Sierra Tipped MatchKing
In the field - Doc Watson
I have to say I'm quite a big fan of Sierra bullets. The MatchKing line in particular has always impressed me, but not because of anything flashy or super slick.
I like them because they shoot. Period.
Generally speaking, if I'm having trouble with a gun I'll load up Sierra MatchKings and make an attempt to prove the rifle using these, and more often than not if a rifle has promise it will shoot its best using the correct weight SMK. This is not uncommon, and I know a lot of hand loaders chasing accuracy have had great results with the SMK so I also know a lot of shooters and hunters who are hanging out for Sierra’s new Tipped MatchKing line.
For me the main reason for the anticipation is the potential to be able to shoot a bullet that’s as accurate as the traditional SMK but has the benefit of controlled expansion at long range - that is to say low velocity.
The method of testing I decided to use was to take two different rifles to the bench, and first shoot the original SMK and then shoot the same weight TMK back-to-back, and compare groups.
The second stage was testing the expansion of these projectiles on game at close and extended ranges. Obviously if the projectiles performed badly during the first part of the test we wouldn’t even make it to the second!
This type of test is in no way the final word on the accuracy potential of the TMK but I felt it was a relevant starting point given the expectation I had for this new projectile.
I shot them in a standard Sako .300 Winchester Magnum with a heavy 1 in 10 twist barrel. I also shot them in a custom rifle with the same twist. I loaded both the SMK and the TMK to mag length in the Sako and shot two sets of 3 shot groups. I felt it was important to load these this way in a standard rifle in order to give a balanced result.
In the custom rifle, using the AI magazine, we were able to seat the projectiles a lot further out and gained significant accuracy as a result.
It’s interesting to note that the SMK shot very consistently seated both in and out while the TMK preferred a certain depth to give its best; this is not uncommon for a high performance bullet such as this.
You can see from the cross section picture the tip on the TMK is huge. Shown next to the same weight 168gr Hornady A-Max it’s a lot bigger; the gap in the top of the round that houses this tip is almost twice as wide as that of the Hornady.
To me this means one thing ... expansion ... and lots of it. This is good if you want to release energy into the target at long range, but when impacting at high velocity, or close range, results can be somewhat inconsistent.
This proved to be true when shooting this fallow buck with the TMK at 130 yards. In this instance the projectile, while retaining a good amount of weight, did not exit.
Long range results were as expected, with a number of goats getting taken with authority even at velocities as low as 1500 FPS.
Three out of four animals shot past 500 yards saw the rounds punch thru and exit consistently, leaving a fairly broad wound channel.
Sierra has not claimed the TMK to be a hunting round - in fact quite the opposite - and with the thin match jacket and large polymer tip promoting rapid expansion it’s unsuitable on anything but light-bodied game at high velocity (inside 300 yards). As always, it’s up to the hunter to use his/her discretion and shoot with this knowledge in mind.
Testfire by John Herbert
Sierra have a new bullet, called the Tipped MatchKing and I have no doubt this one, like previous polymer-tipped bullets, will be of interest to Kiwi hunters. We like our polymer-tipped bullets and comments from importers and retailers make it clear that the sales figures back this up.
Sierra have resisted the trend to go to a tipped bullet in their non-varmint range and their reasoning, as given to me by Sierra VP of Marketing Matt Reams, is that Sierra bullets have a reputation for shooting accurately at various seating depths and that going to a more aggressive ogive could compromise this. Matt has a good point; in testing various MatchKing bullets I’ve found them easy to tune and not particularly sensitive to seating depth. In the May/June issue of Rod&Rifle I discussed bullet seating depth and how bullet ogive shape and seating depth are related. Basically, aggressive secant and VLD ogives are more sensitive to seating depth changes while gentler tangent ogives, as seen on traditional Sierra MatchKing bullets, have less sensitivity to seating depth and may shoot just as well when they are not able to be seated close to the lands of the rifling. Now this last point is quite important, as many of our most popular hunting rifles, especially the short actions (.308, 7mm-08, .243 etc.) have magazines that don’t allow a lot of room when it comes to seating bullets out to get close to the rifling. Traditional soft point bullet designs have shorter tangent ogives and with a short action calibre a max OAL of 2.8 inches still allowed a reasonably short jump to the rifling.
With the trend for higher Ballistic Coefficient bullets, manufacturers used a few tricks to get the BC up without increasing weight. The first was to lengthen the nose of the bullet and give it a more aggressive ogive. To help with the longer nose a bullet can use a lightweight polymer tip, which will also help give a more consistent overall length and a smaller, more consistent, meplat. They also lengthen the boat tail and change the angle slightly. This results in a longer bullet with less bearing surface and, depending on the design, a more abrupt change where the parallel part of the bullet meets the ogive. Sierra have employed both these methods with the 168gr Tipped MatchKing, but say they have worked on the all-important ogive-to-shank shape so it’s less sensitive to seating depth. This has resulted in a big jump in BC between the old and the new MatchKings; the old 168gr SMK had an average BC of .427 while the new TMK has an average BC of .512 - quite an increase - and for long distance shooters this means that out of a 22 - 24 inch barrel the 168gr TMK will be supersonic at 1000 yards while the SMK would go transonic before 900 yards.
It’s worth noting that Sierra use G1 BC figures, and split them into velocity ranges. Many BC solvers will use this BC/velocity banding to deliver a correct solution and while I still prefer to use a G7 BC, as it’s more accurate for modern streamlined bullets, the Sierra stepped BC’s are the next best thing and are generally accurate. (But beware; not all manufacturers are so honest in their BC ratings.)
So the question remains: how do they shoot? Sierra state that these bullets are not designed for hunting, so before Doc checked how they’d go on animals I tested them for accuracy. For this trial, I used 3 loads using 45.5 grains of ADI 2208 (Hodgdon Varget is the same powder) in Norma cases with CCI 200 primers. I varied the seating depth: 15 thousandths off the lands, 50 thou off and seated to 2.820 to just fit inside the magazine of our Remington 700 5R .308 test rifle. The 2.820 length gave quite a big jump - of 180 thousandths. The 5R has proven capable of shooting in the 0.4 -0.7 MOA range for 5 shot groups so I was hoping for good things, although I will state right from the get-go that I’ve had better days on the benchrest. With a howling wind and lungs full of the flu my shooting felt only average and on a different day I’m sure I could have trimmed a bit off the group size. Firstly however, the groups showed that the TMK was not overly sensitive to seating depth, with the 45.5 grain 2208 load at 2.820 shooting a 0.83 inch group, and the long-seated 3.03, 45.5 grain load shooting a very similar 0.84 group. The 2.98 OAL group was just over an inch, but I suspect the high shot was a flyer of my own creation. A later group using the 45.5gr load at 2.820 shot the best group of 0.68 inches. I saw no pressure signs here and going forward I would try it with another 0.5gr of powder to see if I’m getting close to an accuracy node. All groups were 5 shots but many of the 3 shot groups were under 0.5 MOA.
The TMK definitely shot better at one depth but ironically this was at magazine length where it had a significant jump. Every rifle and bullet combination responds differently to seating depth, as Doc Watson found out.
I am looking forward to seeing the rest of the TMK line in New Zealand; the 125gr .30 cal bullet may be just the thing for the 300 AAC Blackout while the 155gr .30 cal and the 69gr .224 will no doubt be very popular with .308 and .223 shooters respectively. The new 168gr TMK gives the traditional 168gr bullet weight a real lift in BC, and as a bonus it shot well seated at magazine length in the .308 Remington 5R.