At the very top end of equipment and skill, it's not unheard of to be able to hit a 20" steel gong 10 times in a row from a mile away.
But we're not talking about the very top end of equipment and skill. We're talking about cheap surplus rifles and cheap surplus ammo.
A few years ago, when I started shooting large amounts of 7.62x54r in particular, I suspected that many of the fliers, and much of the group size, with surplus 54r was due to sloppy manufacturing. My suspicions were confirmed when I tore down a sample of 50 rounds from a single lot and found a range of .025" in overall length (OAL) and 5 grains of powder. The standard for decent modern commercial loads is about .1 grains variation, and about .005" on OAL.
As an experiment, I used the same cases, bullets, and powder to reload 50 rounds to an OAL of +/- .001", and +/- .1 grain of powder, and found that group size decreased by about 2/3, with fliers caused by ammo all but eliminated.
Although the ammo was Bulgarian, it was originally made to a Russian specification and meant for a Russian rifle - thus the term "Moscow Match". For the cost of a little extra time, the results are impressive improvements in performance.
One important distinction with Moscow Match is that the cases are generally made of steel, which means that they are not safely re-usable, unlike brass cases which can be used over and over again. This is part of the reason why steel-cased ammo is so cheap. It doesn't really matter though, since buying it is almost always cheaper than buying the powder, primer, and bullets separately, and then putting them into reusable brass cases. It also takes about the same amount of work. In fact, there are times when buying ruined surplus ammo (water damaged, usually) just to re-use the projectiles is an economical choice!
Moscow Match is an interesting middle ground in terms of cost vs. benefit, and time vs. utility. If done properly, it produces ammo that is good enough for anything but the demands of ultra high precision matches, and it's probably the cheapest way possible to build a specific load that is tuned to a particular rifle. Since you have control of the exact powder charge, overall length, and can even sort the projectiles and cases into closely matched batches, if you're willing to put in the time, you can come up with some remarkably efficient and accurate loads.
The downside, of course, is that you need to start from scratch and re-develop a load every time you buy a new case of ammo. Unlike reloading using commercial components with fixed recipes, the powder in surplus ammo is different from run to run. I can, for example, recommend a load using 47 grains of IMR-4350 (a popular commercial powder) and my friend can go buy a can of IMR-4350 anywhere in the world and know that his powder is the same as mine. With Moscow Match, though, you must develop a load using the components as they are: unknown.
In my experience, the best way to work it out is to sample a statistically relevant number of rounds from across the whole case, and use a starting load of 90% of the average charge with an OAL of no shorter than the average. From there, you can use standard load development techniques, though I prefer to work the charge down from there first to find the most accurate combination. Never mix powder from batch to batch! It might look the same, but unless you can positively decode the cryptically coded and often times incomplete powder data on the original factory packaging, you can never be sure that it's really the same.
But now let's look at what happens when a good concept fails completely in execution.
The Moscow Match concept is frequently applied in a very ass-backwards fashion. It starts with cheap, steel-cased 7.62x39 surplus ammunition, which is then disassembled solely to reclaim the powder and projectiles. The original steel cases with primers already installed are thrown away, and the powder and bullets are loaded with commercial brass cases and primers.
Despite the typical savings in using reclaimed components, this might be the stupidest possible way to load ammunition. Due to the wide popularity of 7.62x39, even surplus commands fairly high prices as compared to commercial ammunition. It basically doubles the cost of the ammunition, and provides laughably diminished returns in terms of cost vs. accuracy potential. Part of this is due to simple physics: 7.62x39 is not a particularly ideal round for long range marksmanship, and is an intermediate cartridge in the same class as 5.56 NATO/.223 Remington. It is far less powerful, especially at long distances, than full sized rifle rounds like 7.62x54r, 7.62x51/.308 Win, .30-06, or even the comparatively ancient and venerable .30-30. Basically, converting surplus 7.62x39 to Moscow Match, rather than just buying powder and projectiles, is all of the work, extra cost, and little to no benefit.
Some claim that their rifles do not function properly with steel cased ammo; the most frequently cited reason is the lacquer coating fouling the chamber. Others don't care to clean their rifles after shooting them, which can be a problem when using the corrosive primers in most surplus ammo. Both problems can be solved by using a properly chambered and adjusted rifle, and by cleaning it, or at the very least squirting some solvent down the bore before storing the rifle. It is this second concern, the corrosive primers, that causes much confusion among shooters. The term is something of a misnomer, since the primers themselves and their byproducts are not inherently corrosive or damaging to firearms. The byproducts are hygroscopic salts, which if not cleaned can collect moisture from the environment and hold it against the metal, causing rust. They can be simply and easily dissolved with most common gun cleaning solvents, or even plain water.
An endless number of old colloquialisms spring to mind when discussing marksmanship, and the one about poor craftsmen blaming their tools is certainly at the fore. There is something to be said, though, for the tools. While a great shooter will make a mediocre gun sing, said shooter is certainly in a better position to wring out the real benefits from a truly excellent rifle.
These days, though, when $500 buys you a rifle that does MOA or better right out of the box with factory ammo, there are an awful lot of people blaming the wind, the tide, and yes, the Coriolis effect for their inability to hit a paper plate at thirty feet. Meanwhile, military snipers and designated marksmen in Iraq and Afghanistan, when faced with a shortage of the special grade 7.62x51 ammunition meant to be used in their sniper rifles, switched to using the service grade 7.62x51 ammunition meant for machine guns, in most cases pulling it right out of the belts meant to feed the M60s. They found that for practical purposes in combat, it did not significantly hinder their operations.
If you're interested in shooting, I would suggest getting out and doing some actual shooting at the earliest possible opportunity. You may even look to see if there are any rod and gun clubs nearby, though a knowledgeable friend or family member who you trust to be safe is your best bet for a good start.
In any case, don't pay too much attention to the fine points and advanced theory - doing is the best learning, and the rest is just arguing on the Internet.