TESTED: Sierra 6mm 105-Grain MatchKing (Exceptional Results!)

Sierra Bullets made a big splash with the launch of their new 6mm 105-Grain MatchKing HPBT bullet this year, building on the success of their 107-grain SMK. We put this bullet to the test, both on the range and in the lab, with astounding results. Watch the full video and read on for the details!

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About the Sierra 6mm 105-Grain MatchKing

105-grain bullets have grown in popularity, especially for PRS. 6mm’s mild recoil is ideal for seeing trace, hits, and misses and has a wide range of available cartridges.

I was eager to test the new Sierra 6mm 105-Grain MatchKing following the continued success we have had with Sierra’s 6mm 107-Grain HPBT bullet.

The Sierra 105-grain MatchKing has a G1 BC of 0.577 and a G7 BC of 0.284. These are a marked improvement over the BC’s of the 107-grain MatchKing (G1: 0.547, G7: 0.262).

The new 105-grain SMK requires a 1:8 twist or faster, making it ideal for 6mm Creedmoor, 6mm x 47, 6BR, 6 Dasher, 6 GT, and 6mm ARC.

From Sierra Bullets:

This bullet is a popular choice for across-the-course and long-range target shooters. It was engineered with a long ogive, small meplat, and optimized boat tail to preserve downrange efficiency, enhance accuracy, and reduce wind drift.

Renowned worldwide for record-setting precision, MatchKing® and Tipped MatchKing® bullets are designed strictly for target shooting and are not recommended for most hunting applications. While they are sometimes used for varmint hunting, their construction does not provide the same reliable explosive expansion at comparable velocities as lightly jacketed Hornet, Tipped VarmintKing, or VarmintKing bullets.

A barrel twist rate of 1×7.5″ or faster is required.

Lab Tests

Kyle Shields took a series of precision measurements from a sample of ten Sierra 105-grain bullets.

He used a FX-120i scale with a 0.02 grain resolution to weigh each bullet. The average weight was 104.994 grains—only 0.006 grains short of 105.000! These bullets showed even greater weight consistency than the Sierra 107-grain MatchKings we previously measured (avg. 106.943 gr.), making this session’s results the best weight consistency we’ve ever seen! The weight standard deviation was 0.044 grains with an extreme spread of 0.140 grains.

The average diameter was 0.243” with an SD of 0.00004” and ES of 0.000”.

Length was less consistent but still good with an average of 1.2540”, SD of 0.0037”, and ES of 0.0126”. Length is generally less consistent with hollow-point bullets due to the way the tips are formed in manufacturing.

The weight and diameter consistencies were absolutely exceptional and worth paying attention to!

Testing Across Three Different Calibers

I decided to shoot the new 105-grain SMK in three different custom bolt-action rifles.

Cartridges Under Test – 6mm Creedmoor, 6×47, 6mm ARC

6mm x 47 Lapua

My 6mm x 47 features a BAT Hammerhead action with 75-degree bolt throw in a WOOX Furiosa Ultra chassis (ULTIMATERELOADER10 to save 10%) with Hawkins Precision M5 DBM, and a Leupold Mark 4HD 6-24×52.

I loaded the 6mm 105 SMK over 36.0 grains of Hodgdon’s H4350 in 6mmx47 Lapua brass with a Federal small rifle primer.

My first five-shot group at 100 yards measured 0.331” with an average velocity of 2748.9 fps and 13.8 fps standard deviation. This was a relatively-mild load and I’m confident that with load development I could achieve groups in the 0.2” range with a tighter SD.

Wanting to reach out further, I validated my dope on a steel rock chuck target at 335 yards before transitioning to a more challenging target at 706 yards.

This target is exceptionally difficult to see with snow on the ground as it is painted white. My first shot was a miss. I couldn’t see my shot, but I did note a wind coming from the left. Holding the left edge of the target resulted in four consecutive hits!

This on-target success is a true testament to the accuracy of Sierra’s data. I took their BC, entered it into a ballistic calculator, and was spot-on elevation-wise at 706 yards.

6mm ARC

Using the same 6mm ARC bolt-action rifle I used for my recent 6mm ARC high-pressure test, I loaded the 105 SMK over 27.1 grains of IMR 8208 XBR in Peterson brass with a Federal small rifle primer.

This powder has previously performed very well with the Sierra 6mm 107-grain HBPT.

After considerable load development with the 107’s, I achieved a five-shot group at 100 yards measuring 0.244”.

6mm ARC Results with Sierra 107 Grain MatchKings

This rifle is centered around a BAT TR action with a 1:7.5 barrel, TriggerTech Diamond 2-stage trigger, and Leupold scope.

With the 105-grain bullet, five shots at 100 yards measured 0.594” with an average velocity of 2748.2 fps and SD of 12.5 fps.

This is very close to the 2750 fps nominal velocity I’ve seen listed on various boxes of factory 6mm ARC ammunition. This group was larger than I would like, so I swapped the titanium muzzle brake on the rifle for a heavier steel brake and increased the powder charge to 27.4 grains of IMR 8208 XBR.

I was much happier with the results of the second load/configuration. The average velocity was 2767.4 fps with a standard deviation of 2.1 fps!!! Five shots at 100 yards measured 0.487”, sub-half-MOA.

6mm Creedmoor

For our last test, I had Kyle Shields bring out the HOWA 1500 6mm Creedmoor I had previously accurized.

I fully rebuilt and rebarreled the rifle, using a reamer from JGS custom for a custom freebore.

We called this the 6mm Creedmoor UR.

Kyle combined 40.5 grains of Vihtavuori N555 with the 6mm 105-grain SMK, Peterson brass, and a Federal small rifle primer for a five-shot group measuring 0.394” at 100 yards.

6mm Creedmoor Group with Sierra 105-Gr. MatchKing

The SD was 11.2 fps, very close to my desired 10 fps threshold for long range shooting, and the average velocity was 2965.6 fps.

Kyle found this “accuracy load” in a PDF version of Sierra’s reloading manual.

Conclusion

I’m completely sold on these bullets and will definitely be loading more of them.

Across all groups fired, the average five-shot group size at 100 yards measured an impressive 0.431 MOA—well under the 0.5 MOA mark. This was achieved with virtually no load development beyond a minor powder charge adjustment and a muzzle brake swap on the 6mm ARC.

Our lab results confirmed that Sierra’s 105-grain bullets are manufactured with exceptional consistency. Additionally, Sierra’s published ballistic coefficient proved to be highly accurate, as demonstrated by the spot-on elevation at 706 yards generated by my ballistic calculator. This is a great bullet for a variety of 6mm cartridges — what will you be loading them in?