Flatning Primers and Blowing out Primers

Discussion in 'Reloading' started by Prairie Dog50, Jan 9, 2011.

  1. Prairie Dog50

    Prairie Dog50 Active Member

    Messages:
    30
    Joined:
    Dec 14, 2010
    I am currently working up a load for my dads savage model 12fv, chambered in .22-250. The gun is extremely accurate, on multiple trips with variety of loads .37 inch groups and smaller are very common. However the gun does have one problem, it keeps flatting and blowing out primers. I have tried reducing the loads in .5 grain increments, and this has not worked. I have triple checked to make sure that I am getting correct O.A.L. length measurements of the guns chamber. So after kicking around several ideas I think at this point I'm going to try seating the bullets deeper than what I normally do. Normally when testing ammunition in a rifle I always start at .010 of the lands, and until now I have not had a problem with it, and maybe this isn't why the primers are flatting out but it's the best I know to do at this point. Do any of you guys have a better idea???lightbulb
     
  2. SBruce

    SBruce Well-Known Member

    Messages:
    1,786
    Joined:
    Oct 31, 2009
    Have you chrono'd the loads?

    What bullet weight/powder type and charge?

    What brand of primer?

    Do you know for sure the primer pockets of the case are not enlarged?

    Are your cases FL sized to the extent that they are actually moving forward at the strike of the fireing pin.?? Sometimes that can be the case even when loads aren't too hot. Excessive headspace in the chamber can account for this. Also, FL sizeing as per the die instructions can do this; especially when the chamber is a little long or large.

    The pin strikes, driving the case as far forward in the chamber as it can go. Then the bullet is no longer .010 from the lands. The pressure tries to blow the primer back (and actually does) because the case head is no longer butted up against the boltface. When the pressure forces the case rearward enough to seat the primer again, it's already been flattened.

    I can't say if that is the case in your particular situation, but I've seen it happen.
     

  3. KRP

    KRP Well-Known Member

    Messages:
    591
    Joined:
    Dec 25, 2007
    Define "blowing out primers". The primer falls out of a fired case, it's blanked, or it stands proud of the case head?
     
  4. shootinfool

    shootinfool Well-Known Member

    Messages:
    248
    Joined:
    Sep 22, 2007
    I would suspect that if its not an over pressure thing, then the primer pocket might be too large. If there has been multiple re-loads on these particular pieces of brass then you might have a streched out primer pocket issue. Is there a consistant pressure and "tightness" when you are priming the cases or do they just slip right in? You can do a crude test by priming a case and then tapping the rim on the table a little to see if the seating of the primer has changed at all or is loosened. you could also measure it if you have capabilities of doing so.
     
  5. BigSkyGP

    BigSkyGP Well-Known Member

    Messages:
    332
    Joined:
    Nov 12, 2010
    Are you using old winchester ball powder, I hear it can get a little ripe with age.

    Is your firing pin still nicely hemispherical?

    +1 for short full length sizing, and or long chamber/excessive head space.

    Check head space issue, change powder and primer.

    I once loaded some ammo for an 18" barreled auto rifle, picked up another in the same caliber only 24" barrel. Many stuck cases, and fiddling with the load. I couldn't get the powder charge low enough, new powder by the way. Had to switch to a totally different powder. The powder was too much for the long barrel.
     
  6. Trickymissfit

    Trickymissfit Well-Known Member

    Messages:
    4,070
    Joined:
    Jun 11, 2010
    take a handfull of cases that you resized, but are not primed. Now check the pockets with a primer pocket tool. If the pockets are oversized the tool will drop right in. Now is a good time to check the depth as well. The primer should be close to .005" under the face of the case head. Now is also a good time to run a small sewing machine needle thru the flash holes to see if there is an obstruction. Lastly (I know this is crazy); how big is the flash hole? I've seen some brass that had an oversized flash hole in the past. Also, by chance are you using a bushing die?

    as for a good load to start with in your Savage; try this:
    Sierra #1365 bullet seated .003" off the lands
    IMR 3031 powder @ 35.5 grains
    Federal primer

    this load will print in the twos with three Savage 22-250's, and one would print in the .180". The load is good for about 37.0 grains, but 35.5 to 36.0 grains seems to be the sweet spot. There are no pressure signs, but you will notice the chamber pressure building up. The bullet is critcal with the 1:12 twist rate!
    glt
     
  7. boomtube

    boomtube Well-Known Member

    Messages:
    1,595
    Joined:
    Oct 8, 2007
    "Are you using old winchester ball powder, I hear it can get a little ripe with age."

    The crap we can hear is incredible, especially on the world wide web of wanna be experts who got the straght skinny from a guy who's neighbor once heard from a cousin that a fellow he worked with swore he had over heard in a bar in Montanna that Winchester ball powders get a little ripe with age. Forget it, there is very little difference.
     
  8. Prairie Dog50

    Prairie Dog50 Active Member

    Messages:
    30
    Joined:
    Dec 14, 2010
    Up until this point this is the first time I have ever heard of an explanation such as this. It makes since and seems logical. Especially if savage happened to make this rifle with extra head space for varmit hunters who reload, which I would think they definitely had in mind. As far as the components go this is all first time fired full length sized brass. So as far as the primer pockets being to deep, shallow, or big I don't know? I did dechamfer and debur the case mouths. I did not debur the flash holes, and yes there are quite a few with some metal burs and uneven edges. As far as the other components I used CCI 200 large rifle primers varget and imr8208xbr. The three bullets I chose were 55 grain HNDY VMAX, 52 grain HNDY AMAX, and 55 grain Sierra HPBT. And no I have not chronographed the loads, that is the next item I plan on buying, it will be about 2 months before I can talk my wife into it. However if the chamber does have excessive head space how do I first of all verify that, and secondly what do I do to cope with or solve an excessive head space problem.
     
