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After completing the 7mm PRC Barrel Length vs Velocity article, the South Dakota prairie antelope season was quickly approaching! I wanted to try a bullet in the 165-175gr range, and it just so happened to be right around the time that Sierra Bullets announced the 7mm 175gr Matchking X.
Sierra’s Matchking bullets are well known for being very easy to tune, which was perfect due to my time crunch. Let’s dive in!
Despite being a new bullet I had a pretty good idea of what powders to use and where to start with the information we gathered in the 7mm PRC Cartridge Guide . I also wanted to add to this information so I kept components as close to the same as possible.
Case: Hornady
Primer: CCI250
Powders:
As with the cartridge guide, we seated the 175gr SMKX 0.030” off the lands. We broke in and put 100 rounds on this new barrel, cleaned, then fouled the barrel with 10 rounds before testing. Velocity readings were taken with a Garmin chronograph.
Projected loads are bracketed in green. Observed pressure signs are highlighted in yellow and red. Shot group pictures correlate with the charge weight charts in that 1 is the lowest powder charge and 10 is the highest powder charge.
Sierra 175 MatchKing X
With all five powders having an area worth exploring, Vihtavuori N560 was the clear winner in this test. H1000 also had a very tight cluster in the pressure ladder, just opening up more on either side of it than N560. The highest charge shot for Ramshot Grand ended up having a slightly heavy bolt lift, and it really threw the shot outside of the group.
Because I will take this rifle antelope hunting, I dove in a bit deeper with this bullet and developed a load using N560. With the barrel cleaned, I loaded up 10 rounds at 68.0gr and fouled it in, letting it cool while loading up 6 rounds at 68.0, 68.5, and 69.0.
My first 3 round group with 68.0gr of N560 wasn’t fantastic. It was twice as big as the two 5 round groups of 68.0gr I used to foul in the clean barrel!
The next 3 rounds grouped quite a bit better, perhaps I was too distracted by the multiple cameras I had running for the YouTube video of these results. Either way, I more than made up for it with the 68.5gr and 69.0gr load!
I chose 68.5gr of N560 as my final load. Shooting in the mid .1’s and low .2’s I didn’t see the need to experiment with anything further. I entered Seirra’s published G1 of 0.597 into my binoculars with a velocity of 3144fps and the dope ran true all the way out to 1100 yards.
| 350 Yards | 0.9 Mils |
| 490 Yards | 1.8 Mils |
| 760 Yards | 3.7 Mils |
| 1017 Yards | 5.9 Mils |
| 1100 Yards | 6.8 Mils |
So why not run the Hornady 175 ELD-X with a .689 G1 or a Berger 175 Elite Hunter with a G1 of .656? Honestly they are both solid options with better BC’s but at 6.8mils to 1100 yards I don’t feel as though I’m missing out ballistically. The Sierra MatchKing X makes tiny groups and held perfect elevation. Even more impressive is the 3 round group on the ram at 1100, which was shot with 3 different shooters, 1 shot each!
The performance of the 175gr MatchKing X on prairie antelope (pronghorn) left a lot to be desired. There was very little to no expansion, and all of the five total shots exited. I took my pronghorn at 500 yards with three shots, the first two showed no signs of expansion with clean, small exit holes and the third shot going through upper leg and a rib, leaving an exit hole that could be covered with a quarter.
Another hunter I had with me landed both his shots at 560 and 640 yards in the upper front leg, with the first exiting the opposite upper leg, and the second exiting near the back of the ribs. Both of those exits are pictured on the right.
While I am very pleased that we were able to recover both of our pronghorn, I had higher hopes for this bullet. It performs extremely well on paper and steel, and with a launch velocity of 3144fps I feel I gave it the best opportunity to perform on game. At this point I cannot recommend it’s use on pronghorn and I would caution it’s use on deer. Perhaps it is better suited for elk and larger game.
Josh Rittel – Production Manager at TS Customs.
