Quoted:
I think it went like this, top to bottom.
http://i57.photobucket.com/albums/g236/Gutss/Coltboltevolution-1.jpg

Quoted:


Interesting detail in there...the extractor on the first bolt looks like a newer one, while the extractor on the second bolt looks like the one on my 3-digit '01 and MGMike601's low-4-digit rifle.

To answer the OP's question, I agree that thin band came before fat band, and of course "P" marks came before "M P"...but I've been thinking that the extractor lug with the flat/cutoff design (looking at the back side of the lug) probably pre-dated the one with the sloping lug.

Opinions, hive?

Any chance, Guts, that those extractors got inadvertantly switched?

Quoted:


I really couldn't say, I pirated this picture from a post a few years ago, I just assumed it was accurate, I appologize if it isn'.

Quoted:
While I'm thinking about it, this website has chrome bolts.  Or maybe not ?http://www.gunnyssurplus.com/m16-bolt-assemb17.html

Quoted:
After reading this thread and then re-reading The Black Rifle last night, I made a few observations:

Page 85 (image 103) depicts the 601 extractor lug having a squared off rear. The sketch "View showing bolt and shell extractor" depicted under the handguard clearly illustrates the lugs front being angled and the rear squared off. Although there is no date attached to this drawing, I would assume it is one of the early drawings. (I also noticed the illustration "Section C-C" on page 84 top right is inverted???)

Page 35 (image 43) dated 12-4-56 depicts an AR-10 bolt and the extractor lug is squared off in the back.
Page 42 (image 52) depicts an AR-10 with what appears to be a narrow band on the bolt.
Page 89 (image 108) depicts an AR-15 with what appears to be a narrow band on the bolt.
Page 90 (image 109) depicts an AR-15 with what appears to be a narrow band on the bolt.
Page 92 (image 112) depicts an AR-15 with the extractor lug squared off in the back.
Page 96 (image 119) depicts an AR-15 with what appears to be a narrow band on the bolt.

I think it would be safe to assume that these images were all taken in the early stages of the rifles development. With that said, we could reasonably assume the first bolts were narrow band with squared extractor lug based off the original AR-10's design.

As you look further in the book, you'll notice the progression:

Page 129 (image 136) depicts an AR-15 bolt with the extractor lug angled off in the back.
Page 131 (image 137) depicts an AR-15 bolt with what appears to be TWO narrow bands, one forward of the extractor pin and the original one behind the pin??? Anyone ever seen one of these?
Page 225 (image 220) depicts two bolts. Both clearly have extractor lugs angled off in the back and the bottom one shows a single narrow band. The top bolt is not so clear.

By now the book is discussing the "Ten Post-Production Changes" that occurred during contract "508" Nov '63-Jan '66. I could not find any discussion of when the change to the band or extractor occurred but it appears the extractor changes during this period and the band sometime after.

I would suggest OlGunners observation was correct and GUTS's extractor on the "P" marked bolt was changed at some point in its life. It should have a squared off lug.