  9. SBruce

    SBruce Well-Known Member

    Messages:
    1,786
    Joined:
    Oct 31, 2009
    Question and Answer:

    Question; How many grains of Varget?

    CCI primers should be good.

    First fireing brass shouldn't have loose primer pockets. If you didn't ream them out and didn't deburr the flash holes excessively, then the brass is most likely good. One simple way to tell if the primers aren't deep enough is to just make sure they are below the case head when seated.

    Your Question: If the chamber does have excessive head space how do I first of all verify that, and secondly what do I do to cope with or solve an excessive head space problem.

    Answer: There are at least two ways to go about this.

    One, take it to a qualified smith and have them measure the headspace with go/no go gauges.
    If they find excessive headspace, have them set the barrel back and fix it.

    Two, buy an RCBS Precision Mic for 22-250 (they're not expensive and easy to use/understand). Read the instructions and measure the headspace from a fired case. Compare this measurement to the chart that they provide. Next, measure the headspace from a FL sized and unfired case. The difference between the two measurments (fired vs FL sized/unfired) should only be a maximum of .003". If it's more than that, you're FL sizing too much and "compressing" the case too much. Even if the chamber isn't excessive, we can make it so by running the FL sizer in too deep over the case (bumping the shoulder back too far).

    The Precision Mic also has some other functions and I highly recommend it.

    We really only want to resize just enough that the case will chamber with a very very slight resistance. Any more than this is over doing it and can lead to primer flattening and even worse, case head separation!

    I once had a 220 Swift with excessive headspace. It wasn't over the SAAMI specs, but it was on the high end. I had some handloads with flattened primers so I backed the loads way down till they weren't flat anymore. Little did I know at the time, so I continued to FL size as per the die instructions (you know, screw the die all the way down till it touches the shellholder type of thing?) Well, long story short; I started getting cases that would separate just ahead of the web, even with the reduced loads. I then found the Precision Mic and Neck Size dies. I neck sized till I absolutely had to FL size, and then only enough to chamber easily again.

    In the end, I was able to bring the loads back up to where they should be and Wallaaa........no more flattened primers and no more head separation. I bought 500 cases and got about 6 to 8 reloads per case before I finally shot the barrel out of the gun. This little fiasco was about 20 years ago, I've been using the precision mic ever since on factory rifles.
     
  10. BigSkyGP

    BigSkyGP Well-Known Member

    Messages:
    332
    Joined:
    Nov 12, 2010
    That's funny, cause I could swear that I've read, on this site multiple times, the old ball powders aren't all that stable. Things like temp sensitive, etc. So then, what is it that these rumors get started? I think there is usually an explanation, even a grain of truth in there somewhere. I never claim to be an Authority, or Expert, I do have a little experience around firarms, and some reloading under my belt. I'm still learning, maybe you can educate this backwater Montanan, on winchester ball powder.

    The powder I had a little trouble with wasn't ball powder, in fact the powder I ended up switching to is ball/spherical.
     
    Last edited: Jan 11, 2011
  11. Trickymissfit

    Trickymissfit Well-Known Member

    Messages:
    4,070
    Joined:
    Jun 11, 2010
    I don't think the chamber or excessive headspace is in the picture here. If anything, I'd suspect the chamber is cut short, rather than long. A good and simple test is to simply shoot a few factory rounds thru the barrel. You'll if something's wrong when you close the bolt (if things are too short). The easiest way to measure the overall head space is from a once fired case, and compair that to the specs on the case. And easy way is to simply take a piece of aluminum that's about .56" or greater, and drill and ream a hole about 9mm in the I.D. (size isn't critical as long it's in that area). Face it off square at both ends somewhere around 3/4". Use this to go over the neck & measure with a dial caliper. Now measure a factory loaded round. They should both be within a few thousandths of an inch. Of course you can also simply drop by a bearing outlet store and pick up an inner race close to these numbers. It will be square, and can be had for about $5.

    Also, I think I'd do about five or six rounds with a generic 50 grain bullet with about 39.0 grains of H380. The 3031 load works in every savage I've been around, but if the chamber is small I think I'd drop back about three grains and see what happens. Does sound like an over pressure spike to me, but how and why is the question.
    gary
     
  12. SBruce

    SBruce Well-Known Member

    Messages:
    1,786
    Joined:
    Oct 31, 2009
    Yes, way too small of a chamber can also cause excessive pressure. However, I've personally never had that issue. If factory rounds chamber normally, then it's not too small.

    The precision mic will also allow you to measure the headspace of loaded rounds. No need to pull the bullets, and can be used on factory cases for comparison purposes.
     
  13. Trickymissfit

    Trickymissfit Well-Known Member

    Messages:
    4,070
    Joined:
    Jun 11, 2010
    I think every reloader needs to own the Hornaday chamber measuring setup as well as the headspace bushings. This will give you seating depth as well as shoulder deminsions. I still use an old Stoney Point gauge (both sets), but the Hornaday is newer with a different thread
    gary
     
  14. Reloader222

    Reloader222 Well-Known Member

    Messages:
    206
    Joined:
    Jun 4, 2010
    I had similar problems in my .222 Rem. Thought case annealing had solve the problem, but then it had pop up again - even with lower charges. After firing I inserted a .224 decapping rod and there it was - there was a donut in the necks of all those cases which had shown execive pressure (just where the shoulder of the case start). The rod had easily inserter full lenght into all other cases which had no signs of high pressure. The conclusion is that when I insert the bullet in insert past the donut and when fired it causes a lot of pressure because the case neck cannot expand as much as it should.