LMT MRP FTE w/IMI 77 OTM Razor Core

[LMT/556]

Not sure if the rifle has the issue or ammo, I've never had this issue with the thousands of rounds fire over multiple rifles, all 556 chambered. The case stuck in the chamber with the following round jammed in behind it. Multiple attempts to close bolt and clear failed, but it only took dropping a Dewey cleaning rod down the bore to clear it. Case body and primer looked normal, not flattened or cratered. IMI is 20 headstamp 204R lot. MRP 2018 16" midlength, just cleaned it prior to this outing, maybe a couple K through it. Case edge was chewed up and knife edged but not torn off. The extractor and spring/oring all look good, H2 buffer with LMT standard carbine spring and L7D3 BCG.
Looking for some input, usually these rifle eat everything 556.

[markm]

How is your extractor condition and tension? Did it cycle fine after you cleared it?

[LMT/556]

I haven't been back out since, had to clear it at home because I didn't have a rod with me and weather yesterday was shit. Might polish the chamber with a piece of green scratch pad and chrome polish.
Extractor and spring condition both looked good to me.

[gaijin]

Extractor/Spring was my first thought too.
If it were me, I’d change spring at a minimum before heading to range again.

[LMT/556]

I have Colt gold (copper) springs as replacements.

[B Cart]

You can get a 3 pack of the BCM extractor spring upgrade kits for $12. I like to have those in my gear for replacements. I'd definitely change those out either way.