Quoted:Built a .45 ACP fed from glock magazines on a New Frontier lower. Runs flawlessly. However, almost all the casings coming out of the gun are all dented flat on the mouth of the casing.
https://photos.app.goo.gl/F8DSBD9CUyKP6FQ49Anybody have any idea what would cause these dented casings? Im thinking they might just be hitting the brass deflector on the upper.
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I would get a used brass case that is undamaged and place it into the chamber.
Let the bolt go forward and seat against the brass.
Place a mag loaded with a few rounds into the magwell.
Now slowly pull the charging handle back and watch what happens as the brass is extracted and ejected.
At this point you can verify the bolt stops 1/8" past the bolt catch,. and isn't dragging the empty brass across the mag/bolt catch.
Also....if you are using a standard upper receiver, you might be running out of room with the ejection port and it's catching something on it's way out.
Verify you don't have signs of the brass hitting anywhere around the port.
If this is the issue....get a PCC style upper with the larger port size.