WTF?? AR15 204 jamming issue

[capitol]

I've loaded 1000's of .204 rounds and never ran in to any issues until now.

The rifle is a 204 Ruger and has always functioned just fine. I have only run my reloads through it and its been a varmint killing machine.

Recently I've been getting a jam up. Here's what the shells look like. Anyone know what the heck is happening here??

[2shotjoe]

You have a case gauge? Are you using full length resizer die?

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[thenodnarb]

looks like you are crushing the shoulder on sizing?

[Bastard]

any pictures of loaded rounds that you haven't tried to chamber?

how old/used is the brass?

[3006mv]

full length resize, trim to length, possibly try different magazines.

[ducky_0811]

I'm going to assume these are rounds that failed to feed? Or are these rounds round that had the dent put in on seating the bullet? A little more info? Type of rifle? Bolt/gas? How many times have your loaded this brass?

[Wrangler John]

Every now and then something comes along to amaze and confound. About the only thing I can guess at is that, if these cartridges are failing to feed, they are hanging up before being chambered and the bolt is traveling forward with enough force to dent them. The area of the bolt relieved for the extractor is about the correct shape to produce such a dent. Or they are hitting the chamber edge and being jammed against it rather than exiting the magazine. Other than that, I have only seen cases with weird dents from gas leakage when fire forming brass with too light a load (photo below), but your dents are more mechanical appearing.



As to what's causing it, ask what has changed recently and go from there. It would appear that something is causing the bullets setback seen and hanging up the cases from chambering. As mentioned by other posters above, try another magazine as a start. Wild @$$ guess.

[twotacocombo]

Checked your chamber for any obstructions or buildup?

[chknlyps2]

Has anything changed recently? Different projectiles, seating depth, magazne, dropped a mag and possibly bent a feed lip, different spring in the rifle?

[capitol]

This is happening in an AR15 when shooting. The round does chamber, but the bolt doesn't close all the way.

I full length resize, they are trimmed to the correct length, brass has been loaded 3-4 times already.

I have tried other mags, but it hasn't happened a lot. Just this one range visit.

I usually use Winchester brass and this was Remington. I doubt thats an issue.

Brass fits a case gauge perfectly.

[Sky_DiveR]

Bummer. Looks like the shell was cocked going into the die while loading. I can see why the bolt doesn't close all the way. Bet it doesn't fit into a case gauge either. Never seen an AR leave that kind of mark while shooting. Sorry, I've got nothing.

[BigBronco]

Tell me about your magazine. Is it a 10/20 or a 10/30. If so how is it blocked? I had an issue with a 10/20 that was blocked with a pop rivet. on one side only. This caused the spring to compress unevenly and it would simply not work with 10 rounds. However 9 in the mag would work fine. Does it jam on the first round only or any round? Try putting one in the chamber then loading the mag.

[capitol]

Tell me about your magazine. Is it a 10/20 or a 10/30. If so how is it blocked? I had an issue with a 10/20 that was blocked with a pop rivet. on one side only. This caused the spring to compress unevenly and it would simply not work with 10 rounds. However 9 in the mag would work fine. Does it jam on the first round only or any round? Try putting one in the chamber then loading the mag.

Hmmm. I was using 10/20 pmags. This might be the problem because I dont recall this happening before. Im going squirrel shooting again this next weekend and I will note if it happens again with which magazine.

[3006mv]

chamber brush
magazine feed lips

[70 blazer]

I had some rounds look like that on a 22lr the brass didn't eject properly and jammed the brass on top of the loading round .
fixed the ejector and problem went away.