Ammo is generally more $$, but you can order online (for now) and you can also get rounds that are not loaded to the redline for HD/SD. I always thought the Winchester Silvertip 175 grain load was a keeper.
But unless you hunt, or also use it for a woods carry gun, I'd just stay with the 45 auto.
My G21sf goes from 45 auto to 45 Super in about one minute with a barrel and recoil guide rod spring switch. Now 45 Super is mostly a handload affair, or specialty buy from Buffalo Bore, so it's more expensive, generally, than 10mm... but I like the fact that I can use the 21sf for HD with the stock barrel/recoil spring and my Federal 230 grain HST's, and then swtich it out to 45 Super handloads with a 265 grain WFNGC slug for a hike in the woods or a fishing trip up the Clackamas river.
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