6.5 Creedmoor loads: 6.5 mm 150 gr. Sierra MatchKing (SMK)

6.5 Creedmoor loads: 6.5 mm 150 gr. Sierra MatchKing (SMK)- go long!

Sierra Bullets sent me some bullets that were so new they had literally just come straight off of the press.  Sworn to secrecy, I was sent an unlabeled box of the new 6.5mm 150 grain Sierra MatchKing (SMK) #1755.  Reminiscent of the 6mm 110 and 7mm 197, the 6.5 150 is long and sleek with a 27 caliber ogive.  This bullet begged to be shot.


For the 6.5 Creedmoor (guys, it isn’t 6.5 CreedMORE), I’m a big fan of the 123 and 142 SMK.  Both have helped me through a number of matches and produced impressive groups on paper.

The 150 SMK has advertised, banded G1-ballistic coefficients (BC) of .713 at 1,760 feet/second and above, .686 between 1,240 and 1,760, and .621 at 1,240 and below. Pretty impressive stuff.

These (above) are my favorite 6.5mm bullets (left to right), the 123 SMK, 130 TMK, 140 SMK, 142 SMK and 150 SMK.  Note the relative length of the 150!  This is the only downside; with a nominal length of 1.5″, Sierra recommends a 1:7.5″ twist- but, a 1:8″ might work…

Before we get to the good stuff, take time to read the following disclaimer:

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.  Rifleshooter.com 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.

The 150 SMK is LONG!  In my test 6.5 Creedmoor rifle, an overall length of 2.935″ has you at the lands.  To work with a magazine it required an overall length of 2.860″ for a .075″ jump.  So, for testing I decided to work up some loads at this length.

In addition to loading to magazine-length,  I wanted to see how these bullets would perform when they had a slight jam (.005″), so I worked up four loads at an overall length of 2.940″.  These are strictly a single feed item, I’d imagine that most Creedmoor shooters are running some variant of an AICS magazine, but you never know, there could be that one guy who isn’t.

As stated earlier, Sierra recommends a 1:7.5″ twist.  I emailed a couple of barrel makers to see if anyone could get me one cut and shipped in under a week; but, as you can guess, that didn’t work out (didn’t hurt to ask).  I figured I’d shoot them in my 8″ twist rifle and provide some velocity data and maybe one good group.

This is my hammer of a Creedmoor.  One of the best shooting guns I’ve ever had.

I built it with parts from Brownells, including:

All the parts; the barrel, chassis, scope and trigger, work well together for a nice shooting rifle- even if it only has an 8″ twist.

I’m actually in the process of switching the AI AX chassis over to an MDT ESS, I’ve been shooting the ESS a lot lately and have grown quite fond of it! (Click here to learn more about the ESS)

I worked up some loads with H4350 over some 1XF Norma brass.  All shots were fired prone, from a bipod and rear bag.  Ballistic data was recorded with a MagnetoSpeed V3 barrel mounted ballistic chronograph.

Not too bad for an 1:8″ twist?  I’m impressed.

Muzzle velocity ranged from 2,579 to 2,773 feet/second and standard deviation ranged from 6.5 to 20.4 feet/second. Five shot group sizes ranged from .339″ (.324 MOA) to 1.062″ (1.014 MOA) with an average group size of .716″ (.684 MOA)!  (Mr. 7.5″ twist: call your office)

Let’s grab the iPhone and run some numbers in the ballistic calculator to see how they compare to my old favorite, the 142 SMK.  When modeled with banded G1 BCs (Sierra owns a Doppler radar and Litz even agrees that their advertised banded BCs are accurate), assuming standard temperature & pressure, the 142 SMK from the same gun runs at 2,768 feet/second and requires 9 MRAD of elevation at 1,000 yards with 2.1 MRAD of drift in a 10 mile/hour crosswind.  The 150 SMK from the same gun loaded mag length with a velocity of 2,720 feet/second and only requires 8.3 MRAD of elevation and  1.7 MRAD of drift for the same conditions at the same distance.  I’m sold. I need more… and I need some 7.5″ twist tubes!

So what’s next?  Clearly, I need to start pushing the 150 SMK out farther, especially with an 8″ twist.  If we can keep these performing with an 8″ twist at range, we might not have to go out and buy a bunch of 7.5″ twist barrels for our Creedmoors!

I’m also planning on shooting it in my newest Creedmoor, a custom Howa 1500 in an KRG XRAY 180 chassis.

This is a pretty neat build that I’ll be posting on shortly.  It includes the following parts from Brownells:

I’m running a Zeiss V6 5-30x50mm scope.  This is a great rifle!

Zeiss has sponsored rifleshooter.com.  They make quality optics for the sport shooter.  If you get a chance, please check them out here.

To learn more about the Sierra 150 gr SMK, click here!