Advice comes in two main flavours on internet forums
@Shroughaun, advice based on direct experience and advice based on what someone has read elsewhere.
Firstly, 300-350m is the top end of the .243 Winchester’s effective range for regular deer species, which you recognise so that’s all good. Depends which deers species you’re talking about obviously. We say “deer” when in fact the various species range from a spaniel sized animal, to an animal weighing up to say 220-240kg.
Secondly the 6.5 Creedmoor with a 140-150gr bullet delivers a
significant increase over the 100gr (or lighter) .243 bullet at 300-350m. So ignore comments like “slight increase in punch” above, as it’s just not true. The long for calibre, high BC bullets available today in 6.5mm retain their velocity and energy far more efficiently than the traditional 6mm bullets that can be used in 10” twist barrels. You can consult any of the online ballistic calculators to work this out for yourself, always a good idea.
At 350m I’m bowling full sized, heavy red deer with the Creedmoor as if they were built from papier-mâché. The 143gr ELD-X is close to the perfect bullet, ideal for that kind of range. My sample set to base this comment on is around 500 animals now, from red stags through red yearlings, fallow, feral goats and a dozen or so heavy pigs. I recently started filming what we do here, because I am aware that interweb forum claims are hard to validate... and often scoffed at. I was getting a bit fed up with blokes trotting out the cynical anti-Creedmoor sentiment like “new fangled” and so on.
Nothing wrong with a .270, 7mm08, .308, whatever takes your fancy, but you’ve asked specifically about the 6.5 CM. For someone like me, who actually uses one in the field weekly (or daily, for weeks on end), it can be a wee bit tiresome being told by those that don’t use one, that they know better.
So in summary, the advantages of the 6.5CM at your 300-350m ranges are:
- Significant increase in terminal performance over the .243 due to bullet weight, BC and resultant retained energy, in the order of +50-60%
- Improved penetration, due to the heavier 6.5mm’s sectional density advantage
- Much lower recoil and muzzle blast than a long action cartridge like the .270 Win
- A wide selection of excellent factory hunting ammunition
I’ll use the .243 Win all day long sub-300m on our smaller reds and fallow, and definitely goats, and on occasion if circumstances allow I might push it a little further. But in the past several months, I’ve looked at twist rates and BC and determined that at longer ranges, my 6mm shooting is better served by the 6mm Creedmoor. So the .243 Win comes out when I’m expecting to run into animals in the 50-250m kind of range. To be bluntly honest, as a fierce advocate of the .243 Win in the face of all sorts of (usually uninformed) BS, the fact is for the long shots, it’s been superseded by better 6mm cartridges.
The Creedmoor in action... It’s the perfect cartridge for your application.