Reloading 7.62/.308win

Discussion in 'Shooting, Hunting and Fishing' started by Alsacien, Aug 15, 2012.

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  1. Alsacien

    Alsacien LE Moderator

    I'm gonna bin reloading for my SLR until I can get a new barrel put on it.
    The chamber is slacker than a fat pads wife on her 4th brat, and its lunching good cases.

    [​IMG]

    This is a 2/20 failure rate on once reloaded Lapua brass. Interestingly enough the cases extracted fine, and only fell apart when get kicked off the bolt face.
    The top half of the fired cases are perfect, but from the point of failure to circa 1cm above resizing ends up shaving brass off - back of chamber is widening out too much.

    Bit hacked off as I sourced 300 Lapua new cases at a knock down price, and worked up a load that was capable of shooting 8-10cm off a bag at 100mtrs, so I thought everything was fine.
    Guess I'm gonna be using Tulammo for a while.....
     
  2. I am no expert but have you had the headspace checked?
     
  3. Lapua is high quality .308 brass and not necessarily suited to 7.62x51, sloppy, military chambers- particularly if you reload. Case head separation is probably always going to occur if you don't use 7.62, thick walled ammunition.

    Are you going to get a new barrel in .308, or at least have the chamber tolerances nipped in a little?
     
  4. Alsacien

    Alsacien LE Moderator

    That's the plan, replica barrel (fitted by an ex-REME armourer) to keep it authentic - but to civvy tolerances. Will also get the thing tuned and smoothed to extent possible staying original.

    The S & B brass I have been using is still holding up fine after 3-4 reloads. I lose a few from each batch due to bad neck pinching on extraction is all.
     
  5. Good plan. That Czech clobber isn't pretty but it is much thicker!
     
  6. What is 7.62x54?

    New one on me.

    No SLR I ever shot was chambered in 7.62x54R - the Mosin-Nagant cartridge.

    Every SLR I ever shot was 7.62x51 NATO.........

    tac
     
    • Like Like x 2
  7. Well spotted- retard fingers and mind at play :)
     
  8. Just a quick question..

    Are you full length resizing these? If so, see if you can get away with just neck resizing (or back out the FL die half a turn)

    Case separation is usually caused by cycling the brass rather than straight pressure. If you can stop cycling the brass in the lower half of the case this may prolong the life.

    Also are you using a Lee factory crimp on these? You HAVE to crimp these as you are auto feeding from a mag, but the Lee die puts less strain on the neck than using the crimp feature on a conventional die..

    DON'T try to anneal the bse of the case...! You will just end up with a ripped off rim (which, I understand, can make your eyes water..!)

    Finally... do you have a split case extractor?
     
  9. Further to HE 117's post, I thought that neck resizing for a semi auto was a bit iffy, almost a guarantee for misfeeds and extraction problems unless the sizing is checked using the appropriate head space guages (I tied it without one years ago and had an entertaining time extracting a case that just did not want to leave the chamber). I now full length resize to about 5 thou under size. Dies set up in accordance with manufacturers instructions reduce the case size by lots more, dependant on brass and chamber size, which can reduce case life dramatically.
    Tulammo, isn't that Russian? That would be ironic.
     
  10. I'm using Lapua in mine (L1A1) and have not had (touch wood) a single case head separation, some of those cases have been around upto eight times, but by then they are looking pretty shabby and I usually bin them.

    I'm pretty rutheless at binning them though if they start to show signs of separation...I use that little RCBS gizmo...casemaster or whatever it's called to check for signs after each firing. Can be a bit heart breaking at times binning Lapua brass after a couple of firings, but that's semi-autos for you....sometimes a case will show signs after only one firing even with well set up dies.

