Flattened primers, a miss fire, and worries about headspace....

Discussion in 'Reloading' started by cdherman, Sep 2, 2008.

  1. cdherman

    cdherman Well-Known Member

    Aug 9, 2008
    I have been reloading for about 25 years, though with some long intervals of time off when I was living in Massachusetts. I have had flattened primers from heavy loads and I know what they look like.

    I recently bought a new Savage 270 WSM varmiter, 26" bbl.

    Rather than buy any loaded brass, I just bought 300 rounds of Reminton brass.

    To get it sighted in and see what was going to happen, accuracy wise, and to get started breaking in the barrel, I loaded up 20 round with the lightest load in the book.

    I did use standard primers (not magnum) as I had an odd lot left over and didn't really care about velocity or accuracy.

    The gun didn't shoot so well (yes, barrel was cleaned before and after every 5 shots), but that doesn't bother me nearly so much as the flattened primers I got. All of them. With a very light load. Not really much cratering though. Bolt opened smoothly, so I really don't think this high pressure.

    AND, to make matters worse, I had one misfire. When I opened the bolt, the primer had a dent in it, but not a very good one. It fired on the second try.

    So I am worried about headspace. I understand the whole concept of the primer backing out of the case, back up agaist the bolt face, and then when the case back up (streches) to the bolt face, the primer is flattened. I would have called it that, BUT -- the misfire really bothers me. Could the gun have too much headspace?

    I've never had a handloaded misfire before, so that should argue that my primer seating technique is sound.

    I suppose it also could be the brass. Maybe too short of brass? Rem brass has a good rep though.

    Is there a way to measure to the shoulder of the brass? I don't see how to reproducibly measure that with my calipers. Ideas?
  2. AJ Peacock

    AJ Peacock Well-Known Member

    Oct 7, 2005
    Well, there is 'absolute' headspace that is measured with go and 'no go' gauges. Then there is what I'd call 'working' headspace, which is really the amount of 'space' around any particular loaded round.

    If I didn't have a go gauge, I'd use a loaded round and check your 'working' headspace. All you need is some scotch tape and a loaded round.

    The way I headspace a Savage barrel is with the use of the go-gauge and a single thickness of scotch tape. I make sure the go-gauge will chamber freely and the go-gauge with a single thickness of scotch tape will not chamber. Since Scotch tape is around .002" thick, I then know I have set the barrel to have around .001" of headspace. I just stick one thickness on the head of the go-gauge and trim it all around with an xacto knife.

    You can do the same thing with a factory round. Make sure it chambers, then add a thickness of tape, if it chambers, add another thickness. if it takes 4 thickness's to stop it from chambering, then you have around .007" headspace.

    That is what I would do to understand more clearly what is going on with your rifle.

    I had to turn the barrel on my Savage 3200WSM nearly 1/8 of a turn (removed around .006" of extra space) to get it around .001" clearance. I've heard of others that were shipped with very liberal amounts of headspace :rolleyes:, the nice thing about Savages is that they can be easily fixed at home.

    Hope this helps and didn't ramble too much.


  3. Merlin

    Merlin Well-Known Member

    Feb 24, 2008
    Hornady (used to be Stoney Point) makes one. It's called the "Head and Shoulders Gauge" that clamps on to your calipers. You can measure headspace with these. Pretty handy to set up your dies if your using a full length sizer also. Hope this helps.
  4. woods

    woods Well-Known Member

    Jun 4, 2006
    The Hornady tool, MidwayUSA - Hornady Lock-N-Load Headspace Gage 5 Bushing Set with Comparator measures the distance from the case head to the approx location of the datum line


    You just clip it onto your caliper and rezero


    then measure the case


    Keep records and you can tell how far your brass shoulder moves from a new case to a crush fit on the 3rd or 4th firing and that will give you your working headspace. That is a function of the brass manufacturer as much as the chamber of your gun.

    Don't be surprised if the measurement is as much as .020" or so. Any more than that then you will start to have problems with shoulder burn throughs and might have case head separations with too many firings on the brass. An average shoulder movement would somewhere around .010" to .012".
  5. sjadventures

    sjadventures Well-Known Member

    Dec 9, 2007
    I use the Hornady Headspace gauge and never have any head space issues anymore.