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Posted: 1/20/2011 10:06:55 AM EDT
Noticed this mark on the cases from a friends AR. I never really looked at cases too much, but I am now considering reloading. Trying to figure out what is causing it. Shot from a BM 1/9, AR15 bolt, Federal XM193. Not a great pic. You can see the indention and it appears to have a straight line in the middle of it.
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Quoted:
If that mark is more towards the base of the case near the extractor groove what would that mean. . That the face of the bolt is retracting back past the end of ejection port, and the spent case is hitting the back of the ejection port on the way out. Pull the charging handle all the way back, and the face of the bolt should still be 1/4" to 3/8" in front of the back of ejection port. If this is not the case, the bolt face is retracting back past the back edge of the ejection port, and you do have the correct buffer in play for the depth of the receiver extension, then the tube was milled too deep or not correctly threaded on to the receiver, and cause the problem. |
| We must be talking about different things. When the bolt is on the bolt catch I measure .25 inch to the back of the eject port on 3 different guns. That is measuring from the part of the bolt that touches the catch. With bolt all the way back that measurement is 0.1 inch (handle pulled back) |
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Outer front face/edge of the bolt, and not the recess channel surface that the case rim slips into on the bolt/where the FP protrudes from.
Hence,when the case is pivoted off the bolt face and clears the most outer from edge of the bolt from face, the spent case is not slammed into the back of the ejection port, but pivoted into the defector instead. If the denting problem was that of the dent much lower on the spent case near the rim (such as the case being defected back inot the action) , then a sharper C kiss denting would be from the back of the ejection port instead. |
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