I have had three, a rem 700, a model 7, and now a sako L46,
Neither of the Remington were anything special, in fact terrible would be closer to the truth. But the Sako is, This is by far my most accurate rifle, 25gr v-max and benchmark. Consistent, fingernail sized, five shot groups.
I sold my factory ammo off, and reload,
Bought both Remington and lapua .221 brass, what ever I could get, and resize down, via a 20vartarg die, as elk said above.
When I bought the sako, it came with a bunch of .223 brass, that was cut and resized, most of it is gone now, accuracy wasn't very good, and lots of neck splits. Probley need annealing, and retriming.
I have a 700 odd .222 brass I can rework/resize if need be.
I took it back to New Zealand, had it threaded, bought a suppressor, and have had a lot of fun with it the last 6 months, a few goats, one deer and quite a few rabbits and hare's have fallen victim.
I use 25gr HP point for bigger game. gives