AR15 bolt wear points and rebuild

[alpha_romeo_XV]

Interesting to see where all the wear is. The bolt shoulder looks to be the most worn part of the bolt, other than that I don't see any other wear patterns that would make me want to replace anything else. Without looking at the tip of the firing pin to see if theres any cratering,

Good question. I did notice cratering in the firing pin tip but was too lazy to try to get a good macro photo. Went back now and took a photo of it vs new pin and you can see the obvious wear on the tip.



I also noticed of three different brand bolt rebuild kits and none of them had a new ejector ( I guess they figure never wear out and hard to replace) But I just ordered a new one when I ordered the Wheeler Delta block.

The kits each had a different style of "O-ring" well 2 O-rings and 1 plug. The original DPMS extractor spring had a plug.
There are one piece gas rings or standard 3 piece option too for rebuild.

[ScottsBad]

Good question. I did notice cratering in the firing pin tip but was too lazy to try to get a good macro photo. Went back now and took a photo of it vs new pin and you can see the obvious wear on the tip.

I also noticed of three different brand bolt rebuild kits and none of them had a new ejector ( I guess they figure never wear out and hard to replace) But I just ordered a new one when I ordered the Wheeler Delta block.

The kits each had a different style of "O-ring" well 2 O-rings and 1 plug. The original DPMS extractor spring had a plug.
There are one piece gas rings or standard 3 piece option too for rebuild.

OK, so if you are determined to rebuild the BCG or at least the bolt.

1. Get at least the ejector spring and ejector retainer pin. Putting a new ejector in is wise, but not absolutely necessary. You should replace the ejector spring, Sprinco make a really good one https://www.sprinco.com/ar-ejector.html. Also, I believe the spec calls for replacing the ejector retaining pin whenever you remove the ejector, but for sure if its as old as your bolt.

Colt ejector

https://www.brownells.com/rifle-parts/bolt-parts/ejector-parts/ejectors/ar15a4-ejector-prod4841.aspx

Ejector roll pin

https://www.primaryarms.com/lmt-ar-15-ejector-roll-pin

2. A majority of the builders don't recommend a one piece gas ring. And your rifle should run fine with just the black insert in the extractor spring, although you can use the doughnut. Here is a good all in one kit. Not cheap, but good quality.

https://bravocompanyusa.com/bcm-sopmod-bolt-upgrade-rebuild-kit/

Bravo also has other parts and kits.

You can get a cheaper extractor, just make sure it isn't a stamped extractor.

3. This JP Cam Pin might be good choice for an old bolt, to reduce the slop from wear.

https://www.brownells.com/rifle-parts/bolt-parts/bolt-hardware/cam-pins/enhanced-cam-pin-prod129927.aspx

Or you can buy an inexpensive one here...

https://bravocompanyusa.com/cam-pin-ar15/

4. Obviously you need a firing pin and new retainer pin.

Here is the firing pin...

https://bravocompanyusa.com/firing-pin-ar15/

[sigstroker]

Cratered firing pin is not a good sign. I haven't watched part 2 of the video that says why or how to fix it, just part 1 where it says it's bad.

[G-Man_03]

While you have the gas key off, why not replace it with a POF modified key and roller cam kit? It's a bit more money but will extend the life of your upper and run smoother.