    I'm only using the Lapua because I had it left over from my M1A but will be switching to something less glamorous when these are used up. I was discussing this with a Belgium shooter a couple of months ago and he was of the opinion that Lapua wasn't the best choice for military semi autos. Another guy I know buys the surplus ammo, pulls it and reloads it with Lapua bullets and Vit Powder...but what a going on really and then bins them as they are berdan primed....I couldn't be bothered with that carry on.

    Sizing wise I'm using the Redding FL bushing comp set which really works a treat, the tension is put on the neck when you resize, so no need to crimp. Plus...if you change brass you can just buy another bushing to suit and away you go. I've set those dies up using one of those Stoney Point/Hornady tools which is also handy for checking for bent rims if you have the time & patience. You can do the die set up without one by just by starting with a lubed fired case and turning in the sizing die half or a quarter turn until the case enters and extracts freely just with your fingers. It's an easy way to stop over working the brass and get a bit more life out of your cases. I don't know if it's actually warrented, but I also marked the case while doing it this way so it went into the chamber the same way (indexed) while setting up the dies. But quite honestly the Stoney Point rig is best as there is no guessing with it.
     

  11. HE117 is talking about 'partial resizing' which is fine for a semi-auto as long as it is done with great care.
     
  12. I use Redding S dies as well, and they are excellent..

    However I m a little concerned about using ony neck tension to hold bullets while going through a semi-auto action, partularly if you are using bushing dies.. They are not really designed to be used in this way.

    I am normally very anti crimp, however auto/semi auto are my one exception. If bullet gets forced into a case by a mis feed, you can get into quite a sticky situation.

    For the benefit of those who do not know about bushing or "s" dies... These are rifle case resizing dies where you can adjust the degree of neck resizing by using exchangeable bushings. The point of this is that it allows you to "tune" the final neck size. Different case batches have different neck wall thickness, so by changing the amount of "squeeze" put in by the resizing die, you can achieve a specific neck tightness.. This is important as the neck tightness determines shot start pressure, which can affect the consistency of the burn.

    They were designed for bench rest (BR) shooters who often "tune" their cases to a rifle to achieve the most consistent muzzle velocity they can. BR shooters almost never crimp their bullets to the case as they want to minimise variations, and are using single shot rifles and hand feeding their ammuniton. The danger is that you need to set your die up for a partular case batch; switching to another case batch may result in a bullet being held very lightly in a case. On feeding through an automatic loader, there is a good chance the bullet will move in the case, leading to at best inconsitant ballistics, at worse dangerously high chamber pressures..

    Please be careful mate...!
     
  13. Alsacien

    Alsacien LE Moderator

    I use a FL die from Forster with a neck bushing that is very tight, but that works ok with HPBT matchkings. No crimp, but I have tested this fairly rigourously to ensure no forcing back into the case was occurring, both in manual cycles, and removing and measuring unfired rounds after a normal recoil cycle.

    I am reluctant to go for neck only, I have heard a lot of bad news.
     


  14. I've not read that before anywhere, but my understanding is that's exactly how they are meant to be used if loading for a semi-auto.

    If they were not fit for purpose, why do they go to the trouble of telling you to use them in that way...surely there would be big 'WARNING' messages all over the manuals about crimping after you have used them?

    Maybe my using the term 'neck tension' is misleading, however Sierra's 'Gas Gun Reloading' section refers to it as neck tension and states the best method is using a bushing die set and avoid crimping where possible. When I first got into the M1A I was pretty rigourous in gathering the best way to reload for it, including a call to Sinclair Int. who pointed me down the path I've taken no one pointed out that I'd need to crimp it too.

    Sierra do mention the Lee Factory crimp but they do seem to settle on the bushing die and increased neck tension as the best method if accuracy is what you're after.
     

  15. I can't see that you are doing anything there that will cause the separations, it's surely got to be the slack chamber/headspace and I think you've already come to that conclusion hence the re barrel in the pipeline.

    Neck sizing only is not an option, but backing your die out as HE117 suggests might be worth a try, especially as you're already on a quality bushing die.