6 Creedmoor advantages:
- Lapua and ADG brass available without forming
- maybe 100 fps more velocity, but seems like less than that depending on accuracy nodes
- large rifle primer possibly better in cold weather
6x47 advantages:
- small rifle primer more tolerant of pressure
- less powder for almost the same velocity
243 advantages:
- pretty much the same performance as the 6 CM
Does either feed better than the other?
What else am I missing? Everything else identical. 7.5 twist barrel, shooting 90-115 grain bullets, throating set for heavies. Use would be killing things in a lightweight platform.
A lot to digest, but I'll give my opinion on why the rounds on the 47 case are my choice.....
Coming from a pure accuracy/Benchrest background, the standard MO for reamers/throating, was to have the bullet's pressure ring sit above the neck/shoulder junction, to keep the bullet above the potential dreaded donut area. I still abide by that principal, so when I order a reamer, I make a dummy round, seating the bullet(s) of choice to that criteria, with regards to OAL in the intended magazine box, to engage the lands .020", give or take. With 99.9% of the time being used in a 2.800" Remington box.
With the 6x47 Lapua having a case length of 1.850", I can have a loaded round of 2.750" OAL using a 105 Berger VLD seated in the lands .020", and still have plenty of room to chase the lands during barrel wear. Feeding has never ever been a problem what so ever. I have had five of them.......
The above applies to the 22 and 6.5 versions on the 47 case as well.
So right out of the gate, the CM case is .070" longer at 1.920", the 243 worse yet at 2.045" case length, meaning the bullets can't be seated to the criteria set above in a 2.800" mag box. If you run detachable bottom metal, this all goes out the door, with their 2.995" OAL capabilities. As does running "normal" FL dies with the expander ball, as that irons out any donuts, and/or pushes them to the outside to not affect seating or neck tension. So then your only worry is not seating the bullets too deep crunching powder, which can push bullets out some.
I've hunted at well below zero temps and never had an issue with SRP's. I do use 7 1/2's for hunting.
Lastly, the 47 gives up little to the bigger cases, and certainly has no question about it's accuracy.
