I'd buy a heavy barrel SPS Varmint in .243. Shoot 105 Amax's in it and be done. I have one I ran a .243AI reamer in that will shoot 5 shots in 1/2". I put a brake on it so I can watch the bullet impact and the recoil is literally like a .22lr. Even if you punch it to .243AI factory .243Win. ammo will still work through it.