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

[DixieGuns]

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.

So in a nutshell, carbon is building up in the crevices of the NiB coating acting as a “glue”, causing mating surfaces to stick.
Good enough explanation to me. Like I said, I’ll run it until barrel change and throw it in with the other spare parts.

[MistWolf]

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.

When you say "ECI" do you mean Empty Chamber Indicator?

Assuming your answer is yes, When the ECI is inserted, do you close the bolt on it?

[DixieGuns]

When you say "ECI" do you mean Empty Chamber Indicator?

Assuming your answer is yes, When the ECI is inserted, do you close the bolt on it?

You are correct, and no, I never close the bolt on it. Bolt is only closed chambering live rounds and at the end of match.