Reloading Press: .416 Barrett (10.6x83mm)

The Reloading Press is an at-least-weekly feature here on Gaming Ballistic for 2016. Each week it looks at some interesting real-world cartridges and presents them with hopefully-useful information in GURPS Format.

.416 Barrett (10.6x83mm)

I was laboring under the impression that the .416 was just a .50BMG necked down to .416. This proved to be incorrect - at least to a certain extent.

The design philosophy was more or less to unapologetically design a purpose-built long-range sniper cartridge for work at the very long engagement distances that US troops were encountering. The bullet itself was targeted for weight (about 400 grains) and turned down from solid brass on CNC machines. While this is more expensive, it makes for a very high ballistic coefficient (0.74) and the manufacturer claims that it stays supersonic well past 1500 yards (I believe it).

The entire purpose of this one was to deliver a supersonic projectile at over a mile, to enable very accurate shot placement. That's a bit beyond the scope of the ballistics calculator . . . but this projectile is a monster. It's a projectile that masses 6x what the current M855 does, but travels every bit as fast. As you'd imagine, it makes quite an impression
Ballistic's Calculator Inputs

Basic inputs for the calculator are as follows, selecting 810mm for the barrel length.

INPUT
	.416 Barrett
Chamber Pressure	57000	psi
Barrel bore	10.6	mm
Case Length	83	mm
Chamber Bore	18.6	mm
Barrel length	810	mm
Bullet Mass	398	grains
Aspect Ratio	4.62	L/Bore
Burn length	26.86	mm
Projectile Caliber	10.6	mm
Total Accelerated Mass	398	grains
Expansion Ratio	1	expansion
Projectile Load	1

Output Stats

The entire platform was designed around the 810mm barrel of the M99 single-shot platform.

Notes

• The velocity is at the muzzle. The velocity with a 810mm (almost 32") test barrel is tuned to match real-world data at 3,150fps with a 395gr turned-brass bullet. 
• With damage as high as it is, I didn't do the point-by-point barrel lengths, since the difference between 12d and 12d-1 is in the "who cares" range.

There are not too many barrel lengths out there. There's the standard 810mm barrel, and a few others from different rifles.

They're all long, though. While this projectile/cartridge combination would benefit from a bullpup configured rifle, the test barrel coming in at about 32" means this thing is a beast no matter what. And past the 740mm to 840mm range where 12d-ish happens, you're really not helping yourself much (two extra points of damage? Why bother?).

Alternate Loads

While there may be alternate bullets, and I did read that cheaper jacketed lead bullets were "forthcoming," as far as I could find, there's but one projectile here - the turned-down brass solid bullet. 

Platforms

Barrett M82A1

The basic platform that is the test platform is the single shot M99, which will run you about $4,000.

Barrett M99 Single-shot

The M82A1 gives you a box magazine likely of 10 rounds, and is nearly $9,000 . . . and that's without an optic, on which you'll want to drop a whole lot of money, because why get a rifle that can reach out over a mile if you can't see the target?

McMillan TAC-416

Finally, if you don't want Barrett, you can go McMillan or Armalite. The Armalite is a $2,500-$3,000 rifle (again, no optic). The TAC-416 is hard to find and harder to find pricing for, but the 50-cal version seems to run around $10,000. Yow.

These are special platforms for special applications, and amateurs need not apply. Or they shouldn't. But for the truly needful, and truly rich, you can nab a system that has validated 0.4 Minutes of Angle capability. The math puts Acc 7 for a GURPS rifle at about 0.36 MoA so basically, drop $10K on a rifle, another $4K for a Schmidt and Bender scope, and then any other customization you want, plus the ammunition (which after that is the least of your worries).

Tags : #Guns and Shooting#GURPS#Reloading Press

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