Saturday, September 03, 2011


House firearms expert Representative Carolyn McCarthy (D-NY) testifies before congress as to which object is a barrel shroud (she gets it wrong). Don't even bring up the subject of ballistics to these type of creatures.

Sorry, but I can't begin a firearms article without ridiculing how ignorant/stupid those "in power" are on the subject. Politicians, the media, and Hollyweird know considerably less about firearms than I know about, say, performing brain surgery left-handed behind my back while inventing faster-than-light interstellar space travel. But they are not folks who let their total ignorance and outright stupidity get in the way of posturing and blustering like they actually know something about firearms. The political whores in Washington D.C., acting upon the Mel Brooks political maxim of, “Gentlemen, we must do something to protect our phony baloney jobs immediately! Immediately! Immediately!” pass legislation on things they know absolutely nothing about so that they can appear to be “doing something” about a problem, real or imagined. For instance, good old Carolyn McCarthy, Democrat from New York, helped write the gun control legislation which outlawed "assault" weapons with barrel shrouds, even though she had no clue as to what a barrel shroud actually is.

The media always wet themselves over a good crisis and if there isn’t an earthquake, flood, or fire handy they often times make up their own "crisis". For instance, when the 12-gauge Dragon’s Breath shotgun pyrotechnic round came out, Iowa “journalists” had a hissy bitch fit about how dangerous these things were because they looked scary when fired; I am not aware of any crime ever having been committed with a pyro shell. So the press ran around screaming about how these shotgun shells were a deadly menace to everyone and everything until they had created such a stir amongst the non-gun public that the state legislature banned the ammo.

And, with a few rare exceptions such as Clint Eastwood, Tom Selleck or John Milius, Hollyweird, home of the 40-shot revolver and magazines that have an apparently unlimited capacity, has always been ridiculously ignorant of firearms and what they can do. My favorite is their following the media’s hype about “Teflon-coated cop-killer” bullets which, in Hollywood, allows a single 9mm pistol projectile to blow body armor apart like a hit from a 105-mm howitzer and shoot through the dozer blade on a D-9 Cat.

One of the big misconceptions that has made its way into common parlance thanks to such experts is “point blank” range. The way they use the term one would think that point blank range is so short that the victim gets powder burns and that the front sight hits him in the chin under recoil.

The proper definition of point blank range is the maximum distance to which the shooter can hold his sights directly in the center of his target, whether it be the vitals of a deer or a man-sized silhouette, and hit within this vital zone. The formula generally used involves the bullet trajectory neither rising above nor falling below 5 inches of the line of sight. Think of it as the range at which you could shoot straight down a 10-inch pipe without hitting the top or bottom.

Thus, the maximum point blank range of a rather anemic pistol round such as the .380 APC, firing a 90-grain jacketed hollowpoint at 1,000 feet per second, is actually 120 yards with a zero range of 100 yards. No danger of powder burns there.

Maximum point range blank is important for the high power rifle shooter; it allows one to wring the most performance out of a particular load, the longest distance at which you can hold your sights dead on and have a center-mass hit without having to hold over or otherwise adjust. Thus, military battle sight zero is usually 250 meters, which allows to shooter to hold dead on out to 300 meters. All this, of course, is based on the premise that the shooter knows what the hell he is doing in firing the rifle.

Most non-military shooters, especially the average ordinary sport hunter, zero their rifles at 100 yards and call it good. This wastes most of the modern high power rifle’s potential. Oh, the horror!

Let’s take the .308 Winchester cartridge, actually the military 7.62x51mm NATO, launching a 147-grain full metal jacket bullet at 2,800 feet per second. Zeroing the sights at 100 yards, the bullet starts dropping at that range. At just over 200 yards, the bullet has already dropped out of our 10-inch pipe, the range at which you can hold your sights dead on, and you have to start holding higher. With a 270-yard zero range to take full advantage of maximum point blank, you can hold dead on out to 330 yards, gaining yourself a full 130 yards. The average hunter who buys a 20-round box of factory ammo every year or two has no damn business shooting past 300 yards anyway.

Then there's a critter called ballistic coefficient, which deals with how streamlined and balanced a bullet is. I won't go into this too much as I've probably gotten pretty boring already. Anyway, to show what a difference ballistic coefficient can make the above trajectory was calculated using data from the U.S. Army's Aberdeen Proving Grounds, which lists the M80 ball round's ballistic coefficient as a rather pathetic .200. Every other source, i.e. all the different reloading manuals I consulted, list the BC for that same bullet at roughly twice the Army's number, around .400. Giving the political REMF butt-kissers at Aberdeen the benefit of the doubt, I used the lowest civilian BC I could find, which was .393. You can clearly see that BC makes a rather large difference in trajectory. This is just one of the reasons why snipers use heavier bullets for long range work, such as the Lake City M118 172-grain Match load, whose bullet has a BC of .468. Some of the heavier precision commercial bullets can get up to .600 BC, or even higher.

Trajectory of supposedly the same bullet, M80 ball, with a BC of .200 (blue) vs. a BC of .393 (pink). Yeah, I think Aberdeen's full of shit, too.

Military rifles only having to be close enough for government work, i.e. hitting a target the size of a man’s torso rather than a 10-inch vital zone on a deer, I still lean towards the .393 BC. For instance, my Trilux SUIT scope I like to play with so much has two sight settings, one to cover shots at 100-400 meters and one to cover 400-600 meters. The former is zeroed at 300 meters, the latter at 500. According to Aberdeen’s BC, that would mean a 7.62x51mm ball round would be well over 10 inches high at 200 meters and almost 16 inches low at 400. Using the civilian sources, it would be 7.3 inches high at 200 and only 9.3 inches low at 400. I think the British Army would be smart enough to match the SUIT scope’s ranges pretty close to the real trajectory if they expected soldiers to hit what they were aiming at.

This target was shot at 400 yards (not meters as it should have been) with my "bad" FAL and the Trilux SUIT scope. The bottom group was shot with the cam on the 100-400 meter setting, and the top with on the 400-600 meter setting, aiming center mass. Doesn't look 16 inches low to me, as per Aberdeen's BC.

If I haven’t thrown enough confusing gibberish at you, back in WWII scope technology, even the good German glass, was pretty pathetic compared to today, no graduated reticles or elevation adjustments. Plus, the U.S. Army doesn’t like soldiers to monkey around with things and wanted “soldier-proof” scopes, so essentially all you could do was zero the scope at a certain range and leave it there, then compensate for the trajectory at various ranges, which had to be estimated using the Mk I Eyeball, by aiming high or low at various ranges using only simple crosshairs. It was effective, after a fashion, but a good shooter with keen vision might do better with the range-adjustable rear aperture sight on the M1 Garand. Fortunately, today’s sniper and even sporting scopes adjust for range pretty well, and make the WWII-era scopes seem like you’re looking through a toilet paper cardboard tube.

Trajectory for the M2 Caliber .30 U.S. (.30-06) with a 400 yard zero. I think that's trying to stretch things a bit much and unnecessary with modern scopes.

Military snipers back in the 1940's-50's "stretched" the range of the .30-06 with a 400-yard zero and "hold-over" or "hold-under", which made range estimation even more important.

I can hear people by now yelling, “Get to the *#$%* POINT, Bawb!” OK, this was my long-winded way of saying zero a 145-150-grain .308 load at 270 yards for maximum point blank range.

1 comment:

Anonymous said...

Very well done Bawb, and thankfully you finally did get to your point. :D