June 24th, 2012

BMW’s 30,450,000 grain, 227 fps 4-Wheeled Bullet

In a masterful piece of Madison Avenue magic, BMW portrays its M5 “super-sedan” as the four-wheeled equivalent of a speeding bullet. In this clever, CGI-enhanced marketing video, an M5 is “shot” from a giant barrel. It then speeds across the Bonneville Salt Flats towards a giant bullseye — just like a bullet heading toward a target. Along its path, the M5 shatters a giant apple, and then slices through three giant water balloons. Far-fetched? Yes. But the illusion is superbly-crafted, making for two very compelling minutes of movie-making.

Watch BMW Video

Measuring the BMW M5 in Bullet Terms
How does the M5 measure up compared to real bullets shot from real rifles? With a 66.9″ body width, the BMW M5 is a 1700mm projectile. When we convert the M5’s rather porky 4350-pound curb weight* to grains, we find the M5 weighs an astonishing 30,450,000 grains. (Yes that’s 30.45 MILLION). The M5’s electronically-governed top speed is 155 mph. That equates to 277.33 fps — pretty slow by ballistics standards. A typical hunting projectile flies ten times as fast. And even a 9mm handgun bullet travels four times as fast.

M5 ‘Knock-Down’ Power More Than Adequate for Big Game
When it comes to knock-down power, a speeding M5 beats even a 50 BMG bullet hands down. At 500 yards, a 750gr A-Max fired from a 50 BMG has about 8625 foot/lbs of retained energy (this assumes 2700 fps MV).

By contrast, with a terminal velocity of 277.33 fps, the 4350-lb BMW delivers 5.199 Million foot/lbs of retained energy. We think that’s more that enough “hitting power” to cope with any size North American game. But there are certainly some “Zombie” Hunters who might still wish for more power.

How about trajectory? Well we can’t answer that one for you. Last time we checked, Bryan Litz had not calculated the G1 or G7 BC for a BMW M5, so we can’t figure the car’s come-ups using JBM Ballistics. Still, we’re sure that, if BMW gave Bryan an M5 to play with, he’d be happy to spend a few months gathering “data”. But we do suspect it might be a bit challenging to get a 4350-lb sport sedan to fly through the sky-screens of Bryan’s chronographs.

*BMW M5 curb weight based on Car & Driver Report and 7000 grains per pound conversion.
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June 24th, 2012

Dan Lilja Now Offers Pre-threaded Barrel Option ($30 Extra)

Lilja Rifle Barrels prethreadedDan Lilja of Lilja Barrels has announced that, starting this month (June), his company will offer a pre-threading option for in-stock and made-to-order Lilja barrels. The price for the threading option is $30 per barrel. The first offerings will be for Rem 700 actions, and Lilja will, later on, offer pre-chambered barrels as well. Dan tells us: “To begin with we are threading for the Remington 700 actions. Other action types will be added in the future. And we are also planning to offer chambering along with the threading for a limited number of cartridges in the near future.”

CLICK HERE for CAD drawing .PDF file showing pre-threaded Rem 700 barrel shank dimensions.

Details of Pre-Threaded Barrels — Gunsmithing Still Required
Pre-Threading will only be offered, initially, on 28″ or 30″ blanks (length prior to threading). The barrel will NOT be finish-crowned, and Lilja does not offer muzzle threading except for drop-in AR-type barrels. Dan points out that his pre-threaded barrels are not ready to install: “The barrels will still require a gunsmith, experienced at fitting barrels to actions, to make the final fitting and headspacing adjustments on a lathe and using headspace gauges. Lilja will turn these threads for the nominal dimensions for the action type. But action makers have tolerances and other operations such as truing an action face or bolt or lapping bolt lugs can change dimensions enough that headspace or thread shank length may need to be modified.”

Lilja Rifle Barrels prethreaded

Story lead from EdLongrange. We welcome reader submissions.
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