I shoot .223 Speer 45gr. bullets on ground squirrels out of a Hart(.224) barreled 223Rem. Those bullets group in the .4s &.5s. Pedro

It does not make that much difference.
I shoot a .224 46gr Hornet type bullet with a blunt nose out of a .222 bore.
Caliber 218 Mashburn Bee and those give me the best performance.
3 different aspects ranging from .222 to .223 to .224.
Go figure huh?

-Spencer

Hey craigster, I had a few M43 Winchesters and they all had the 0.223" barrels. I could shoot the 0.224" Bullets in them, but they just were not quite as accurate. I'd not argue with anyone that said they saw the exact opposite though, just depends on the barrel.

All the 22Hornets I wrestled with, including those with 0.224" barrels, were "before" the new really light bullets and Lil'Gun Powder, so all my experience is old and dated.

Best 0.223" Bullets I used were the 45gr Sierras, but I don't know who even makes that size anymore.

Possibly, maybe, could be, that since Hornet bullets have very thin jackets and may be swaged slightly or might even obturate a bit, it probably doesn't matter a toot.

PO Ackley did some testing on the use of oversize bullets and found that some very large bullets would find their way down a barrel now and then with no observable damage. IIRC he started this after trying to use same in 'test to failure' scenarios. Don't try this at home BTW.