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Old November 10, 2018, 10:24 AM   #22
Unclenick
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Join Date: March 4, 2005
Location: Ohio
Posts: 15,378
He finally mentioned this is a .308. It is also possible for an undercharge to do this, but it would have to be pretty severe. Another possibility is aging powder. Once the stabilizer is consumed, the acidic breakdown products can attack the deterrent coatings, causing the burn rate of the powder to go up faster than the nitrocellulose is broken down. The Navy documented this in 7.62 ball ammunition and replicated it in a laboratory with accelerated aging by application of heat. There have also been a couple of Garands blown up by surplus ammo from the late 40's. Having had powder in surplus cartridges break down, I can tell it shows up in one cartridge first, then another and then randomly more and more of them until they're all bad. Anyway, when you pull the powder from the others, I would toss it on the lawn rather than reuse it, just in case that's the problem here.

However it happened, the pressure was too high, clearly. When the ejector and extractor profiles are deeply impressed into the ejector and extractor cuts, that proves the high pressure flowed the brass excessively. The chamber also expanded and stretched to greater length than the elastic limit of the brass and when it returned to shape it clamped the brass in place. This is what holds it hard enough so you smear the brass impressions when you force the bolt open.

You will have had a bit of brass flow into the ejector tunnel and the resulting bump on the case head face was in the tunnel and sheared off when you forced the bolt open. That left brass in the ejector tunnel. The brass may be making the ejector stick. If the force was great enough it may also have bent the ejector retaining pin or the spring by driving them back hard. If you can knock the pin free, that may free the ejector, as already suggested. Likewise, a good penetrating oil left for several days may help. I enjoy experimenting, so I'd probably use an eyedropper to put some BoreTech Cu++ bore cleaner in there and let it dissolve all the brass out to see if that freed the ejector before going to penetrating oil or knocking the retaining pin out. If the pin is already out, I would apply either fluid with the bolt upright in a padded vice and lay a couple of denim rags over it to catch the ejector if it pops loose.

If the retaining pin was bent, driving a new one in may push the ejector loose, too.
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