6.5 Creedmoor loads: 142 gr. and 140 gr. SMK with H4350

6.5 Creedmoor loads: 142 gr. and 140 gr. SMK with H4350

I hate to say it, but I guess I drank the 6.5 Creedmoor Kool-Aide. I’ve posted quite a bit of load development for the 6.5 Creedmoor with 16.5″, 22″ and 24″ barrels. But I never presented data for a 26″. Well, let’s fix that in this post!

This is my test gun. You may recognize it from a couple of other posts, in particular A look at how rifle barrels speed up: Measuring the increase of muzzle velocity in new barrels. I built it with parts from Brownells, including:

I really like the way the rifle turned out. All the parts, the barrel, chassis, scope and trigger work well for a really nice shooting rifle.

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.

For bullets, I selected the Sierra 6.5mm 140 gr. and 142 gr. MatchKings (SMK).

You’ll note the 140 gr SMK (left) is shorter than the 142 gr SMK (right). The 140 gr SMK has banded G1 ballistic coefficients (BC) of .535 @ 2800 fps and above, and .526 between 2800 and 2000 fps, while the 142 SMK has BCs of.626 @ 2850 fps and above, .611 between 2400 and 2850 fps and .606 between 2050 and 2400 fps. It seems like selecting the 142 gr over the 140 gr would be a no brainer, but there had to be a reason that Sierra offers both. To answer this, I reached out to Sierra Bullets.

According to Sierra:

The #1740 140 MK bullet is often selected as a good choice for a long range bullet in those firearms that are barreled with slower twist barrels. For years the .260 Remington rifles made when it was first introduced came out with 1×9″ twist barrels. The 140 MK did very well in those rifles. The #1742 142 MK really needs a barrel twist rate of 1×8″for good stability.

The #1740 140 MK also had a more “standard” tangent ogive that can be a bit more forgiving when trying to determine an OAL for accuracy. Being very similar to the #1730 140 SBT GameKing, it was a very easy transition when switching from a target load to a hunting load in a dual-purpose rifle.

The #1742 142 MK of course has a considerably higher BC value than does the #1740. This in turn provides a noticeably flatter trajectory at extended ranges.

Both bullets have proven to be extremely accurate and continue to provide excellent results. There are valid reasons for each bullet.

The 140 gr SMK has the advantage of potentially be forgiving during the load development process and more compatible with slower twist 6.5 rifles. My own experience mirrors this, finding it slightly easier to tune than the 142 gr SMK.

Hodgdon H4350 seems to be the popular powder choice for heavier bullets in the 6.5 Creedmoor, so this is the powder I selected. Brass is 1XF Norma, neck sized in a Redding full length neck size die with a .291 titanium nitride bushing. Powder charges were dropped with a RCBS Chargemaster. A Redding competition seat die was used to seat the bullets on a Forster single stage press. Tula primers were seated by hand with a Sinclair priming tool.

Seating depth of the bullets was .020″ short of the ogive touching the rifling, 2.810″ OAL. To measure the distance from the bullet’s ogive to the lands, I used a Hornady OAL gauge. As a rule, I don’t like to jam bullets into the rifling.

All shooting was done prone, from a Harris BR bipod equipped with a Pod-Lok, with a rear bag. Temperature was 80F and it was a sunny day.

Velocity information was collected with a MagnetoSpeed barrel mounted ballistic chronograph.

Overall the results for the 6 different loads I tested for the 142 SMK were quite good. All 6 were sub 3/4 MOA, four were sub 1/2 MOA and one was sub 1/4 MOA. The average five shot groups size was .547″ (.522 MOA). The 142 SMK 40.8 gr. H4350 load hammered. Really happy with this one.

I only ran four shot groups for the 140 SMK. In this case, all five loads were sub 3/4 MOA and three were sub 1/2 MOA. Average group size was .442″ (.422 MOA)! Note two of the loads had single digit standard deviations.

It looks like I found two bullets that shoot really well in this rifle. I’ll be doing more fine tuning with the 142 SMK in the 40.5-41.1 gr. range and that will hopefully end up being my load for this rifle.

Sierra now publishes 6.5 Creedmoor load data, to see it, click here!