Religious Shooter Posted February 4, 2012 Share Posted February 4, 2012 I shot my LR308 in .308 yesterday. I used a go gauge previously and found the chamber to be on the short side. I was having closure problems at the range. I measured the fired cases and I got an average of -1.3 with my RCBS MIC. The reloaded ammo I was using was averaging -2. I measured some unfired factory ammo with my MIC and got an average of -2.9. I was planning to set back the shoulder of the brass for this gun to around -5. So there would be about 5-1.3=3.7 thousands of gap. I was going to load 50 or so and function fire again. If the new set-up worked I was going to load a 1000 or so rounds. What I'm concerned with is how much the headspace would grow within the first 500 or so rounds of a new barrel. I don't want to have loaded a 1000 rds only to find out that the headspace changed significantly before I had shot the 1000 rds. Should I shoot 200? 300? or ? before I load up the 1000 rounds? Link to comment Share on other sites More sharing options...
mpeltier Posted February 4, 2012 Share Posted February 4, 2012 I do not have nearly as much experiance with 308 as I do with 223 but what stands out to me in your post is that your re loads miced bigger than the factory rounds and you already know the chamber is tight. I personally would make adjustments to mirror the factory rounds and try it again. I doubt headspace of the rifle will change much in only 500 rds. It did not change at all that I could measure in my Tac-20 after several thousand rounds. Link to comment Share on other sites More sharing options...
mpeltier Posted February 4, 2012 Share Posted February 4, 2012 (edited) Ooops. The dreaded double post. Edited February 4, 2012 by mpeltier Link to comment Share on other sites More sharing options...
Religious Shooter Posted February 4, 2012 Author Share Posted February 4, 2012 I didn't actually shoot any factory ammo that day. I measured the factory ammo to have a sort of baseline to compare the other #'s with. Link to comment Share on other sites More sharing options...
mpeltier Posted February 4, 2012 Share Posted February 4, 2012 Try some. If it works fine(I suspect it will) you have the solution. If it does not I would send it back to the mfr to make right. Link to comment Share on other sites More sharing options...
Dan Sierpina Posted February 4, 2012 Share Posted February 4, 2012 The chamber headspace should not be changing in 500 rounds. If it does, you're loading way too hot! Link to comment Share on other sites More sharing options...
twodownzero Posted February 4, 2012 Share Posted February 4, 2012 Why would the chamber headspace change at all? Headspace is not a "wearable" indicator. Link to comment Share on other sites More sharing options...
Religious Shooter Posted February 4, 2012 Author Share Posted February 4, 2012 It's common to check used/old rifles for excessive headspace. I would think that old/used rifles are checked because of wear? I don't know for sure. But the replies I'm getting on the other boards are saying that the chamber headspace area doesn't grow/erode. They are contending the change can happen with bolt area (lugs and maybe face). Wear there can change the headspace. But... as you shoot a gun the chamber gets hot. You are shoving the cartridge into the chamber... the brass is expanding and is smacking the chamber... You take any piece of metal... you heat it up and you tap it hundreds/thousands of times. Sometime it retains its shape. Sometimes it doesn't. Link to comment Share on other sites More sharing options...
Chills1994 Posted February 4, 2012 Share Posted February 4, 2012 brass vs. steel, my man, brass vs. steel Link to comment Share on other sites More sharing options...
Religious Shooter Posted February 4, 2012 Author Share Posted February 4, 2012 You heat steel hot enough and anything within reason will eventually deform it. Link to comment Share on other sites More sharing options...
Chills1994 Posted February 4, 2012 Share Posted February 4, 2012 agree'ed, but like others have said, I guess on other forums, the headspace issue will be because of bolt locking lug issues/wear or even breechface erosion. I say while you have the press set up, crank out maybe 50 rounds at where/whatever shoulder set back you feel you need, take them to the range to test them out. if they function Okay and print acceptable enough groups, go back home and crank out the other 950 rounds. your "leades" will be the thing that erodes first. Link to comment Share on other sites More sharing options...
Dan Sierpina Posted February 6, 2012 Share Posted February 6, 2012 Chills, You've never seen the breech face of an Open gun after 50,000+ rounds? The soft brass pounds the hard steel, there is a depression the size of the case head. Link to comment Share on other sites More sharing options...
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