W. H.'s 6mm Creedmoor RPR Tack Driver
Everyone and their brother has jumped on the 6.5 Creedmoor bandwagon. If you listen close enough to the long range chatter, plenty of folks are whispering about the 6mm's making a comeback. The 6mm BR and the Dasher are both making their way into the non-benchrest competition world. These cartridges had been relegated to the single shot world but now there are multiple companies making adapter kits for the AICS magazines and folks have been making do with custom BDL fixes. Now you can't go to a PRS match without seeing all of these.
Now comes the 6mm Creedmoor on the scene. Those who have been arguing about the Dasher versus the venerable 243 Win may want to throw their hands up in the air at yet another challenger. I happen to like the 6mm Creedmoor for numerous reasons.
The first stone people hurl at the 6mm CM is the availability of brass. To this I say get over it. Lapua sells small primer pocket 6.5 Creedmoor which necks down quite easily and unless you're running a tight neck or min-neck, you won't have to worry about turning. For this project I used a Whidden full length die and had no trouble taking virgin Lapua down to size.
The next complaint is that the 6mm CM doesn't do anything the already established 243 Winchester does. That's not completely true. Even if the Creedmoor wasn't slight faster the 30 degree shoulder is inherently more efficient and achieves these velocity with less powder. Less powder equals less recoil and longer barrel life. End of story.
Now there have been reports of feeding issues with open tipped match bullets in AR-10 platforms in both 6.5mm and 6mm Creedmoors. This happens with every new cartridge. Feeding problems can be frustrating but the response you'll get from most industry veterans is to get off the couch, grab some sandpaper and a feed lip tool, build a bridge and then get over it.
I find the Ruger Precision Rifles to be very frustrating. Frustrating because so many of them shoot so well. Fortunately for the custom rifle world they only appeal to the entry level crowd and with hammer forged chrome-moly barrels stress and fouling issues will lead end-users to want to upgrade. That being said, I have shot some humdingers this year and W. H.'s 6mm CM was frustratingly easy to shoot and load developed easier than teaching my dogs to eat bacon.
As described above, I resized some new Lapua 6.5 CM small primer brass and sent it through a new 6mm CM FL die from John over at Whidden Gunworks. It's worth the extra effort to lube these case generously and I even set OneShot aside and use Imperial Wax on the outside of the necks to avoid scratching the near-overly soft, annealed cases. The cases chamber easily and a quick measurement of fired factory brass told me these necked down cases would have enough clearance in the chambers neck area. These case were then tumbled in walnut media to kick off the majority of the lube.
I went with CCI 450 primers because of their known performance in my 6.5x47's and tried some Reloader 16 for some optimal charge testing. I quickly settled on 41.0gr even behind a 105gr Berger OTM Hybrid. The results were exception. (See Picture!!!)
Upon further testing the load would occassionally throw a round out of the group. A quick change of seating depth solved this without much effort either!
The final verdict? Other than the 6mm SLR, the 6mm Creedmoor should probably be on our list as our next 6mm.