Guide Rod You can choose several different kinds of full length guide rods. In (Fig 1) I show the three different guide rods I know about. The one on the left in (Fig 1) is a stock mil-spec guide rod, the middle one is a two-piece guide rod and the one on the right is a one piece full length guide rod. Now that you have seen the three different guide rods, lets move on to the guide rod plugs. There are several different guide rod plugs (GRP) available. In (Fig 2) you will see all four available. The one on the left is a standard guide rod plug, then second from the left is a open GRP. The Last two are captured GRP. Well now that you see what kind of flavors the guide rods and plugs come in, let's talk about the differences between them. There is a lot of controversy on whether or not the full length guide rod is necessary on a 1911, most people either love them or hate them. Many like a full length guide rod, because it is supposed to make cycling more reliable by not allowing the recoil spring to bind in compression, and compress evenly. Many even say it will allow the recoil spring to last longer. Anyway if you decide to go the full length guide rod route you will have to decide on a one- or two-piece. If you desire a full length guide rod and your pistol has a barrel bushing, IE no bull barrel, your best bet would be to get a one piece guide rod, which will come with an open GRP. This setup will drop in most all pistols with a barrel bushing; the only problem is a plastic barrel bushing wrench will be needed for disassembly of your pistol. The second thing you could do is get the two-piece guide rod and unscrew the last half before taking down your pistol, which makes dissasembly much easier. I personally have had bad luck with the two piece coming apart at the range, so I discourage the two-piece rods. If you decide to go the two-piece route, get some teflon plumber's tape and wrap threads before assembly. The setup for a bull barrel is a full length guide rod with a reverse recoil guide rod plug. Now if you decide to go with the reverse recoil guide rod plug, you will need to modify your slide in one of two ways, depending on which plug you decide to use. The reverse GRP plugs are captured from behind the GRP tunnel on the slide not by the barrel bushing, these are usually used on bull barrel pistols. There are two different styles of reverse recoil GRP's available; one is the STI-SV standard one which is the second from the right or the standard one which is furthest on the right in (Fig-2). Whichever you use your pistol will have to be modified to use them. If you have a hi-cap STI or SV Infinity the slide will probably already be releived to accept the sti-sv reverse recoil plug if you desire to use it. In (Fig 3) and (Fig 4) you can see a pic. of a slide that is relieved to accept the standard reverse recoil guide rod plug .