Well....all things considered here.....I still like the M9, and think it to be one of the best knives ever.
That is the Phrobis version, as the more recent variety is a bit different.
As for the handle, one must consider that Armies are made up of people of all different shapes and sizes.
So many inventions intended for the military must be adaptable to hands of all sizes etc.
They also must be handy in all different lighting, wet, dry, or frozen environments with or without gloves etc etc.
So, the M9 handle although not the most comfortable is the most versatile IMO
As for the name Bayonet ...well I think the idea
changed to knife primary, spear secondary.
Yes in days of old spears were a more effective weapon than firearms that may not even function, and fired one shot etc.
But those days are long gone Certainly many might agree than in a situation were
a firearm is rendered useless by mechanical difficulties, or no ammunition, a person armed with a rifle with fixed bayonet may be better off than the guy with a pocket knife.
Finally, the Original Phrobis version of the M9 was forged, and allowed the knife to be tempered for flexibility, yet retaining a good amount of edge holding ability....something many older bayonets lacked.
This added with the serrations intended to saw through downed air craft bodies, make it a doubly handy tool.
Of course everyone will not agree, and one of the major drawbacks to the whole M9 family IMO is the over built rather bulky sheath, which could use serious improvement.
Further, the modern M9 Bayonet was changed by contractors, to increase their profit. This was done within the Gov spec's, but removed many of the greatest features of the Phrobis rendering it heavier, and IMO less.
As for the C.U.K. on the 11.5" M4.....well, I would not choose the 11.5" M4 unless I were using it in close quarters.....so,a shorter knife to attatch to it may be warranted for urban situations.....even though in use it may be less effective impalement,with a 5.5 inch blade than a 7.5 inch blade. The extra 2" may not reduce the impalement effect, as much as it might reduce the chances of the user ever getting to that point if the 2" were protruding out of a corner allowing the adversary to deflect the knife and rifle for long enough to use what ever means he or she might to end the conflict..
Finally, one cannot fully appreciate the concept, without first
closely examining the Phrobis C.U.K.
The knife is based on the M9, but there are several improvements one Great big one being the sheath.
It is so much lighter and easier to attach and use in a wide variety of situations, and the knife is handier lighter and IMO more usable for many tasks, yet still super strong with the application of lateral loads etc as the knife is forged with the fuller in place etc.
So, it sort of shifts the balance and makes the primary task be knife and secondary task be spear.
I think the Russians did this on the Ak quite a few years ago.They offered a spike, but later a smaller detachable knife.
So I like the invention, but think it would be better if the C.U.K.
were the base