BCG sticking in closed position when put away warm after a match

[DixieGuns]

Been dealing with this issue on this particular rifle ever since I put it together roughy 3 years ago.
It pretty much happens like this every single time.
1: shoot 22 shots offhand, insert ECI, then 22 sitting rapid
2: insert ECI and head to the pit
3: shoot 22 shots prone rapid then insert ECI and head to the 600 for 22 more shots
4: clear rifle and toss it in its case with bolt closed, and drive home after match is over.
Get home and and bolt is stuck closed. After a good pull on charging handle the BCG frees up and moves slick and effortlessly. If I let it cool with bolt open everything operates just fine.
At first I thought it was the lube, so I went from Lucas, to clp, then to mobile1, all with the same results.
BCG is a Toolcraft NiB, and barrel is from WOA. Nothing is binding or shows any excess wear. Maybe it’s nothing or maybe I’m overlooking something very obvious.
I’ve tried cleaning it after each match and I’ve gone 5 matches without touching it. All with the same results.

[SOTAR]

Been dealing with this issue on this particular rifle ever since I put it together roughy 3 years ago.
It pretty much happens like this every single time.
1: shoot 22 shots offhand, insert ECI, then 22 sitting rapid
2: insert ECI and head to the pit
3: shoot 22 shots prone rapid then insert ECI and head to the 600 for 22 more shots
4: clear rifle and toss it in its case with bolt closed, and drive home after match is over.
Get home and and bolt is stuck closed. After a good pull on charging handle the BCG frees up and moves slick and effortlessly. If I let it cool with bolt open everything operates just fine.
At first I thought it was the lube, so I went from Lucas, to clp, then to mobile1, all with the same results.
BCG is a Toolcraft NiB, and barrel is from WOA. Nothing is binding or shows any excess wear. Maybe it’s nothing or maybe I’m overlooking something very obvious.
I’ve tried cleaning it after each match and I’ve gone 5 matches without touching it. All with the same results.

NiB can cause sticking if you don't keep a generous amount of lubricant on the bolt. I don't know the exact reason, but I know it happens. Sometimes line won't stop the sticking.

The sticking happens where the gas rings make contact with the carrier, where the bolt lugs contact the barrel extension, where the bolt talk touches the carrier, and where the bolt support ring touches the carrier.

Sometimes it's the cam pin that sticks on the firing pin.

Try a bolt that isn't NiB and I bet it stops.

If it still happens with a non NiB bolt them you may have an issue with the carrier key sticking on the gas tube.

[markm]

Try a bolt that isn't NiB and I bet it stops.

Yeah. The NiB bolt I had was a carbon fouling magnet. It looked phosphate it was so fouled.

We get this bolt sticking on the LMT MWS AR-10s all the time when they get nasty dirty. They're not NiB, but it's the same seize up that you have to break loose.

[DixieGuns]

NiB can cause sticking if you don't keep a generous amount of lubricant on the bolt. I don't know the exact reason, but I know it happens. Sometimes line won't stop the sticking.

The sticking happens where the gas rings make contact with the carrier, where the bolt lugs contact the barrel extension, where the bolt talk touches the carrier, and where the bolt support ring touches the carrier.

Sometimes it's the cam pin that sticks on the firing pin.

Try a bolt that isn't NiB and I bet it stops.

If it still happens with a non NiB bolt them you may have an issue with the carrier key sticking on the gas tube.

I will try a phosphate bolt tomorrow and report back.

Yeah. The NiB bolt I had was a carbon fouling magnet. It looked phosphate it was so fouled.

I know exactly what you mean. Just pulled it from my rifle.

[markm]

Exactly. You know? The only non mil spec finish I've tried that's good is the Np3. I have one BCG in Np3, and that sucker is nice at keeping fouling normal and cleans up nicely.

[markm]

Np3 after a very lazy wipe down and rejuice with Froglube.

[DixieGuns]

Ok here’s the update. Just as expected the NiB carrier did not stick with the phosphate AO precision bolt and cam pin. Lucas extreme gun lube, RL15 powder, and 400 primers. I also ran the NiB bolt and cam pin in the phosphate AO carrier in a separate rifle. Zero issues there as well. Both rifles were fired ~200 rounds and put away warm with bolt closed. I’ll probably be replacing the barrel in that rifle in about another 2k rounds. I have a phosphate BCG to throw in it when I do.
Now I’m off to google “why does NiB stick to NiB”

[HKGuns]

Impressive SOTAR nailed it.

Congrats on figuring out your issue.

[1168]

Now I’m off to google “why does NiB stick to NiB”

Maybe because of all the peaks and valleys? NiB under a surface microscope has a very gritty appearance. Its like looking at a forest canopy from the paratroop door. ALG claims that using NiB and NP3 on opposing surfaces reduces friction. Or maybe they said stiction; don’t recall.

Yeah, NiB stains black in use, but it doesn’t seem to affect it.

[Disciple]

Exactly. You know? The only non mil spec finish I've tried that's good is the Np3. I have one BCG in Np3, and that sucker is nice at keeping fouling normal and cleans up nicely.

Do those you have tried include hard chrome or nitride?