How is the M-14 not modular?
The trigger group is interchangable, as is the operating rod and bolt (to a degree)
That's not modular. Modular is changing your caliber, barrel length, sights, and even operating system in under a minute. However, modularity is not the issue here. Ease of maintenance is. An AR can be built from the ground up in about an hour with an armorer's wrench, a vise, and a set of headspace gauges. (That's not an exaggeration.) Any other work is only easier and quicker.
I would not personally attempt to build an M14 at all, even if I had the tools to do it.
More to the point, things just plain go wrong less frequently with the M16. I've only personally dealt with two that were deadlined for good that I can remember -- one kB! and one dropped into the bottom of a drydock. (I saw a few go out of service due to overenthusiastic automatic fire but they could've been restored to service fairly easily, although I wouldn't expect them to group well afterwards.) I also saw several more OOC rifles at the Ft. Lewis DRMO, all of which were quite visibly trashed; one in particular looked as if it had been run over by a tracked vehicle. I didn't get a confirmation on that but those folks at Lewis certainly know how to have a good time.
I've seen enough faulty M14's that I can offer points about the frequency with which certain things go bad, why they go bad, and possible solutions. Hence, my point to John about the front sights; while the blade is protected by ears, the entire assembly itself is secured by one rather small dovetail and a tiny hex head screw and is not protected. Any blows to the ears won't affect the blade but they
will dislodge the mount, throwing your windage off at the very least and probably stripping the screw out at the same time. Note that a spare screw is not included with the rifle, nor does the combi tool feature a driver for it.
Result? I've got to track down a replacement and a hex wrench. It's not too bad if it happens in my garage, but anywhere else...
Even if they arrived from the depot with the windage set and the sight mounted properly (these are not givens, BTW) and myself or someone else has taken the time to confirm the windage and scribe witness marks on the sight and dovetail so that the setting can be restored when someone invariably knocks it out of alignment, there's no guarantee that it will stay where it is when the barrel heats up. When I sighted in my own M1A I resolved the situation by star-torquing the damned screw, Loctiting everything, scribing the marks, peening the mount and screw, and praying. It's only come loose once since then. The best part about it is that if I didn't take the time to check the witness marks before shooting, I won't even know things are hosed until I fire it.
I love surprises, but not like this.
If anyone thinks that the front sight is not particularly exposed to damage, I invite them to take their rifle and run around in full gear indoors or enter and exit vehicles. Do so in a hurry under the influence of an adrenaline dump. If that doesn't do the job, drop it. Another approach is to simply box it up and ship it somewhere. Report back, and consult the instructions above to fix things. If you got the rear sight too you're out of luck, as there are no quick fixes for when
those go wonky -- you'll just have to replace more parts.
We have not even addressed the operating rod, stock, recoil spring guide rod, recoil spring itself, rear sight in detail (oh, that rear sight), and the flash suppressor -- any of which can trash the weapon's accuracy and/or zero fairly easily and with no obvious evidence. In fact, sometimes they arrive like that.
Hot-swapping bolts is never a good thing to be doing casually, but I'd be particularly careful about it with a Garand or M14. If the tolerances and heat treat are good the action will be amazingly strong but it's best not to take such things for granted. The same goes for the op rod, as the interface between the bolt roller, op rod, and receiver all affect the bolt's lockup.
As I've said, I still like mine but I make no bones about what it is -- the best rifle of WWII. It was obsolete for its designed purpose before it was built. The fact that it still soldiers on in very limited roles speaks more for the ingenuity of the military than the utility of the rifle.
"This is what they gave us, so let's make it work..."
If the object of maintenance is simply to keep it working, that's rather easy. It's a reliable rifle and reliability is easy to design in -- use a robust operating system that imparts plenty of energy to the reciprocating components and make those components heavy. That's how Garand did it, that's how Kalashnikov did it, that's how everyone does it. Keeping it working
and hitting where you point it at is the real trick.
As a military rifle it was an abject failure. As a civilian rifle, it's not bad at all. It's important to make the distinction in this case. That's why I say that I like mine, but I hated working with them.