I have one on a 338 Win Mag that I just sold to a friend. Rem 700 and it came from the factory.It is removeable by threading off (left hand threads). IMO I am very glad it is removable! While it was nice while shooting at the bench, the first time I fired it hunting was enough. I bought the cap that protects the threaded end of the barrel and took it off. Too much noise for me. Just my opinion! FWIW, my newest 338 does not have one nor will I add one.

There's 2 dates they carve on your tombstone.
Everyone knows what they mean.
What's more important is time that is known
as the little dash inbetween.

Razz