Thanks , I have talked to some people and they agree with you that this is not a good idea.Not to be a 'stick-in-the-mud'... be careful with subs out of a 16" 300BO... We have had a 220gr 'stop' about 2" from the muzzle... YMMV and all that... Could have been a light charge...
180 gn out to 100 yards...why not 308? If it is to mate to an existing lower, 6.5 Grendel. 300 bo seems like the wrong tool for the job. Now if you're not hung up on 180 gn boolits, 110 -125 would be great.