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AR15.COM
4/10/2005 5:30:19 PM EDT
OK, so I went out and shot my DSA para today after reciving the new (4th one) bolt.  Before I did, I checked the headspace with a set of Forester gauges.  Closes easily on the "GO" gauge, does not close with any amount of pressure on the "NO-GO" gauge.

I found a couple of pieces of brass... (that I am POSITIVE are mine), and they look like this:




I rechecked the headspace again when I got home, and it reads the same.

Is this unsafe?  What causes this, too tight headspace?

Thanks.
4/10/2005 5:37:27 PM EDT
[#1]
Sounds like to me the rifle is headspaced perfectly. You have nice ejector marks on the base of the cases. The only thing I see is where the extractor curled the case rim a little. I've seen the same thing on occassion with my FALS. Maybe not quite enough gas piston dwell but I'm not sure about that. I do believe that it comes from the bolt trying to extract the case a little early before the pressure has bled off-HTH,
Lee
ETA: I do see on looking again that there is a little primer flow back into the firing pin hole. Could be a pressure issue but I'm not sure of cause. What load were you shooting?
4/10/2005 5:39:43 PM EDT
[#2]
What about the cupped primers?
4/10/2005 5:44:18 PM EDT
[#3]
Sorry, looked again at headstamps. I see the load. I don't know why the signs of overpressure though. The headspace as you describe it is fine. Even if you had too tight headspace, the round just wouldn't chamber to begin with.
4/10/2005 5:46:07 PM EDT
[#4]
Not that that would affect pressure, but out of curiousity what is your gas set at?
4/10/2005 5:47:16 PM EDT
[#5]
5
4/10/2005 5:49:30 PM EDT
[#6]
I think I have the "pull" on the case shoulder because of a tight chamber.  It is a DSA barrel, and when it gets hot, I see the case rim start to have heavy extractor marks.  I think it might be because the chamber is tight to begin with, then it gets tighter when hot causing the shoulder to be deformed.

Just a guess.
4/10/2005 5:54:17 PM EDT
[#7]
It probably is a little tighter chamber if it's one of the DSA bbls. I think the chamber is .308 Match rather than mil dimensions. I wouldn't have expected pressure problems with that though because I thought that military ball was a little milder than commercial .308 loads-
4/10/2005 5:56:35 PM EDT
[#8]
I guess at the end of the day, my question is this:

When you see a primer that looks like that, is it indicative of an overpressure problem; or do some guns' brass just look like that?
4/10/2005 6:02:31 PM EDT
[#9]
I've never seen that much primer flow on my cases, but I've never shot that type load before either. I mainly shoot port and south african. I would probably wonder if mine looked like that too. Why don't you post your question at the falfiles? There's a lot of experience there-
Lee
4/10/2005 6:04:15 PM EDT
[#10]
I did.  No reply yet, it's a lot slower than here.