Re: Wanting a Varmint rifle
.223, .22-250, .243, .25-06, 6.5 Grendel, etc. will all kill varmints. All of these are excellent choices.
Here's the catch:
If the bullet doesn't hit the varmint, your hunting won't be very successful!
How bad is the wind where you are going to use this rifle? If the wind has been known to be even moderately bad at times, scratch all the .22's off the list!
The ultra high ballistic coefficients of .243, and 6.5 Grendel projectiles is the factor you need to consider.
From personal experience I can tell you that the 6mm 105-117 grain projectiles laugh at cross winds. I have shot the .243, the 6mmXC and the 6-6.5x47 Lapua cartridges loaded with these bullets and watched them run circles around the .223, the .22-250 and all .30 caliber cartridges <span style="font-weight: bold">when shooting in high cross winds!</span>
If I was choosing and I needed to have factory ammo, I'd buy a .243. Easy to find ammo that will nail any varmint out there.
If I was handloading I'd have a 6-6.5x47 Lapua built. Having a 6-6.5x47 Lapua rifle "built" can me as simple as having a 6mm barrel re-chambered for the 6-6.5x47 Lapua cartridge. By far, the best brass I have seen on the market plus a handloaders dream!
6-6.5x47 Lapua Uses 7 grains less of powder to get the same ballistics as the .243. That equates to much longer barrel life and better long term accuracy.
I sure miss having one of those ...