Sierra Match King 20 Cal .308 175 gr HPBT


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Sierra Match King 20 Cal .308 175 gr HPBT

JWT for TTAG

I am interested in guns. I am fascinated by cartridges. I like the Winchester “Improved Mauser” action. I am enamored with the 7mm-08.

That’s probably why, during a prairie dog hunt with Sierra this summer, I thought of the history and plight of the .308 175gr Sierra Match King bullet with nostalgia and melancholy.

1993 was a rough year. The Brady Bill was signed into law, Islamic fundamentalist terrorists first bombed the World Trade Center, the ATF murdered a bunch of people in Waco, and Beanie Babies were popular.

On the plus side, this gawky kid from the tiny town of Dripping Springs, Texas started college where the female to male ratio was almost 4:1 and the United States Marine Corp adopted the M118 Special Ball Long Range cartridge for their 7.62×51 NATO chambered rifles. The M118LR was born.

Sierra built the new boat tail hollow point (BTHP) round for the cartridge, and named it the 175gr Sierra Match King (SMK). Although the propellant and primer has changed for the M118LR over the decades, the bullet didn’t. The performance of that bullet, along with the well-deserved reputation of the USMC Scout/Scout-Sniper and marksmanship teams ensured the round became synonymous with long-range shooting.

Since then, that 175gr SMK has been around the world, punching holes in paper and Pashtuns alike. It’s been chambered in bolt guns and semi-autos. Its performance and relatively low cost have made it the go-to bullet for many civilian and military shooters alike for decades now.

More perfect bullets than the 175gr SMK exist. There are rounds with more polished jackets, more consistent meplats, and more consistent dimensions (at a cost).

Sierra Match King 20 Cal .308 175 gr HPBT

JWT for TTAG

There are also quite a few bullets of the same caliber and of similar weight with higher ballistic coefficients. Take, for example, the Nosler 175gr RDF, with a G7 BC of .270, the Berger 175 gr Match MTLR with a G7 of .264, or the Hornady 178 gr ELD-M with its very slick .275.

The big advantage there is that the higher BC allows the shooter more error when judging wind at long ranges. And everybody misjudges wind. Some of us just much, much more than others.

The downside is that those bullets often require higher twist rates or have a very specific depth from the rifling lands (or require contact with them) to perform consistently. The SMK doesn’t. A 1:11″ or 1:12″ twist rate will stabilize the SMK just fine, which is likely why so many military rifles continue to be chambered with these twist rates.

A 1:12 twist rate existed long before the .308 caliber SMK bullet or the M118LR cartridge. We see it on US semi-automatic battle rifles going all the way back to the Vietnam war. Back then they shot a 173 gr FMJBT. I imagine that twist rate was considered when making the 175gr SMK, and then the ubiquitous use of the M118LR and the bullet that sits atop it continued to drive the 1:11 to 1:12 rates, but this is purely speculation.

When FN released their SCAR 20S, they put in the same 1:12 twist rate that existed on their previous military-only version Mk20 SSR. That twist rate was chosen because the bullet the military wanted to shoot, the 175 gr SMK, stabilized just fine at that rate. Civilians, who previously demanded a rifle just like the one the military used then wanted to shoot heavier bullets or rounds with a higher BC than the 175gr SMK, so the newer versions of the 20S sport the faster 1:10 twist rate.

Out of curiosity, I grabbed a box of 100 bullets and got to testing them.

A buddy of mine has a shop with a dial indicator used to measure concentricity. I measured a few bullets, but got the same result for all of them. The result was all zeros, meaning that the three zeros right of the decimal place that I could measure weren’t precise enough to give me a solid reading.

Sierra Match King 20 Cal .308 175 gr HPBT

JWT for TTAG

Using a Lyman digital powder scale, I weighed each of the bullets…all 100 of them. The lightest round measured 174.6. grains. The heaviest round measured 174.9 grains…and almost all of them weighed 174.9 grains. There were so many 174.9 rounds that, when measured to the nearest tenth of a grain, both the median and the mean were 174.9 grains.

One of the very nice things about 175 gr SMK is that it has been around for a while and a large amount of data is readily available for it. If I plugged a G1 BC of .505 into my ballistic calculator, and shot out to 800 yards, I’d get an estimated 229″ of drop. But that’s wrong. In reality, my bullet is only going 2,437 fps from that Remington 5-R‘s barrel (measured at the time of testing), and all of my rounds are landing just a little bit off, considering this gun and ammunition’s 1/2 MOA precision capability.

Looking at Sierra’s published data, my round is going much slower than the 2,800 fps that .505 BC is based off of. Using the correct .496 and .495 numbers, I arrive at 236″ of drop, which is, oddly enough, where my bullet is actually landing.

If I wanted any additional data about the SMK, including applications, performance, really anything at all, I could call the Sierra Tech line at 800-223-8799 five days a week, 7am-7pm. That’s a real thing. You can call their tech line and speak to an actual person who actually knows about the bullets.

I had no reason to do so other than to just verify that it has some value, and yeah, there are really people who pick up the phone and can answer questions. Sierra isn’t the only bullet company to have technical/product support. Most do, but by email or online form. Few have technical support phone lines available and staffed so well. And none that I know of with such a large and varied production line.

There are some smaller companies that supply this kind of customer service, like Berger Bullets. When that company first started gaining traction, my emails were promptly and comprehensively answered by Brian Litz. Back before ballistic applications included a “Litz” category for BC, some of my computations had “Per Litz” listed next to them, because those are the values he included in his emails to me. One of those is the .243 G7 BC of the 175gr SMK. That’s right, no matter who you are and what bullets you make, you’ve spent some time on the 175gr Sierra Match King.

All that, and putting so so many of them through metal tubes, is why I am so nostalgic for the 175 gr SMK. My melancholy comes from the realization that the 175 gr SMK’s reign is near its end.

The 6.5 Creedmoor already been adopted by SOCOM, but FN and others are offering some of their previosly 7.62 NATO only machine guns in the 6.5 Creedmoor as well.

That’s just an intermediate measure for some units while the real change is taking place. The new 6.8mm round and its parent super space cartridge are moving forward through the DoD systems and are destined to be the military’s new go-to for all things near(ish) and far(ish).

Eventually, civilians will follow suit, and the round once used as the standard for long-range military shooting will go the way of black powder and metal butt plates.

Which means I’ll still be shooting it, right next to whatever new X.fancymm intergalactic telescopic polymer cartridge was just released to the inner planets.

“Gather round, kids, and let grandpa tell you about slow, fat bullets, and the men who loved ’em.”

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