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Why rifle safety features are important - AI-AW50

Discussion in 'Rifle Country' started by Zak Smith, May 24, 2010.

  1. Zak Smith

    Zak Smith Moderator Staff Member

    A couple other SnipersHide members and I went out Sunday morning for some extreme long range shooting. There were two AI-AW's present: a GAP-barreled .260, and a factory .308; one AWSM in .338LM, and one AW50. The wind was real bad, but we were able to put a bunch of hits on a target WAY out there - we estimate 1600 or 1700 yards based on the dope we needed to apply to hit it.

    We were shooting some 750gr AMAXs through the AW50...

    ... and at some point noticed this ...


    Hmm, that's the pressure release "valve" (really a plastic disk) that covers the two vents from the bolt area. The AW50 has one such vent on either side of the receiver to safely vent pressure away from the shooter if there is a case rupture. Hey, wait, did that just fall out or something? Weird.

    Well I was convinced that it couldn't have just fallen out, so I started to look through the fired brass and here's what I found:


    So there was a gross defect in one of the LC cases. At some point we shot that round and didn't notice anything different - except it was almost certainly one of the "misses" - and kept shooting. Neither the shooter or observers noticed anything different at the time, nor did it affect the ability to make hits after the bad round (maybe 5 or 10 more rounds were shot until we noticed).

    Being able to take a ruptured case head while igniting over 230gr of powder, make the condition safe for the shooter and not even noticeable at the time, and continue shooting accurately is a very strong testament to the engineering and design that went into this gun. In a lesser gun, this failure could have caused serious injuries and rendered the rifle inoperative.

    When we went over the footage later, we actually found the footage of the bad round:


    And the obligatory "group" photo

  2. mregunz

    mregunz Well-Known Member

    Yep no dought,Safety is very impotant and goos construction on like the mod. 770 rem.And it has some serious safety features I belive I certianly,wouldn't shoot full house max reload 's in it.43,000 saami or less presure.The lug's are way to small,the press fit barrel,and the 2 piece bolt all big red flag's for weak link's I think.And in the early 1900's when 03 came out the military discovered the 2 piece firing pin was a weak link in the gun.So I belive a 2 piece bolt is just as bad....GOOD SHOOTING,Good Hunting .Those are some mighty fine.lookin rifles
  3. R.W.Dale

    R.W.Dale Well-Known Member


    you do realize that the rem 700 uses a THREE piece bolt.

    Neat report Zack!!! Could you post a pic of the plug in question in place for comparison
  4. Zak Smith

    Zak Smith Moderator Staff Member

    You can see it in the first two photos.
  5. R.W.Dale

    R.W.Dale Well-Known Member

    Ah! You most certianlly can.

    Carry on
  6. MCMXI

    MCMXI Well-Known Member

    Not necessarily .... :D ... bolt handle designed/made/indexed/TIG welded by me. Bolt made by Pacific Tool and Gauge. All three of my Remington's have these one-piece bolts now.



    Zak, how many times have those LC cases been reloaded? You mention 230gr of powder and 750gr A-MAX bullets so I'm assuming that they're reloads. Also, you state "there was a gross defect in one of the LC cases" so are you basing this on the fact that the fracture was parallel to the length of the case (axial failure because hoop stress is 2x axial stress)? A case failure due to case head separation (overworking of the brass) would be radial. Just wondering about your thought process but excellent post and superb photos as usual.

  7. Zak Smith

    Zak Smith Moderator Staff Member


    The LC cases were supposed to be once fired when I got them, and none of those had been fired more than once by me since then - so this case had either one or two firings only. It was "over 230gr", so one can probably guess what load data I was using for match reloads.

    I say it's a gross defect because of the failure it caused and the history of the cases. The best explanation I can offer is that there was a weak spot in the brass due to some unknown factor. I do not believe the brass was worked excessively based on its history. I think I will cut the brass open to see if I can determine anything else about it.
  8. MCMXI

    MCMXI Well-Known Member

    Zak, in the second to last photo there's another red "plastic" plug in the bolt ... is this also a pressure relief port?

  9. Zak Smith

    Zak Smith Moderator Staff Member

    Yes, all the red ones are that.
  10. MCMXI

    MCMXI Well-Known Member

    Hopefully the ones used by the British military are multicam versions .... that big red dot could stand out on a dull day! :D Maybe next time you can get both plugs to pop out ... good luck with your brass inspection and please post the results if you feel so inclined.

  11. Zak Smith

    Zak Smith Moderator Staff Member

    No kidding. I am good about inspecting brass while prepping it so I am pretty sure there was no visible indication of this weak point.
  12. mregunz

    mregunz Well-Known Member

    Krochus,my 700 might have a 3 piece bolt,but if it does there isn't abig gap where the head is pinned on the bolt.and the lug's on mine I measured Are7or8 times more surface lockin in the action than on a junk 770.And if ur countin the brazed bolt as a 3rd piece.I don't think that really count's as far as a 3 piece bolt.And I'am not sure my 700 has a even a 2 piece .I'll ask my gunsmith.And if it does It's 100 times sounder and better put together than a junk 770.
  13. TexasRifleman

    TexasRifleman Moderator Emeritus

    Just curious, is that a part that would normally be carried as a spare or was this a surprise to actually need another one?

    I assume there's some reason for not leaving the hole open all the time or is it covered just to keep gunk out?

    Very interesting stuff, thanks for posting it.
  14. Zak Smith

    Zak Smith Moderator Staff Member

    I believe it's just to keep stuff out of the action, since it opens to where the back of the barrel meets the front rim of the bolt. Also, in conjunction with the safety ports themselves, their absence indicates something bad happened. Per AINA's insistence, I will be sending the rifle to them so they can check all the parts exposed to gas for potential gas erosion. I would be very very surprised if anything needed to be fixed.
  15. Maverick223

    Maverick223 Well-Known Member

    Bummer, but I wouldn't want to risk the possibility of loosing the warranty by not complying with their request. I am certain all will be well though, that is one massive pressure relief port (or valve as they erroneously term it).

  16. Dave Markowitz

    Dave Markowitz Well-Known Member

    Good example of why one should always wear eye protection. Not all actions handle escaped gas that well.
  17. Zak Smith

    Zak Smith Moderator Staff Member

    I don't know if they call it a valve or a port or what -- I've never seen an official parts diagram.
  18. Malamute

    Malamute Well-Known Member

    I had a similar thing happen shooting a 1903-A3 Springfield (made by Remington) back in the 80's. I was shooting FA 28 rounds I believe. 1928 to be sure tho. I didn't notice anything happened until I had picked up brass and saw the hole in the base similar to yours. It was factory ammo. I always wondered if it was just a bad case, or if the brass had somehow weakened over time. I "saved" the rest of that ammo after that happened tho.
  19. Maverick223

    Maverick223 Well-Known Member

    Brass doesn't normally degrade over time, but I am unsure if the corrosive primers would degrade the brass (I think it might). Better send it to me for proper disposal. :D
  20. rodinal220

    rodinal220 Well-Known Member

    Do you know if the LC brass was fired through a M2 Browning??I wont use MG brass because M2s are known for being hard on brass due to M2s having generous head spacing.This could explain the incipient head failure.Most onced fired .50 brass has been fired in a MG.

    I only run virgin .50 BMG brass in my bolt gun.If you have a hard time finding virgin brass and are forced to use MG brass inspect the brass carefully.Use a simple wire tool like the one on this link to check for incipient head separation.

    Last edited: May 24, 2010

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