What sort of bullet do I need to use in my .243 to get the penetration needed to achieve a clean kill?
Sika deer are a fraction lighter than Fallow on average and a little shorter at the shoulder, so we are not talking about heavy, thick-skinned game.
Sika are reportedly tougher than Fallow and I know a lot of stalkers who are not too happy using a .243 on Fallow bucks so it?s important to place the bullet accurately and, as you suggest, choose a bullet of suitably robust construction.
My first suggestion would be to consider up-grading to a 6.5×55, a 7mm-08 or a .308 but if you are happy with your .243 and confident with it, then ammunition loaded with bullets of 100 or 105 grains should do the business for you.
I used to get good results with Speer?s 105-grain round nose but that is no longer available.
However, their 105-grain Spitzer is still available or, if you feel you need even more strength, their 100-grain Grand Slam.
Other manufacturers offer similar bullets and there is also a raft of expensive premium jobbies which can sometimes be found in ready-loaded ammunition.
The best bet is to see what you fancy and try it to see if it works for you.
We are all different, which is why there are so many different things available.
Or you could decide to do the job like a gentleman and invest in a .308?