Excessive Case Stretch

[DustBuster]

So, I bought this OVERPRICED but high Quality brass.  Lapua.

Havent shot it yet.  I have a brand new  barrel that I just did a headspace check on.  It passed the test on Both the Go and No-Go.  Clymer No-Go (1.634) wouldn’t close.  All is good with that bolt.

I then check another bolt, and this one did close on the No-Go.  I put a piece of tape on the No-Go and I measured and calculated it to be (1.636) This other Bolt would not close on this modified NO-Go.  So I figure it is an excessive .002.  With the first few firing of the new brass, the new case will Stretch more than ideal to fit my chamber.  Do you all think that I will have much Shorter life of this brass with the extra initial Case Stretch of .002 ?  I don’t plan on bumping shoulders back more than .002 each time I FL resize.  Whatchyou all Think?

Ask for exchange on this Failed Bolt or get extra stretch possibly shortening expensive brass life?

[DustBuster]

Side Info:  I measured the unfired brass an it is an average of 1.626 to the Headspace Datum.  My chamber will be around 1.632 I suspect. 

Good bolt Brass initial

Fireformed Stretch=+ .006

”Bad” Bolt Brass initial 

Fireformed Stretch=+.008 

Bad for Expensive Brass? Fewer re-uses?

 

[98Z5V]

Once you fire a brand new piece of brass, it's now fire-formed to your chamber.  Measure the length of it, fired.  Use comparator gauges, and check the length, against the shoulder.  Set your dies up so that you bump the shoulder either only 0.002" or 0.003" back from the fired length.

You'll never, ever have a problem. 

[DustBuster]

1 hour ago, 98Z5V said:

Once you fire a brand new piece of brass, it's now fire-formed to your chamber.  Measure the length of it, fired.  Use comparator gauges, and check the length, against the shoulder.  Set your dies up so that you bump the shoulder either only 0.002" or 0.003" back from the fired length.

You'll never, ever have a problem. 

Thanks for Reply 98z5v....

Yes, I agree and understand your info.  I had learned to do this before I had purchased my No-Go gauge.

My Delimna:

I have two bolt carriers now.  The one I have been using perfectly satisfies the   Go and NO Go with this new barrel chamber.  

The other new Bolt Carrier of mine I have never used, but it Failed my No-Go gauge test by .002.  This sucks because this particular bolt has a Small Diameter pin which would be “perfect” for this Lapua Palma brass I’m planning on using.  I’m not about using this small primer small flashhole brass for Supreme 1000 yard shots, but only because just before I bought the brass, all I could find was the small primers.  Now since I’ve already purchased the Severly spendy brass, other normal primers have popped up available and I say “Ohh Damn, I just blew a lot of extra money I didn’t need to!”  Since I did though,

I kind of am excited to use this new brass with either bolt but the one that might be advantageous for a a small primer, having a small firing pin, happens to Headspace to big.  I suppose if I just necked sized on that special brass I could mitigate the effects of the .002 extra stretch which will happen on this brass if I use the “bad” bolt.  I did make a fairly accurate comparator and have been using that and since I have bought the No-go, I’ve discovered that I was .0015 off of being exact with my comparator.  No big deal I just add that to my readings now.  If it were any other brass I wouldn’t care so much and I would just discover what’s gonna happen after I shoot and reload like your suggested method.  I did send a request to exchange the no-go failure bolt but I kinda of doubt I will get a reply.  

My logic is telling me that probably F/L resizing the body of the brass probably contributes more to Brass growth than having a bolt .002 out of spec.

Edited January 16, 2022 by DustBuster