So, what is it, and why is it controversial?
The basic 1911 design includes a short "half" rod into which the base of the recoil spring is slotted, and a matching "spring plug" into which the tip is slotted:
The spring plug is held in place by the barrel bushing, which also centers the barrel in the slide, allowing for tight lockup and fitting in a part that's easily replaced (instead of having to replace a whole slide when it wears out for example).
It's a pretty ingenious design. It's simple, efficient, works well almost all the time, and people are comfortable with it.
In the 70s, people started introducing a new guide rod design, that used a guide rod extended out to end flush with the barrel and bushing, and a hollow spring plug that acts as a bushing for the rod:
and a shot showing the difference between the standard, and full length rods:
The spring plug engages the barrel bushing in the same was as the standard spring plug does; with the pressure of the spring behind it pressing it firmly into the bushing flange (the little half moon notch in the bottom there):
There's another type of full length guide rod, that uses what's called a "reverse plug". They are usually a telescoping design with a secondary captured spring, and they looks like this:
The reverse plug, instead of engaging the bushing to be retained in the gun, engages the rear of the recoil spring hood (the part the spring plug fits into). This allows this design to be used in guns with a bushingless bull barrel (though reverse plugs are not always, or necessarily used with bushingless barrels). Oh and that little green part is an aid to disassembly, not a part of the gun.
So, what does a full length guide rod do?
At the most basic level, an FLGR allows you to use a much heavier, or much lighter recoil spring than standard, without worrying about a spring kinking or binding (which can be an issue). In theory the guide rod improves consistency in spring operation.
This much is indisputable. The FLGR will do exactly that.
There are a lot of folks who say you don't NEED to worry about spring binding or kinking... and for the most part, in a 5" government model, they're right; unless you are using EXTREMELY heavy, or light, springs.
A well fitted FLGR will also improve the consistency of the gun as a whole, by increasing the rigidity of the gun, and the frame to slide movement.
The FLGR will do exactly that as well.
Unless it is a match fitted gun, the difference will be so small as to be negligible; and in the case of the standard plug style rods, if the rod isn't fitted perfectly (or is allowed to get too dirty) it can actually CAUSE binding and stiction.
Finally, a standard FLGR in a bushinged gun makes disassembly more difficult; generally requiring a tool (usually a straightened paperclip - it fits into the little hole sometimes drilled in the rod as seen in the comparison pic above), either to hold the recoil spring, or to actually disassemble the guide rod itself (some rods are constructed in two or even three pieces, designed to be unscrewed with an allen wrench).
Without such tools or disassembly of the rod, it is difficult to push the recoil spring plug out of the way of the bushing, so that the barrel can be removed.
For all of these reasons; 1911 purists and traditionalist (and there are many, and they are... rabid would I think be the best term) tend to disdain FLGRs; often with a passion far exceeding the bounds of rationality.
Personally, I think they have their place; and in some cases are a great improvement to a gun.
You’ll note, full length guide rods are, and always have been in many other pistols (SIG, Glock, S&W, BHP etc..) it’s not like they are inherently evil or unreliable; and they serve a purpose, if using very light or very heavy recoil springs (especially if the gun in question is chambered in .45 super, 10mm, .460 etc...)
In any 1911 variant shorter than a Commander, they are pretty much a necessity to avoid spring binding with the heavier recoil springs (or double captured springs) required for reliable function. Some officers models don't have them (most do), but in my experience reliability requires them. I don't think I've seen a micro-compact style 1911 without one.
Full length rods (generally of the reverse plug design) are also necessary if using a bushingless bull barrel; because, obviously, there isn't a bushing for the spring plug to seat against.
I have had full length guide rods in guns, and I’ve had GI guide rods. I prefer a properly designed and fitted FLGR with a reverse plug to the GI guide rod; but I prefer GI to all other types of FLGR (especially two piece or three piece designs).
Why's that? Well first I like double captured recoil spring setups for guns that fire .45 super or 10mm; and for shorty 1911s.
Also, unlike solid one piece or two piece FLGRs, the reverse guide rod setups actually make disassembly EASIER. The reverse plug guide rod allows you to slide a 1911 upper of as one piece, and rapidly disassemble it without the danger of parts flying everywhere.
