This is an interesting thread and there is a great deal of confusion on the subject of McDermott Cues.
From the 1970's until the Mid-1990's McDermott used a weight bolt design that had the bumper secured to it by a screw. The cues that used this design were the MR Series (A), the B-Series, the C-Series, the D-Series, the Wild Life-Series, the HD-Series, the E-A- Series, E-B Series, E-C Series, E-D-Series, E-F- Series, E-G- Series, E-H - Series, E-I -Series, E-J - Series, E-K - Series, and the E-M -Series.
These cues did not use a threaded Tenon that the Butt Cap screwed on to, the weight bolt gave the Butt Cap extra security in case of a Glue failure where the Butt Cap and the Tenon were attached. This in no way means that the cues butt cap would fall off if the weight bolt was removed, however, without some form of weight bolt being in the cue you could not secure the cues bumper and that is what they were talking about concerning the weight bolt.
Since the 1990's McDermott has used a push in bumper design which is not attached in anyway to the weight bolt of their present cues. Now it is not necessary to have any weight bolt in their cues and nothing will happen that will lose parts or damage the cue.
Many cue makers have used a butt cap / bumper design over the years that required a weight bolt for structural integrity, in fact some of the most famous cue makers in the world used this design to name a few George Balabushka, and Gus Szamboti. These gentleman used a material called Delrin for their butt cap material, because they it is very very strong and because the cues butt cap in many cases can be damaged from anger.
The problem with the material is that it's surface doesn't allow adhesives to stick to it very well, so they used the weight bolt not only to secure the bumper, but to also reinforce and hold the cues butt cap in place.
I hope this information helps clear up some of the confusion and that it also helps everyone understand what importance the weight bolt actually plays in the cues design.
Take Care