The primary reason today is the Palma match that requires it along with a 155 gr bullet. The loads are very hot and the barrels are long to keep the bullets velocity over the speed of sound thru 1000 yds.

.308 dia. 155 gr. HPBT Palma MatchKing .308 155 .233 .450 @ 2600 fps and above
.443 between 2600 and 1800

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All guns should be locked up when not in use!