Instead of compressing the recoil spring plus and turning the bushing, catching the plug as it tries to fly out across the room (every 1911 owner has lost at least one), you simply pull the slide stop out, side the upper off, and pull the recoil spring and plug assembly out from the rear; as you do with SIGs, Glocks, BHPs, and most other auto pistols.
Finally, by it’s nature, the reverse plug guide rod is less likely to bind than other FLGR designs; and it less sensitive to fitting. Combined with the advantages of it, I think they are a reasonable improvement to some guns.
I do agree with the purists on one thing though: one piece or two piece standard plug FLGRs are a pain in the butt; and unless I'm shooting 10mm or .45 super, I'd rather not have one at all (or I'd rather have the reverse plug).
Oh, and on a related note, what about recoil buffers?
These are little reinforced polymer squish bushings that fit in between the base of your guide rod, and your slide. The very slightly reduce felt recoil, and in high pressure loadings they can reduce frame battering to a significant degree.
Well, generally speaking I recommend against them in carry guns; not because they don't work (at least for frame battering), but because they can fail; and when they do, they can cause a gun to jam. It's rare, but I have seen it happen a few times.
However, for competition or range guns, especially where thousands and thousands of rounds will be fired through them (and especially in frame battering loads like 9x21, 9x23, 10mm, .45 super, and .460 Rowland) they certainly have their place.
I actually recommend them strongly for 1911s chambered in 10mm (or higher pressure loads), particularly the Colt Delta Elite (which has a nasty tendendy to develop frame cracks); because a slightly loosely fitted 1911 in 10mm will batter the hell out of it's frame, and can crack and peen, reducing (or ending) the life of the gun.
Oh and I say for competition guns, even though they reduce reliability? After all, extreme reliability is critical to winning matches.
Yes, for two reasons. One, it's a VERY small chance of failure if the buffers are replaced as they should be every 5000 rounds (or more frequently for 10mm and above). Match guns are generally maintained to a higher standard that ensure buffers are regularly inspected and replaced.
Two, given the number of rounds fired through competition guns; and the pressure of .38 super, 9x21, and 9x23 loads required to make major, which are frequently used with relatively light recoil springs as compared to a carry gun (and the resultant high slide speeds); the small chance of failure of the buffer is outweighed by the INCREASE in reliability caused by the reduction of frame cracking and peening.
It isn't absolutely necessary to use an FLGR with a recoil buffer; but it is HIGHLY recommended, because a short guide rod can more easily squish the buffer out unevenly, causing it to fail sooner.
Now, against all of this you'll generally hear two arguments from 1911 traditionalists:
1. "John Moses Browning didn't design it that way"
2. "The berm at Gunsite is littered with guide rods"
Both of these are classic appeals to authority. Let me counter them with two more (hey, they are just as valid... in fact more so I'd say):
1. No he didn't; but he did design the Hi-Power with a 3/4 guide rod, so there obviously isn't anything inherently wrong with a longer guide rod, nor did Browning have an objection to them (in fact he thought it was a better system). Almost all handguns based on the browning cam block tilting barrel system (SIG, Glock, HK... really almost everybody) use a full length guide rod.
2. Bill Wilson, Les Baer, Ed Brown, STI, Strayer Voight, Para-Ordnance, S&W performance center, Springfield, and Kimber all build almost all their guns (anything above the most basic models, unless the customer requests otherwise) with guide rods.
... and I'll add a third:
3. There isn't a single major USPSA competitor I know of who doesn't use a full length guide rod.
As I said, reliability and accuracy are critical to winning in these competitions, so they aren't going to choose anything for their guns that compromises either.
Col. Cooper hated guide rods (for various reasons, some good some not, as described above); people taught by Col. Cooper often developed the same attitude (I'm a Gunsite grad, and I didn't; but I wasn't taught by the Col. himself); often with no justification other than the Col. felt that way.
I'm not saying this to say you MUST have a FLGR, or that you must not. It's largely a matter of personal preference, and whether you find field stripping one irritating or not.
The fact is, except in a match gun, a shorty 1911, or a 10mm; you are likely to see no difference in either performance or reliability.
Let me repeat that for you 1911 purists who insist that a guide rod makes a 1911 into a jammomatic... or you tactical obsessed folks who think that no 1911 can be accurate without one:
YOU ARE LIKELY TO SEE NO DIFFERENCE
IN EITHER PERFORMANCE OR RELIABILITY
IN EITHER PERFORMANCE OR RELIABILITY