I have recently completed two DPMS lowers. One with a DPMS parts kit and the other with  a Model 1 Sales kit. Everything works the way it's supposed to with the DPMS kit. After installing the pivot pin detent on the Model 1 kit I closed the pin and now I can't move it at all. I tried a delrin punch and a hammer and it's still not moving. Is there any other way to move the detent to slide the pin out so I can install the upper half? My next step is dremmeling. Before installing this detent I noticed that it had more of a point than the others.

Terry;
The pointy end was supposed to go into the spring.

I would just keep whanging on it. Sooner or later you are going to round over that point and it will work. I don't see how you can damage anything. Grinding on something would be pretty drastic.

Of course, a whole bunch of guys may come out of the woodwork and say I am crazy.

Good luck, I think it is just a minor thing.

Cheers!
Him

On the DPMS kit both ends were blunted points. On the Model 1 kit the other end was flat.

I did the same thing with an 80% build I did.  The Front take down pin got stuck so I banged on it and ended up breaking the detent out the side of the receiver.  I ended up using a 1/4 inch bolt and nut after grinding the ridge away.  SO unless that is what you want to have to do, be very careful.

Get a curved sailmakers needle (or upholstery needle) and run the point of the needle in the grove of the pin (between receiver ears) to depresss the detent pin.  Look in the back of the TM to see how this is done.  They even tell you how to make a proper tool for disassembly of the pin

Cut the pivot pin and pull it out the same way it entered ...then buy a new one u dont wanna mess up that lower...

I think I elongated the detent hole maybe .015" by whacking on the pin. At least I didn't blow out the side of the receiver. I have ordered a set of dental picks hopefully one will work. If that doesn't do the job then it's drill press time.

Hi Terry,
 Don't worry too much if the hole is only .015 out of shape.It really shouldn't be a big problem.
  Do you have a Dremel Tool?If you do or have access to one,try using a thin abrasive cutoff wheel to cut into the head of the pin from the side(right beside and as close as possible to and paralell to the flat).This should cut into the retaining pin and enable you to release it.Of course the pin will be ruined but it beats damaging the lower.
  If you need a pic,I'll borrow a digital camera and learn how to post it here!

Good luck,Robert.
Edited to add:
If you don't have a Moto tool,you could center punch the head of the pivot pin and drill the head off with a 15/64" bit.This will drill the head off with out drilling into the reciever if you drill dead in the center of the pin.If it wanders to one side,use a smaller bit.After you get past the head,a pair of pliers may twist the head off of the pin body.Any slight damage to the reciever will be hidden by the replacemant pins head.
Robert.
 

Do NOT use those thin abrasive wheels in the Dremel kit for this.  They will explode with the slightest side pressure.

They make a special mandril and a fiber reinforced cut off wheel for things like this.  You can find this in the tool section at Walmart, Home Depot, hobby shops.

Wear safety glasses!!!

Wear safety glasses!!!

Wear safety glasses!!!

Cut the pin right in the middle and press it out.

The dental probe worked! There was one in the set that was the perfect shape and size to depress the detent. Thank God I didn't put the upper on first. I am reshaping the detent to be more rounded. The recess in the pivot pin looks like it might be a little too deep and not beveled enough. I'm not sure if I should get a new pivot pin. I know they are only about $3 but I'm getting a little impatient to get this thing together.

Well kudos there TerryR.While it was only a three dollar part you saved,it's good practice for when you have a problem with something more expensive.
As for reusing the old one,maybe tomorrow morning you should order a new one and if it doesn't get there by the end of the week then think about reusing the old one.
Robert.

TerryR

I did the exact same thing a half hour ago. Where did you get your dental tools at?

Brownells also sells a tool for doing just this

[url=http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=432&s=1987#1987]PIVOT PIN DETENT DEPRESSOR[/url]

Edit: Hmmm.  I actually have one of these and I took a close look at it.  It's nothing more than a thin (don't know what size) allen wrench with the short end ground to a very thin fine angle.

The dental picks were purchased from Widget Supply (I think that's what they are called) About $8 with shipping. I reshaped the detent but the pivot pin still keeps getting stuck. the holes are definately too deep. I ordered a new pivot pin this morning and also a couple of extra detents. I'm staying away from Model 1 Sales from now on. There were at least three defective parts in the lower parts kit that I got from them.

You might also try shortening the detent spring.  Some of the drilled holes are short in some of the lowers I have seen.  If more than a couple of coils hang out of the hole, this may be what is binding you up.

It doesn't take much spring pressure for that detent to work...