6.5 Creedmoor loads: 107 SMK IMR 8208 XBR and 142 SMK Superformance
6.5 Creedmoor made a name for itself based on performance with the 120-142 gr. class bullets. Unlike older cartridges such as the 308 Winchester or 30-06 Springfield, both of which have decades under their belt (and created before most of us were born), the 6.5 Creedmoor is still a new comer. In this post I wanted to take a look at how the Creedmoor did with a light, 107 gr. bullet and then take a look at an old favorite, the 142 SMK with the newer Superformance powder.
I’m running the custom Remington 700 I built with parts from Brownells, including:
- Remington 700 short action receiver with “upgraded” one piece bolt
- Proof Research 6.5 mm 1:8″ twist Sendero contour stainless steel barrel
- Accuracy International AICS AX chassis
- Timney Calvin Elite 2-Stage trigger
- Badger Ordnance Maximized scope base
- Spuhr ISMS scope mount
- SCHMIDT & BENDER – PMII/LP/MTC/LT 5-25X56MM SCOPE LOCKING TURRET FFP ILLUM. MSR
This rifle really makes me happy. I build a lot of different rifles for myself. Invariably I wish I had done something different, maybe changed something on the stock or the barrel length, that is not the case with this rifle. I am extremely pleased with it.
Before we get to the good stuff, please take time to read the following disclaimer about reloading:
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.
I selected IMR 8208 XBR for the 107 gr. SMK in the 6.5 Creedmoor. I have a bunch of friends that swear by it in the 223 Remington, so I figured it was worth a shot. For the 142 gr. SMK I wanted to try something new, so I ordered up a pound of Hodgdon/Hornady Superformance powder. Superformance powder advertises higher velocities for given cartridges. I’ve never shot it, so decided to give it a shot.
The image above shows three 6.5mm (.264″) Sierra MatchKings (SMKs), the 107 gr, 123 gr and 142gr. Note the 107 gr is nearly as long as the 123!
I’m using 3XF Norma brass. This is a solid step up from the factory Hornady brass with far better consistency and quality control. I used a Redding Competition bushing neck sizing die with a titanium nitride coated bushing. This type of die doesn’t use a case mouth expander and provides for less run out. Powder charges were measured with a RCBS Charge Master and bullets are seated with a Redding Competition match seating die in a Forster press.
All shooting was conducted prone from a bipod with a rear bag. A MagnetoSpeed V3 barrel mounted ballistic chronograph was used to measure muzzle velocity.
The Sierra 107 gr. SMK #1715 has banded G1 ballistic coefficients (BC) of .430 @ 3350 fps and above, .420 between 3350 and 2800 fps, .406 between 2800 and 2300 fps, .395 between 2300 and 1800 fps, and .385 @ 1800 fps and below.
Muzzle velocity for the 107 SMK with IMR 8208 XBR ranged from 3,108 to 3,205 feet/second with standard deviations ranging from 10.1 to 29.1 feet second. Five shot group size ranged from .402 (.384 MOA) to .884″ (.844 MOA) with an average size of .642″ (.613 MOA). The most precise group, .402″ (.384 MOA) was achieved with 39.9 grains of IMR 8208 XBR.
The Sierra 142 SMK has a banded G1 BCs of.626 @ 2850 fps and above, .611 between 2400 and 2850 fps and .606 between 2050 and 2400 fps.
Muzzle velocity for the 142 SMK with Superformance powder ranged from 2,883 to 2,966 feet/second with standard deviations ranging between 14.5 to 25.3 feet/second. Five shot group sizes ranged from .186″ (.178 MOA) to 1.214″(1.160 MOA) with an average groups size of .704″ (.672 MOA).
I have to admit I was floored by the last group I shot with the 142 SMK over Superformance. That’s five rounds, prone, from a bipod with a rear bag with a center to center group size of .186″ (.178 MOA)! Wow! Plus the velocity was an impressive 2,966 feet/second, 198 feet/second FASTER than the fasted H4350 load I fired through the same rifle a few days before. The upside of the Superformance powder was the velocity, however, looking at the standard deviation of the rounds and the one large group, I’m not quite sure I’ll be replacing the H4350 yet.
The 107 SMK was a fast, neat little load with very little recoil that deserves consideration if that weight class of bullet will meet your needs. I modeled it using Litz’s G7 BCs and came up with a drop of 6.7 MRAD at 1,000 yards with 1.9 MRAD of drift in a full value 10 mile/hour crosswind. Compared to a 123 SMK at 2,964 feet/second with 8.3/2.3 MRAD and the 142 SMK at 2,768 with 8.9/2.1, it seems like the 107 will get there. The obvious downside is the decreased effects on target, if you shoot heavy steel, I’m unsure how much it will move.
I’ll keep shooting and let you know how it goes!