Just wanted to report on last night's fiasco with the Bushmaster Pivot Pin Tool. I had heard that installing the pivot pin spring, detent and pivot pin was a bear, so I ordered the magic tool from Bushmaster. Let me tell you, it was still a pain in the derriere. I spent over an hour wrestling with the parts, carefully pressing the spring and detent pin and attempting to push the tool out with the pivot pin, as the instructions said. After the first ten tries or so, things settled down, and the pivot pin detent was giving me nice sub-moa groups on the kitchen ceiling. SPROINNNG! reload. SPRROINNNNG! reload. SPRROINNNNG! reload. Finally, I gave up, went to bed and bright and early the next morning visited my local smith. "Happens all the time" he said. "Whatcha do, is cut a loop or two off the spring. Then it slides right in." And sure enough, it did. But there's still plenty of upward pressure to hold the pin in place.

In my humble opinion, the Bushy tool isn't worth the money. It's very soft, and when I turned it to hold down the detent, it deformed badly. And when it's rough, it doesn't slide out smoothly, which means the pivot pin is even harder to get into the hole. I had to file and sand the tool smooth about four times during the whole process, just to keep it "working". I do think having the pin held down is a good thing, and I saw another, home-made tool on one of the boards here, and it looked like a better setup anyway. So, that's my two cent's worth. I just had to vent. Hope the rest of the assembly is easier. If it isn't I'll be too old to shoot by the time I get it all together.

I built my own by cross drilling a brass punch.It works very well and I can install a pivot pin in seconds. I have however noticed some inconsistency in the springs and some do in fact seem to suffer from coil bind. I also had one detent that was considerably over length and required shortening the OAL. I've not used the BM tool but will say that a shitty tool is sometimes worse than no tool at all.

I have the Bushmaster tool and like it. It also serves to push stubborn pins out without marking the ends.

Seems to me you should bitch about the out of spec springs.

I used the pivot pin tool from Bushmaster and the spring did jump out twice, but I got it the third time. I thought the tool was well made, it does its job and pushes the take down pins out easy. The hardest thing was putting the roll pin in for the bolt release!!!

I've got the Brownell's...it's very solid, smooth as a baby's bottom too.  The first time I used it, I did the whole thing in about 15 seconds.  The second time took me several minutes; I ended up having to cut a couple of coils off.  This was the model 1 kit, and if memory serves me, I had to cut a couple of coils off the rear spring as well.  

I think it is a fantastic tool.  I've installed the front detent and springs many times in just seconds.  It also doubles as a pivot pin removal tool for my FAL's.

A delrin punch like the ones DPMS sells would also work like a charm with a cross hole drilled, plus they work great for pushing out pins as designed. Very cheap.

Before installing any springs and detents in any long thin holes or slots, it helps to make sure the holes are clear of manufacturing debris and/or finishing smut. I use a drill bit and turn it by hand to remove any debris.

My poor man's takedown pin tool, which is available at any hardware store, is a 35 to 50 cent clevis pin of slightly smaller diameter than the takedown pin, a feeler gauge, and any long thin tool that will fit in the clevis pin holes.
Basically stick the clevis pin in, line up one of the holes, drop in the spring and detent, put thin tool in the hole and depress detent. While you've got the thin tool in, depress detent as far down as it will go just to make sure it goes down far enough (not binding or stacking). After checking that, rotate clevis pin to hold the assembly in and remove thin tool. Slide feeler gauge between detent and clevis pin (this is the hardest part, but not hard). Push down on feeler gauge and hold it in position while removing clevis pin and installing takedown pin. Pull out feeler gauge and it's done. Takes a lot longer to explain than to do. You might find it easier to slide in the feeler gauge if you taper one side to an edge, makes it easier to get it between the detent and the pin.

Funny you should mention that about the feeler gauge. That was my next gambit, but my son borrowed mine and hasn't brought it back. Oh well, all's well that ends well. I mainly posted to let everybody know about the spring possibly being too long, and to check that as a possible solution to difficult installations. Never meant to bash Bushmaster.

I use the tool Legal Transfers sells, and it is amazing, I was able to install the pin on my very first try, didnt see why someone would try to do it without the tool.

I built a new lower this past weekend.  This is my second build and second time I used the razor-blade trick.  Not a problem in the least.  I have more problems with the bolt-release roll-pin.

Old trick, with spring and detent installed rotate pin 90 degress, press down lightly and straight, insert pin then rotate back once pin in about halfway. In the field there are no tools other than a dummy shell and a dental pick.

stormbringer66, well said.  And welcome!