Comparing 165 and 180 grain bullets of the same construction, the 180 grainer will penetrate deeper. Big news flash, eh? When using bullets of 'standard' jacketed lead core construction, I prefer the 180 grainer.
My wife and I both shot deer last year with 165 grain Speer Hot-Cors, both from rifles chambered in 308 Win. Neither exited. Yes, both deer died (ho-hum). In 180 grain weight, this make/model of bullet has never failed to exit deer from any of my 30-06s.
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