Monday, April 18, 2005

Loooooong range shooting

In Magnum Opus, I said:
To my mind, if you can't take it with a .270, a .308, or a .30-06, then you can't take it with a 7mm, or any of the .2xx or 6.x magnums.

Welllll...... except some of the semi-wildcats like lazzeronis. He makes a 6.53mm (.257) magnum that puts a 120 grain bullet out to about 4000fps, and that will give you some RANGE. Basically he takes a .375 mag case and necks it down to take a .257 Roberts bullet. Of course it's still only a 120gr bullet so I'd still worry about an Elk or bigger with it; really it's just going to make the longer range shots on medium game safer.

And that's pretty much it right there; honestly, that's the only benefit I can see from the smaller magnums...

...Anything MORE than the 7MM, would really be overkill. You don't need a .300 win mag or a .338 for Elk (unless you want to go out past 600 yards), and there's nothing bigger than an elk that I'm going to be hunting. Really the only reason I'd even consider the 7mag is for the extra 100 yards of safe range it's going to give me on a beast the size of wapiti.
So, like I said, the real reason for the magnums isn't so much to get extra killing power, it's to maiintain reliable killing power at longer ranges.

In comments to that piece reader Gadfly Responded with:
The ballistics on the lapua are almost not to be believed. Have you ever tried one out? I would never try a shot over 300 meters, unless I had an ideal set, but it would be nice to know you had a 1000 meter weapon.
I've fired a McMillan in .338 a few times, and yeah, it's a pretty sweet chambering; of course you feel every ounce of it, even in a 14lb gun.

Oh and the $4000 price tag doesn't help either; but hey, you get what you pay for.

To clarify, I'm talking about the .338 Lapua magnum; a semi-wildcat chambering that was developed specifically for long range tactical shooting (sniping, counter machine gun fire etc...). It's a pretty damned impressive round, neatly brdiging the gap wtween the .300win mag, and the .50 BMG.

The .338 was originally developped by wildcatters in America, but the Finnish company Lapua took a look at it (because the finnish government was looking for a new sniper rifle), and thought it would be an ideal sniper round, and decided to make it a factory offering; making a deal with Accuracy International to supply rilfes in the (now factory supported) chambering.

Their thinking paid off. With factory support behind it, the .338, now named the .338 lapua magnum; rapidly became the long range chambering of choice for tactical shooters, and long range benchresters alike.

Here's an exceprt from "The American Hunter" magazine talking about it's salient properties:
Its performance curve lies much closer to the big .50's. It carries 3,452 ft.-lbs. to 300 meters, compared to 1,438 ft.lbs. for the .308 Win. at the same range. At 1,000 meters the .338 yields 1,308 ft.-lbs., the .308 just 221. The Lapua bullet drops 13 inches at 300 meters, 370 inches at 1000. The .308 bullet strikes 16 and 506 inches low at those respective distances. Snipers needn't compensate as much for wind with the .338 Lapua, either. Its bullet drifts less than half as far as the .308's in a 10-mph wind. While you must tolerate more rifle weight and recoil with the Lapua, this .338 has much less kick than an untethered .50 BMG.
To my mind, there's no such thing as a gun that's reliable much over 1000 meters; my definition of reliable in this instance being a gun that will put 10 rounds into an 8" circle (about .8 MOA).

Sure there are individual god guns that will do 1/4 MOA at 1000m; but as a general rule for the chambering, not even a match .50 is that precise past 1000m. Even McMillan says their match .50's are .5 moa at 1000m, under ideal circumstances, with perfect ammo; and McMillan are the best (AI folks may dispute that, but it's a difference so small as to be unmeasureable).

Most quality .50's not in the McMillan/AI territory, are capable of between 1 and 2 MOA at 1000m; Ronnie Barrett for example quotes under 1moa for some models, under 2moa for others.

Of course the .50 in general is viable well past 1000m; because it's very heavy, aerodynamic bullet retains velocity and stability (and cross current resistance) out to between 1500 and 2000m. The .50 just isn't reliably precise by the standard listed above at those ranges (again, individual god guns notwithstanding).

The .338 however is probably the MOST precise long range chambering out to 1000m; in the right gun it IS reliably that precise (or significantly more so).

The long range match rifles the Army and Marines use in that chambering are capable of 1/4 - 1/2 moa out to between 800 and 1000 meters, and will maintain 1/2 moa maybe just a touch beyond out to 1200. Past 1200 though the precision falls off rapidly as the bullet is too light to retain velocity and cross current resistance, in comparison to the .50.

Added to all these advantages; is that the .338's weigh a hell of a lot less, and KICK a hell of a lot less than the .50 does. A high end .338 sniper rifle is going to weigh between 10 and 15lbs. That same quality and configuration of rifle in .50 (say from McMillan, who makes similar rifles in both chamberings), is going to weight more like 30lbs; and even with the extra weight there's still something between 2 and 3 times the felt recoil impulse with the .50.

Of course I'm nowhere NEAR good enough to make use of this capability:

With good optics, I can generally make solid hits out to 600 meters with a field gun(my longest kill shot ever was over 600), nothing like 1/2 MOA, or even 1 MOA, but good enough to guarantee a kill. From a bench gun, I have no problem with 600m, or even out to 800.

The fact is though, I'm just not still enough for anything beyond it. I can make those 600m to 800m shots with an accurized M14, or Rem 700 in .308 without too much difficulty, but even behind a $4000 McMillan in .338 I can't do anything much beyond it; it's just about the natural limit of what my body will let me do.

Without optics I can get a good chest shoot at about 300, but I'm not really seeing my target properly at that point; I really need to keep it under 200, and prefer keeping it to 100.

Heck, at 100 I can still group decently with good iron sights (gotta be a peep/diopter), at 200 and 300 it's more like a pattern. Though I was good enough to max out expert in qualification, and snag an SAE ribbon (with device no less; I did the same for pistol), that's really not saying much.

I know a bunch of sniper types; let me tell you those cats are unnaturally still; which is what you need for 800-1000m riflery. You have to absolutely control every motion your body makes, including your heart beat and respiration.

I can do the trick; slowing down your heart and breathing, then firing between beats; but even then, I still can't reliably hit anything beyond 800m