I just picked up a savage 340 hornet. Been in the market for one for a while and this one showed up at just the right price. My question is I see bullets marked as .223 hornet but I also see people loading .224 pills. Does it make that much difference? I've read here they can be picky. I was thinking of running some factory stuff this weekend just to get some brass for starters.

I believe the Savage 340 didn't come around until after the time when the standard Hornet bullet diameter was changed to .224 so that's where I'd start.

Should be 224 since that model was introduced in 1950. Heres some info, and a page link

"Savage 340: The mother company, Savage, picked up the design the same year, (1950) & produced it under the renamed model of 340 which remained in production until 1985. The Savage 340, was basically the same gun as the 325 but with modernizations & with caliber variations. The bolt handle was changed to the more common round knob type. The stock was changed to walnut & was modernized somewhat toward the latter production years. Pressed checkering was on some later models. Regular dovetailed type rear sights were used. As far as we can tell all the 340s were factory drilled & tapped for a side mount scope base Weaver #1). Savage also made a stamped out sheet-metal scope base/mount for this model."

http://www.wisnersinc.com/additional_info/Savage_340.htm

I shoot both .223 and .224 in mine. I think you will find the type or make of bullet will affect your groups more than the .001 inch difference.