Haven't read all of this thread.
I have no doubt 223 can effectively kill fallow. Often used in other states. But I wouldn't use mine on a mature buck. Doe, yes, but not legal here anyway.
Have shot fallow, but mainly hunt sambar. A few weeks ago took an off hand shot at a small sambar, about 30 yards. Not big, about goat size. Side on 30.06 180gr interlok. Entry slightly behind R shoulder. Exit, L shoulder, smashed. Big exit hole. I mean, about 50mm dia. (I remove the tips of those bullets)
She ran about 50 yards up a gentle slope, jumped an old fence, did a big U turn and fell over. All up about 70 yards. When I found her 5 minutes later still alive so, shot again in the head.
Shot fallow buck last year, 30.06 130gr bullet, 2900fps, 100 yards.
Same placement. Exit L shoulder. Ran about 60 yards. DOA.
A bit bigger is always better IMHO.
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