Sierra .30 Caliber/7.62MM 175 Grain HPBT Tipped MatchKing (TMK) Load Development and Review: 308 Winchester and Varget

The .30 Caliber/7.62MM (.308) 175 Grain HPBT Sierra MatchKing (SMK) is the gold standard for 308 Winchester precision rifle shooters.  In January 2015, Sierra introduced a .30 Caliber/7.62MM (.308) 175 Grain HPBT Tipped MatchKing (TMK) to expand its offerings to F-Class shooters and tactical match shooters.

According to Sierra:

Sierra has enhanced a segment of the MatchKing line by adding the acetal resin tip, thus crowning the Tipped MatchKing (TMK) bullet line. The major advantage of adding a tip to the bullet is the reduction of drag, producing a more favorable ballistic coefficient.
The 175 grain 30 caliber MatchKing (#2275) was created to allow .308 Winchester shooters to stay supersonic at 1,000 yards.  The popularity this advantage created made adding the 175 grain Tipped MatchKing (TMK) bullet a necessity.  The 175 grain Tipped MatchKing (TMK) bullet is an excellent choice for F-Class (F Open) matches, as well as 3-Gun and various other competitions.
Although the MatchKing line is recognized around the world for record setting accuracy, like their untipped counterparts, Tipped MatchKing (TMK) bullets are not recommended for hunting anything larger than varmints.

Sierra sent a box of .30 Caliber 175 TMKs (part number 7775) to evaluate.  I began by weighing a sample of 50 bullets on an RCBS digital scale.  The results are shown in the table below:

175 TMK bullet weights

Bullet weights ranged from 174.6 to 175.0 grains.  Average weight was 174.7 grains with a standard deviation of .1 grain.

Using a Starrett digital caliper and two Sinclair comparator gauges I measured the bearing surface (the part of the bullet that engages the lands of the rifling) of a 50 bullet sample.

measuring bearing surface

The caliper was zeroed with both comparators in place.  The bullet was inserted into the comparators and the length of the bearing surface recorded.

175 TMK Bearing surface

Bearing surfaces ranged from .400″ to .407″ with an average bearing surface of .403″ and a standard deviation of .002″.  This is .046″ longer than the bearing surface I measured on a 175 SMK (.357″).

I’ve read a few reports of higher pressures in the 175 TMK when compared to the 175 SMK.  While I personally did not observe this, I would suspect the longer bearing surface if accountable for this.175 SMK v 175 TMK

The 175 TMK has an overall length of 1.380″, compared to 1.239″ of the SMK.  The additional .141″ in length effects the OAL of the complete cartridge.  In my 308 Winchester rifle, chambered with a Manson 308 Match reamer, the 175 TMK measured 2.950″ to the lands with the TMK, .070″ longer than 2.880″ capacity of a AICS magazine.  While this isn’t a big deal for a shooter single loading his rifle, such as in F-Class competition, it is problematic with guns using a detachable magazine system.

mag length 175 TMK 308 win, .020 to lands

For testing and evaluation purposes I settled on 2 different overall lengths, one magazine length (above, left) and one single shot (above, right).  The magazine length cartridges overall length is 2.880″ (.070″ from the lands) and the single load cartridge is 2.930″ (.020″ from the lands).

M700 308 Winchester 22 barrel surefire nightforce spuhr right rear 2

The test rifle is a 22″ 308 Winchester with a Shilen barrel and a Remington 700 Action.  The rifle was built with the following parts from Brownells:

If you’d like to read about how the rifle was built, please see:

The Lapua brass I am using has been fired five times in this rifle.  Cases were neck sized, trimmed to length and cleaned in an ultrasonic cleaner.  Charges were dispensed using an RCBS Chargemaster.

Ballistic information was recorded with a Magnetospeed V3 barrel mounted ballistic chronograph.  All velocity information is presented below.

WARNING: The loads shown are for informational purposes only.  They are only safe in the rifle shown and may not be safe in yours.  Consult appropriate load manuals prior to developing your own handloads. and its authors, do not assume any responsibility, directly or indirectly for the safety of the readers attempting to follow any instructions or perform any of the tasks shown, or the use or misuse of any information contained herein, on this website.

With my 175 SMK data as a starting point, I worked up 6 different loads using Varget.

All shooting was done prone, from a bipod, with a rear bag.  Range conditions were 77F, with the sun at 1 o’clock to the firing line.  175 tipped match king 308 varget

308 win 175 TMK load development

175 TMK 308 win .543

Average accuracy was .806″ (.770MOA).  I expected better, however, I feel results would improve with a more intensive load development process.  Both the magazine length and single shot length loads had similar velocities and accuracy performance.  I did not encounter any signs of excessive pressure with these loads.

Velocities were approximately 50 ft/sec faster than the same powder charge with the 175 SMK.  This matches some reports I have read about the TMK being slightly faster than the SMK- however, my 175 SMK data was gathered during the winter when temperature were significantly cooler, I would not predict higher velocities with certainty.

Sierra advertises a sectional density of .264 and a G1 ballistic coefficient (BC) of .545 over 2400 ft/sec.  This is an improvement over the 175 SMK, with an advertised G1 BC of .486 between 1800 and 2800 ft/sec and .505 over 2800 ft/sec.

Bryan Litz of Applied Ballistics, tested the 175 TMK with a G7 BC of .267.  This is nearly a 10% improvement over the 175 SMK with a G7 BC of .243.

Comparing external ballistic performance using a ballistic calculator for the 175 grain TMK and SMK at the same velocity shows the difference in performance at 1,000 yards.  Assuming a 2670 FPS muzzle velocity, the 175 TMK requires 10.4 mils of elevation and 2.6 mils for a full value 10 mile/hour crosswind.  The 175 SMK at 2670, requires 11.4 mils of elevation and 3.0 mils for a full value 10 mile per hour crosswind.  The improvement in downrange performance is significant.

So what do I think of the .30 Caliber 175 Grain HPBT Tipper MatchKing?  I like it.  The round clearly offers a advantage for long range competitors, especially those single loading and shooting F-Class TR competition.  While the length limits seating close to the lands in detachable magazine set ups, initial accuracy was acceptable.  I plan on doing further load development and reporting back.

For more information about the .30 Caliber/7.62MM (.308)175 Grain HPBT Tipped MatchKing (TMK), visit Sierra’s website.


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Last updated 12/7/2015