Minor issue or life Threatening Problem???

Discussion in 'Gunsmithing' started by hgr2, Jun 21, 2014.

  1. hgr2

    hgr2 New Member

    Joined:
    Aug 4, 2013
    Messages:
    11
    Likes Received:
    2
    Been working with my M70 Safari Express 416 at my practice range for an upcoming Buff hunt in Zimbabwe this August and have started to have some troubling events occur.
    While working the bolt at rapid speeds, sometimes one or more of the rounds in the magazine will just eject themselves while the bolt is at it’s most rearward position. I know this is not the way this system is designed to function. I have several M70s with pre64 style actions from 260 on up and have never had this happen before.
    Can someone please shed some light on a fix for this?? My first thought is to find a more powerful magazine spring that will increase the upward pressure on the feed lips to prevent this from happening. Is this a valid fix?
    Thanks, hgr2
     
  2. PHOENIX PHIL

    PHOENIX PHIL AH Legend

    Joined:
    Apr 15, 2009
    Messages:
    2,605
    Likes Received:
    200
    My Photos:
    23
    Member of:
    SCI
    Hunted:
    USA, S. Africa
    I have only read of this problem in other rifles and it's been awhile. But I think you're on the right track if my memory serves corrrectly. Makes sense if the rounds are sort of floating and therefore may be able to shift around under the conditions of working the bolt more severely.

    Whatever the case, I would check with your gunsmith and get it resolved soon.
     
  3. hgr2

    hgr2 New Member

    Joined:
    Aug 4, 2013
    Messages:
    11
    Likes Received:
    2
    Thanks Phill,
    It seems that there are few here that have been effected by this malady.(I’m really lucky this way) I hope to make a good shot that will require no follow up
    The hunt will go on nonetheless and will be waiting for advise from the members here.
    Thanks, hgr2
     
  4. ornery

    ornery BRONZE SUPPORTER

    Joined:
    Jan 1, 2013
    Messages:
    32
    Likes Received:
    0
    Hunted:
    South Africa
    hgr2, post a couple of pics of the mag loaded or pm me and I'll try to help...Bill
     
  5. BnC 04

    BnC 04 TITANIUM SUPPORTER SILVER SUPPORTER AH Enthusiast

    Joined:
    Jan 30, 2011
    Messages:
    435
    Likes Received:
    169
    My Photos:
    8
    Member of:
    SCI, RMEF, DU, NWTF, NRA
    Hunted:
    USA/Canada/Europe/ Africa
    I went to a heavier spring on my M70 375 as I had that issue occur 2 or 3 times. Hasn't occured since and never had the same issue with my 416.458 WM or Lott.
     
  6. hgr2

    hgr2 New Member

    Joined:
    Aug 4, 2013
    Messages:
    11
    Likes Received:
    2
    Thanks for the responses guys. I have been studying this situation and have consulted with a couple Winchester guys and have placed an order for a 458 magazine box. Not exactly sure what the dimentional differences are yet but I'm expecting not to see the dimples on each side of the existing one(stamped 1450) and hopefully expose more of the rails in the reciever to the opening in the 458 mag box. As the blind man said, we will see.
     
  7. Parsons

    Parsons AH Senior Member

    Joined:
    May 4, 2014
    Messages:
    69
    Likes Received:
    1
    The rails not contacting enough of the round could also be the cause. Of course Do the magbox/ follower spring first. Apples to oranges kinda but I know when opening up a mauser actions feed lips to far the round can slip up and out like you are saying. Winchester design is based on mauser so this could happen but doubtful on factory gun made for the round.
     
  8. hgr2

    hgr2 New Member

    Joined:
    Aug 4, 2013
    Messages:
    11
    Likes Received:
    2
    OK guys,

    the 458 mag box was a bust!! I should have researched the length between the 416 and 458 before ordering the box. There is a spacer in the back of the box I received making it too short for 416 rds and my follower wont work either.
    I did find another mag spring that seems to be a little stronger and so far when cycling dummy rounds none have jumped out.
    Tomorrow I will give it a real live fire workout.
     
  9. PHOENIX PHIL

    PHOENIX PHIL AH Legend

    Joined:
    Apr 15, 2009
    Messages:
    2,605
    Likes Received:
    200
    My Photos:
    23
    Member of:
    SCI
    Hunted:
    USA, S. Africa
    Fingers crossed it's the spring, you should be able to return the mag box I'd think.
     
  10. hgr2

    hgr2 New Member

    Joined:
    Aug 4, 2013
    Messages:
    11
    Likes Received:
    2
    OK Guys, here’s the latest.
    After much research I called the guys over at Sunny Hill Bottom Metal and had them send me an oversized custom follower they make. The hump in the middle of the follower
    Is closer to the ejection port side than the factory follower.
    It‘s a really nice part that has lots of extra material on it to fit several applications. After receiving it I did what any good oilfield hand would do and got a good sharp file after it.
    After removing lots of extra material and adding an extra bevel the dislodging round problem seems to have disappeared. The last round in the mag now sits perfectly
    Under the receiver rail for the full length of the cartridge and feeds flawlessly with both solids and softs. I will put it thru live fire paces this weekend and am planning on shooting another
    hundred or so rounds at my practice range in the next 3 weeks before we leave for Zimbabwe. I feel really confident with this rifle now.
     
    PHOENIX PHIL likes this.
  11. PHOENIX PHIL

    PHOENIX PHIL AH Legend

    Joined:
    Apr 15, 2009
    Messages:
    2,605
    Likes Received:
    200
    My Photos:
    23
    Member of:
    SCI
    Hunted:
    USA, S. Africa
    I sense a sigh of relief.
     
  12. hgr2

    hgr2 New Member

    Joined:
    Aug 4, 2013
    Messages:
    11
    Likes Received:
    2
    I sense a sigh of relief.!!!!!!!!!!!!!!!!!!!

    Yes!!!
    Tomorrow will be the first live fire test,
    I must admit I have been awakened in a cold sweat more than once but am confident things are going to be just fine. Report to follow.
    hgr2
     
  13. hgr2

    hgr2 New Member

    Joined:
    Aug 4, 2013
    Messages:
    11
    Likes Received:
    2
    I think the fix is in!!
    the m70 functioned flawlessly today. The dreaded last round of death has disappeared. I shot off the sticks and smacked a steel plate at 140 yrds then quickly shot a paper target off hand at 70yrds then as fast as I could fire on a target at 25yrds with good results. On a reloading note, I opened a new 8 pound jug of Varget that will be used on this hunt and my velocity increased by 85 FPS with the same charge weight!! I guess that first batch of powder was considerably slower than this new one. My velocity is now +- 2380. From the bench grouping with the 400gr A-Frames and the 400gr DGS were within about 1 inch of each other with the DGS a little low right but all 10 shots were within 4 inches at 100 yrds. Going back first thing in the morning and hopefully be better on the trigger than today. I was wanking a bit with the mental anticipation of the new velocity.
     
    PHOENIX PHIL likes this.
  14. PHOENIX PHIL

    PHOENIX PHIL AH Legend

    Joined:
    Apr 15, 2009
    Messages:
    2,605
    Likes Received:
    200
    My Photos:
    23
    Member of:
    SCI
    Hunted:
    USA, S. Africa
    Way to stick with it and get it figured out!
     

Share This Page