I am shooting 2 Boyd's stock, one is an At-One Thumbhole the other is a Spikecamp both chambered in 223Rem.. Both have been glass bedded and neither have pillars. Both are also capable of holding under 1/2MOA out to 300yds.
Yes the rear pillar needs to be relieved to provide clearance for the sear. Also if the rifle used a DBM it doesn't leave a lot of material around the rear action screw hole to be removed to place that pillar.
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