Either short stroking due to gas problem, binding, rough or fouled chamber, ammo load problems, etc.

The extractor not hanging onto the spent case during the pull or ejector binding up in the bolt face channel.

Or bolt face retracting back past the back of ejection port rear edge on stroke, with the spent casing hitting the back ejection port edge to defect the spent case back into the action.

Factory Ammo ? .. or your reloads ?

Can you post pics of the fired cases ?.. looking for scuffs, scratches, or even odd marks on your cases necks.

Just pulling the charging handle all the way back, does the same thing, without having to drive anything down the barrel in the wrong direction.

Hence on full charging handle pull on a 223 rig, face of bolt should stop 1/8"~1/4" in front of the back edge of the ejection port window.
If the face of the bolt is even with the back edge of the window, then under self cycling recoil/buffer bumper compression, then face of bolt will be behind the back edge. Here with the bolt retracting too far back,  as the spent case if begin pivoted off the bolt face at rear stroke stall, spent case will tag the back ejection window edge on the pivot off the bolt.

Ditto here on photo's of the spent case, including the area where the extractor was pulling on the rim, since the later will show if the extractor is being pulled off the rim of the spent case and the problem at hand.

Also, photo of the spent primer, since 22N chamber can vary from manufacturer to manufacturer, and what may run fine in one barrel, may have problems in other barrel that its chamber/leade is tighter instead (even with factory ammo).

Photo of chamber through the barrel extension please, since can see that the entry chamber from the back of taper entrance, to start of chamber walls, is too sharp/not chamfered rounded correctly, and this is causing the round to scrap on the way into the chamber during loading. Hence as the round is coming out of the mag and bullet enters the chamber to control the front end on a upwards angle, round releases from the mag lips and it being angle feed into the chamber as the rim is gliding up the bolt lugs at the same time.  So if the back of chamber wall is too sharp, then instead of the round being able to angle into the chamber as it coming up the bolt cleanly, the sharp edge of the chamber back wall edge will scrap the brass like you are getting instead.

Normal radius chamfer for AR barrels,



While on this barrel, the back edge to the straight wall section of the chamber straight wall has been lightly softened from just a straight sharp edge, but still too sharp for my liking.


But still need to see some fired cases out of the rig, to get an idea of the chamber wall conditions.  
If they are smooth or reamer chattered, and how well the bolt cycle unlock is, but the amount of soot on the cases.
If the chamber walls are still too rough or chattered, the bolt is unlocking too soon, or the ammo over loaded on its gas pressure producing side (different from over all working pressure that you can just read the spent primers, but the gas pressure at barrel port being too high from the burn rate of the powder being too slow to cause the bolt to unlock too soon), then this would explain the extractor begin pulled off the case rim at case pull, and why the case is not being ejected off the bolt face correctly out the ejection port window as rear buffer stall.

EDIT.. I am reading your other thread... so some of my below comments are redundant.


IMO, those cases are far more scuffed up then I would expect from chambering and un-chambering.

Are you letting the bolt chamber from the bolt release ? ... or racking the Charging handle ? ... or by chance riding the charging handle while chambering ?..... not judging, just trying to figure out the scratches.

Some of the things I see are

The large horizontal scraps... sharp edge at the end of the chamber ?

The chatter marks at the shoulder... ... another sharp enough edge to cause the marks.

The length wise marks are most likely from the magazine feed lips.

The little various dings around the shoulder end of the case body, are probably from the locking lug at ejection port side.

The reason I asked about fired case pics, was because the neck on your fired / FTEject cases looked like they are a snug fit..


Another thing to check... is the extractor claw... make sure the ends are rounded off, which allows for easy roll off of the case. I wish I remembered whose photo this is... they deserve all credit for it.

Not seeing it myself, since have hunted in a lot colder, for a lot longer, and CLP cleaned and lubed rigs will not have problems.

If bolt is not retracting back past the rear edged of ejector port, then either exactor is slipping off the rim during the chamber pull to end up with the the bolt not tight on the bolt face at back of stroke stall to be pivoted off the bolt face cleanly by the the ejector, or the ejector got bound up in the bolt face channel and did not push the spent case off the bolt face correctly.

We can see that the bolt is behind the rim of the live case, so bolt did travel back far enough to get behind the rim of the round in the mag to allow it to recover, and bolt was back far enough for the ejector to swipe the round off the bolt face (retained by the extractor to the bolt face) to get it off the bolt face and out the ejection port window.

As for lube on all the rifle parts, Breakfree CLP is fine to much lower temps than that, but if you where using some other lube that was not CLP, it could have thickened up enough to slow the normal stroke down and caused the problem in the sub temps. Hence see guys all the time trying to use grease or oils in the gun/receiver extension parts, that even at 0 temp, thicken up to the point that is will slow the cycle down majority instead.

As for freezing if you are thinking condensation on the case to chamber wall as both go from warm to cold, not a problems since if your are tumbling the cases to clean them, the media additive has wax in it to start with, and then the round being fired that would heat the case fast enough that it would melt the ice before the extraction stroke.

Simply, need to see a spent case, since either chamber problems with it not clean/smooth, or ejector is not hanging onto the spent case rim during the pull.

Still need to soften/radius chamfer the chamber back wall edges more, so the brass is not being cut/scrapped on angle loading to the chamber from it/them.

Hence the chamber back wall edges are still too sharp/not radius rounded enough, is what is causing all those lines on the case during feeding.