What's up with flattened case mouths?

Jack Straw · August 2, 2002, 10:51 AM

Well I finally got to try a load in my Kimber that I have been wanting to try. I cast the bullets from Lee's 200gr. SWC mold, seated them to 1.255" and launched them with 4.3 grains of TiteGroup. As it turns out it was a good load in my gun -- accurate with little recoil. I noticed though that some of the fired brass was slightly flattened on one side of the case mouth. It wasn't severe so I don't consider it a problem, I'm just wondering what caused it and why.

Jack

Poodleshooter · August 2, 2002, 11:41 AM

Usually it's something in the extraction or ejection process. The brass impacts your weapon-sorta how AK's and Galils have the tendency to dent or almost bend their brass in half on ejection. I've noticed before, but have never really thought much about it.
Then again, you could be stepping on your brass.

stans · August 2, 2002, 02:30 PM

Sounds like the brass is impacting the ejection port wall. Unless the dents are severe, it is not a problem. If you are getting severe dents, the the port wall need to be a little lower or the extractor and/or ejector need to be tuned.

C.R.Sam · August 2, 2002, 02:54 PM

I think port alteration is a lazy substitute for proper extractor and ejector tuning.

Sam

August 2, 2002, 10:51 AM	#1
Jack Straw Senior Member Join Date: July 26, 1999 Location: Georgia Posts: 362	What's up with flattened case mouths? Well I finally got to try a load in my Kimber that I have been wanting to try. I cast the bullets from Lee's 200gr. SWC mold, seated them to 1.255" and launched them with 4.3 grains of TiteGroup. As it turns out it was a good load in my gun -- accurate with little recoil. I noticed though that some of the fired brass was slightly flattened on one side of the case mouth. It wasn't severe so I don't consider it a problem, I'm just wondering what caused it and why. Jack

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August 2, 2002, 11:41 AM	#2
Poodleshooter Senior Member Join Date: August 7, 2000 Location: Floating down the James River in VA Posts: 2,599	Usually it's something in the extraction or ejection process. The brass impacts your weapon-sorta how AK's and Galils have the tendency to dent or almost bend their brass in half on ejection. I've noticed before, but have never really thought much about it. Then again, you could be stepping on your brass.

August 2, 2002, 02:30 PM	#3
stans Senior Member Join Date: November 9, 2001 Location: Virginia, USA Posts: 838	Sounds like the brass is impacting the ejection port wall. Unless the dents are severe, it is not a problem. If you are getting severe dents, the the port wall need to be a little lower or the extractor and/or ejector need to be tuned.

August 2, 2002, 02:54 PM	#4
C.R.Sam Senior Member Join Date: October 29, 1999 Location: Dewey, AZ Posts: 12,858	I think port alteration is a lazy substitute for proper extractor and ejector tuning. Sam