[SteelyDan]

Dumb question, I figured it out. Sorry.

[geekWithA.45]

I'm gonna reply anyway, in the the public interest, because if you screw it up, the rifle WILL explode.

1) Insert lubricated bolt into carrier, orient extractor to about 7 oclock, and ejector to about 1 oclock.
2) Insert lubricated CAM PIN into bolt through hole in top right of carrier. (If the cam pin is missing the rifle not might not can but WILL explode upon firing) It should only fit 1 way.
3) Insert lubricated firing pin through rear, push all the way forward
4) Insert firing pin retaining pin into carrier from right side, ensure that it actually retains the firing pin.
5) Inspect gas key for tightness, use hex driver if needed.

[BigG]

4) Insert firing pin retaining pin into carrier from right side, ensure that it actually retains the firing pin.

If we take this in the conventional sense of rifle held as if being fired the instruction is bassackwards: s/b insert pin from the left side. There is a countersunk recess for the cotter pin head in the L side of bolt carrier.

Not trying to be a smart@$$. :)

[geekWithA.45]

I see your point, and in fact I almost wrote it the way you suggested, but I was trying to be consistent with the o'clock instructions in step 1, and the described location of the cam pin hole in step 2, which presumes the bolt and carrier is oriented facing towards you.

I'm pretty sure rule 2 doesn't apply to ar-15 bolt carriers sub assemblies, so I had no fear of looking my bolt carrier in the face. ;)

No biggie, either way.

[BigG]

I guess it comes from being consistent when talking about how to fix something. The driver's side of the car is the left side as if you are sitting in it, not standing in front of it looking at it. Same with firearms, as if you have it in your hand. The hole in the left side of the carrier keeps the cotter pin captive. If the pin was on the right side, it would probably come out thru the ejection port.

[Fudgie Ghost]

And don't forget to stagger the "gap" in the three gas rings!