i got a bag of parts from a friend but some of the pin hole sizes ( like the hammer) are different than what i got, can they be drilled to fit or are they junk? most seem to be smaller than mine.

Welcome to the board Chief!

It sounds like you have a Colt with .170" hammer and trigger pins. Is this correct? Standard sized pins are .155" (I think). I haven't measured my small pin ARs.

Personally I wouldn't mess around with drilling since these parts are hardened blah blah blah.

Large pin Colt fire control parts can be purchased anywhere, even Bushmaster sells them [url=http://www.bushmaster.com/shopping/lowers/arcoltkit.asp]here[/url]

I've been having pretty good luck finding them on eBay for a substantial discount. Recently I found a brand new set of Colt FCG parts for $19.95.

Edited to add: I'd hang on to them in case you ever buy an AR they are compatible with [:)]

[url]http://www.biggerhammer.net/ar15/pins.html[/url]

Chief, you may want to make sure those parts aren't automatic parts too.

Auto[img]http://photos.ar15.com/ImageGallery/Attachments/DownloadAttach.asp?iImageUnq=19406[/img]

Semi[img]http://photos.ar15.com/ImageGallery/Attachments/DownloadAttach.asp?iImageUnq=19427[/img]

A better pic, thanks BFI.
[img]http://photos.ar15.com/WS_Content/ImageGallery/Attachments/DownloadAttach.asp?sAccountUnq=12467&iGalleryUnq=1145&iImageUnq=22116[/img]

Notice the difference in the selectors, hammers and discos. The diff in the trigger is more difficult to see. In an auto trigger the slot the disco rides in goes through the rear of the part. Semi triggers are solid at the rear.



[gramma][new pic]

yep its a colt and the pins are .17, a couple of the pieces i got are auto so junk for me, the rest are s/a by looking at the pics.
so do i understand it right, colts are big pin and the rest are small .15 pins ?

Some Colts are, some aren't. The early ones are .155".

0.1560" + 0.0015" for the pin holes.