For load development, some guys shoot 3-shot groups. Other guys shoot 5-shot groups, or even 10-shot strings. But for testing its projectiles, Sierra Bullets takes it to another level entirely. A while back Sierra was testing its .30-Caliber 175gr HPBT MatchKing in the Sierra underground tunnel. The results appear above — a FIVE HUNDRED Round group!

500 Shots Form 0.82 MOA Group at 300m (328 yards)
Sierra’s trigger-pullers sent five full boxes of bullets down-range at a single target. The photo above shows the result of 500 shots taken in a 300 meter test tunnel. The raw group size, edge to edge of the farthest shots, is about 3.13 inches, as shown on the calipers’ metal linear scale. Subtract a .308″ nominal bullet diameter* to get the 2.823″ on the digital readout. So you’re seeing a 2.823″ group at 300 meters (328 yards). One MOA at this distance is 3.435″ so this 500-round group is 2.823 divided by 3.435 or 0.82 MOA (0.8218 MOA to be precise).

This 500-round group was shoot as part of a pressure/velocity test for a commercial customer. The cartridge was .308 Winchester, loaded at 2.800″. The powder was Reloder 15. A 26″ barrel was shot from a return to battery rest. The gun was cleaned every 125 rounds and two foulers shot.

What do you think — could you beat this group from a bench for 500 rounds?

One Facebook poster joked: “500-round group? Everyone knows anything less than 1000-round groups are a waste of time and statistically irrelevant.”

Sierra’s 300 Meter Testing Tunnel
Ever wonder how (and where) Sierra tests its bullets? The answer is underground, in a 300-meter test tunnel located under Sierra’s factory in Sedalia, Missouri. The photo above shows the construction of the tunnel back in May, 1990. Like most bullet manufacturers, Sierra does live-fire bullet testing of its projectiles. Sierra’s 300-meter test range is the longest, manufacturer-owned underground bullet test facility in the world. In years past, Sierra offered free visits to the test tunnel as part of a factory tour.

* Normally, to get an exact group size, you should subtract the TRUE bullet hole size, which is usually smaller than the nominal bullet diameter. E.g. a .308 bullet hole may show on paper as .298 or so. But here, for simplicity, we are subtracting .308″ because we do not have the original target to measure.

For load development, some guys shoot 3-shot groups. Other guys shoot 5-shot groups, or even 10-shot strings. But for testing its projectiles, Sierra Bullets takes it to another level entirely. A while back Sierra was testing its .30-Caliber 175gr HPBT MatchKing in the Sierra uynderground tunnel. The results are show above — a FIVE HUNDRED Round group!

The tunnel testers sent five full boxes of bullets down-range. Here are 500 Shots shot in a 300 meter tunnel. The group size is 2.82 inches (that’s edge to edge of the farthest shots, less the bullet diameter). This was a pressure/velocity test for a commercial customer. The Cartridge was .308 Win, loaded at 2.800″.The powder was Reloder 15. A 26″ barrel was shot from a return to battery rest. The gun was cleaned every 125 rounds and two foulers shot.

What do you think — could you beat this group from a bench for 500 rounds?

One Facebook poster joked: “500-round group? Everyone knows anything less than 1000-round groups are a waste of time and statistically irrelevant.”

Sierra’s 300 Meter Testing Tunnel
Ever wonder how (and where) Sierra tests its bullets? The answer is underground, in a 300-meter test tunnel located under Sierra’s factory in Sedalia, Missouri. The photo above shows the construction of the tunnel back in May, 1990. Like most bullet manufacturers, Sierra does live-fire bullet testing of its projectiles. Sierra’s 300-meter test range is the longest, manufacturer-owned underground bullet test facility in the world. Sierra offers free tours of the test tunnel as part of Sierra’s Factory Tour Program.

Sierra Bullets — How It Got Started

Report Based on Story by Carroll Pilant, Sierra Bullets Media Relations Manager
What became Sierra Bullets started in the late 1940s in a Quonset hut in California. In 1947, three aircraft machinists, Frank Snow, Jim Spivey, and Loren Harbor, rented machine space to produce rivets for the aircraft industry along with fishing rod guides and rifle front sight ramps. In the post-WWII years, sport shooting was becoming hugely popular, but quality ammunition was in short supply. For shooting enthusiasts, reloading was the solution to the ammo supply shortage. Snow, Spivey, and Harbor recognized this, creating Sierra Bullets to help fill the void. Before long, they were selling a 53-grain match bullet to the Hollywood Gun Shop. These bullets are still in production today as the Sierra #1400 53-grain MatchKing.

A few years later, an accomplished competitive shooter named Martin Hull joined Sierra. Hull helped develop new bullet types and served as manager of Sierra’s ballistics laboratory for nearly 20 years. With Hull’s help, Sierra’s output grew rapidly. The California company outgrew several locations before it moved to a large facility in Santa Fe Springs, CA, in 1963.

New Owners and New President in the Late Sixties
In 1968, the Leisure Group bought Sierra Bullets. Other Leisure Group companies included Lyman Reloading, High Standard Manufacturing Company, Yard Man, Thompson Sprinkler Systems, Flexible Flyer Sleds, and Dodge Trophies (Which made the Oscar and Rose Bowl Game trophies).

Soon after purchasing Sierra, the Leisure Group hired Robert Hayden as President and General Manager. Hayden was a mechanical engineer who had worked for Remington Arms. Hayden remained the president of Sierra for 42 years, retiring in 2012 when Pat Daly became president.

Sierra Moves to Missouri
In 1990, Sierra relocated to Sedalia, Missouri, where the company remains today. Sierra Bullets now employs over 100 people including five full-time ballistic technicians who answer daily reloading and firearms questions by both phone and e-mail.

The Making of MatchKings — How Sierra Produces SMKs

All Sierra bullets begin life as a strip of gilding metal, an alloy consisting of 95% copper and 5% zinc. To meet Sierra’s strict quality requirements, the gilding metal requires three times more dimensional and quality control standards than is considered standard in the copper manufacturing industry.

A blanking press stamps out a uniform disc and forms the cup that will be drawn into the MatchKing jacket. The cup is then polished and sent to a draw press to be drawn into a jacket that is longer than needed for the future MatchKing, thus allowing for the trim process. Press operators constantly check concentricity to make sure we have only quality jackets. The jackets then go to a trimmer where they are visually inspected again.

After being polished a second time, the jacket travels to the bullet press. In the meantime, 80-pound lead billets are being extruded into lead wire for the cores where great care is taken so that the core wire is not stretched. The core wire is lightly oiled before continuing to the bullet press to be swaged.

The lead core wire and trimmed jacket meet at the bullet press where the first stage forms a boattail on the jacket. The lead core is then formed on top of the bullet press and fed down into the jacket. In one stroke of the press, the MatchKing is formed.

Quality control technicians pull samples from each lot of MatchKings to make sure they meet Sierra’s stringent standards. Samples are then sent to Sierra’s 300-meter underground test range (shown below) to be shot for accuracy on mechanical mounts referred to as “unrestricted return to battery rests” that Sierra designed and built in-house.

After inspection, the bullets are placed in the familiar green box along with reloading labels. They are then shrink-wrapped and shipped all over the world.