I’ve had great luck with the 142 grain Sierra MatchKing (SMK) in my custom rifle chambered in 6.5 Creedmoor. A few posts I’ve read on various forums reported exceptional accuracy with short cartridge lengths placing bullet relatively far away from engaging the lands. I decided to test the 142 grain SMK in .040″ OAL intervals to see how length would effect accuracy.
My 6.5 Creedmoor rifle is built with the following components from Brownells:
- Surgeon 591 action
- Bartlein 6.5mm 1:8 twist HV barrel
- Badger M5 bottom Metal
- Timney 510 trigger
- McMillan A5 stock
To see how I built the rifle, check out Building a Custom 6.5 Creedmoor Precision Rifle.
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.
Hodgdon H4350 has been an excellent performer in my 6.5 Creedmoor. Changes in bullet seating depth can and will effect the pressure a round will generate when fired, so care must be taken selecting a load. In this case, I selected a moderate load of 40.8 grains for my testing.
Brass is 3XF Hornady, neck sized in a Redding full length neck size die with a .290 titanium nitride bushing (note: the I did not use the FL die to set back the shoulder). The cases were trimmed to OAL, had their flash holes deburred, mouths chamfered and primer pockets reamed. Powder charges were measured with a RCBS Charge Master. 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.
I used a Hornady OAL gauge to determine that when the cartridge OAL was set at 2.820″ the SMK was at the lands. I loaded 6 rounds .010″ (A), .050″ (B), .090″ (C), and .130″(D) from the lands (below).
I fired two 3-shot groups of each load at 100 yards.
I started with the loads close to the lands (top left), and end with the load furthest from the lands (bottom right).
Note the group sizes were fairly consistent, with the exception of a called flyer in with the second -.010″ group.
Load A, .010″ from the lands grouped .217″ and .667″. The .667″ was the result of a called flyer.
Load B, .050″ from the lands grouped .264″ and .296″.
Load C, .090″ from the lands grouped .390″ and .251″.
Load D, .130″ from the lands grouped .289″ and .124″.
Looking at the results, I think it would be safe to assume that the 142 grain Sierra MatchKing (SMK) is not particularly sensitive to seating depth.
The upside of shooting 3 shot groups is you save ammunition and barrel life, the downside is they do not paint a picture of accuracy as well as 5, 10 or 20 shot group. In retrospect, I wish I had shot 5 shot groups as they may have exhibited larger differences in OAL. I was still amazed I was able to shoot a group that measured .124″ with the bullet seated over an eighth of an inch from the lands.