Thinking about getting a 284 win. barrel for my encore. I had a 284 years ago and still have the dies. What would be the best length and twist? Would be used mainly for deer,maybe black bear.

Intended ranges? Location of hunting?

For me, considering the locale here, I'd go with a 20" heavy contour; short (really short on the Encore frame) enough for treestands and stalking around, but heavy enough and with enough velocity for long-range when asked of it.

Of course, if you're gonna be doing some long-range stuff, a 24" or 26" might be more applicable.

IMHO, with that round, anywhere between 20" and 26" works just fine and would get dictated more by use and terrain than by ballistics.

284, rebated rim, no good in Encores. Extraction is slow and clumsy at best. Rimmed cartridges are best of course, 308/30/06 family works ok to.