6.5 Creedmoor load development: 16.5 inch barrel, 123 SMK and 140 SMK

6.5 Creedmoor 16.5″ barrel load development for the 123 grain Sierra MatchKing (SMK) and 140 grain Sierra MatchKing (SMK)

When I rebuilt my Savage 10 FCP-SR into a custom 6.5 Creedmoor, I settled on a relatively short, 16.5″ barrel. In 6.5 Creedmoor- Effect of Barrel Length on Velocity: Cutting up a Creedmoor!, I gathered data that indicated a 16″ 6.5 Creedmoor with factory 120 grain ammunition still shoots inside my 22″ 308 Winchester with 175 SMK out to 1,000 yards. While a short barrel doesn’t bring the 6.5 Creedmoor to its full potential, it does make for a fun gun to shoot!

The rifle was built with the following parts from Brownells:

All shooting was done prone, from a bipod with a rear bag. Temperature was 50F. Velocities were recorded with a MagnetoSpeed barrel mounted ballistic chronograph. Target distance was 100 yards.

I selected the 123 and 140 grain SMKs for this round of testing. I have had great luck with the 123 and like it a lot. On the heavier end of the spectrum, I’ve done a lot of work with the 142, however, don’t have as much experience with the 140, so I decided to give that a try.

Deciding on how to approach load development is always a challenge for me. I like larger samples as I feel they are more telling, however, they burn powder and bullets. Since my 123 SMK is dwindling, I elected to shoot 3-rounds of each load. For the 140 SMK, I shot five round groups because I have an ample supply of bullets.

I selected IMR 4064, Varget and H4350 powders for the 123 SMK loads, and H4350 for the 140 SMK loads. I am familiar with these powders and use them often.

I used once fired Hornady brass that was sized with a Redding bushing die. Primers were seated by hand, powder charges were measured with a Harrells Culver powder measure and the bullets seated on a Forster press.

Prior to firing the load development groups, I fired 5 rounds of Hornady factory 120 grain AMAX ammunition as a control. I recorded a velocity of 2774 feet/second with a standard deviation of 19.6. Group size was 1.219″.

For reloading information: 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.

123 SMK and IMR 4064

Note the first group, located on the top left was a 5-shot control group fired with Hornady 120 AMAX factory ammunition. Some of the 123 SMK with IMR 4064 showed promise, however, the velocities were a little lower that I liked.

123 SMK and Varget

Varget is a great powder for many shooters. It is easy to meter and versatile in many different cartridges. The 38.6 and 38.9 grain loads did very well accuracy wise, however, velocities with a little over 100 feet/second less than the factory Hornady ammunition.

123 SMK and H4350

H4350 yielded the highest velocities recorded with the 123 SMK, however, the loads were particularly accurate. I experienced the same findings when I was developing 123 SMK loads for my 22″ 6.5 Creedmoor.

140 SMK and H4350

The 140 SMK didn’t shoot as well as I had hoped. The best load, 41.5 grains, had a velocity of 2494 feet/second and held within .75 MOA.

Best group, but it was only 3 shots….

The 38.9 grain load looks promising, since I only shot a 3 round group it needs more vetting. I loaded up 25 cartridges and head back to the range. I loaded five rounds with overall lengths of 2.700″, 2.710″, 2.720″, 2.730″ and 2.740″. All shooting was done prone, from a bipod, with rear bag.

Temperature dropped to 32F for this stage of testing. Groups ranged from .297″ to 1.064″. The best group, .297″ (.284MOA), was fired with an OAL of 2.720″ (below).