Locked Breach Unlocking

Discussion in 'General Shotgun Discussion' started by dexntex, Feb 20, 2010.

  1. dexntex

    dexntex New Member

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    Can anyone tell me what happened here? I was shooting my Mossberg 500 with an aftermarket 18” barrel with a 3” chamber. Firing 2 ¾ inch No. 6 target loads with 1 oz shot was no problem. Then I fired Remington 3 inch magnum 00 buckshot rounds. These were powerful. For four out of 5 buckshot rounds I fired, the locked breach blew open and ejected the spent shell. Everything seems OK with the barrel and all parts. The barrel fits well, fitting tight against the receiver. The barrel screw screws in tight to hold the barrel securely. When a 3” shell is chambered, the slide locks and cannot be pulled back. When the shotgun is turned upside down, I could even see the bolt rising and locking into the barrel recess. Any thoughts on how the action comes open? Is it locking but not securely? Are parts flexing? I’m at a loss for an explanation. :confused:
     
  2. Virginian

    Virginian Active Member

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    It is probably functioning exactly as designed. When the hammer drops, the action is unlocked. Otherwise, what do you think unlocks the action so you can chamber another round? During recoil the inertia of the forend, bolt, etc., keeps the breech closed, but as the gun stops the action opens. My Wingmaster does the same think with any load if I don't hold on to the fore end. Winchester claims their Speed Pump is faster because it does it, too.
     

  3. dexntex

    dexntex New Member

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    Makes some sense but still confused

    This makes some sense but I’m still a little confused. Obviously the slide can’t be pulled back before the shot is taken but it can be after the trigger is pulled. But isn’t it still the slide that unlocks the bolt. I thought sort of like you did also so I did a little check. I got a large wooden dowel that fit down the barrel all the way to the breach face. Before the trigger is pulled, the bolt couldn’t be unlocked either by pushing on the dowel or by pulling on the slide. After the trigger is pulled, the bolt could still not be opened by pushing on the dowel (simulating the push from the shell being fired) but it could be opened by pulling on the slide. In other words, the bolt remains locked until you pull on the slide even after firing. This test seems to confirm the way I think the gun should work. It stays locked until you pull back on the slide, even after firing. What do you think?
     
  4. Gatekeeper

    Gatekeeper New Member

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    It is working properly.
    Recoil moving the gun to the rear is stopped by your shoulder.
    The inertia of the slide/forearm assembly being moved to the rear from the recoil is allowing the slide to unlock the breach and eject the shell. The same as if you pulled the slide to the rear with your hand. It has nothing to do with the shell pushing on the bolt face.
    You probably wont see this happen with lighter loads due to the lighter recoil impulse.
    All my shotguns do this with heavy loads and my Rem 7600 pump rifle in 35Whelen does it as well
     
  5. dexntex

    dexntex New Member

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    OK. I get it now.

    Now I understand what you both are saying. Makes perfect sense. What I was missing is that when your shoulder stops the gun, the inertia of the slide/bolt/moving parts keeps those parts moving and ejects the shell. Thanks a bunch. Now I won't be afraid anymore to fire this gun with heavy loads, except that is, for the nasty recoil that jars my teeth and brain (and prevents me from figuring this out).:D
     
  6. Gatekeeper

    Gatekeeper New Member

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    Cool! Glad we could help. Now you see why a pump action can be operated so fast.:cool:

    Now swing by the Introductions section and tell us a little
    about yourself-- INTRO LINK----> http://www.firearmstalk.com/forums/f2/
     
  7. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    The Winchester 1300 makes this tendancy into a marketing point. They have a spring that pushes the bolt carrier away from the bolt. When dry fired, the action will open slightly. When shooting a 1300 (or a well broken in 1200) with full power ammo (like 2 3/4" buckshot) one handed, the action will open and extract/eject the empty hull. A forward shake will close/lock the action on the next round. An ideal situation if you are in a gun fight with a disabled arm.

    FWIW, 3" buckshot is just stupid. There is no real reason for it except to bruise your shoulder. Reduced recoil (tactical) buck shot kills just as dead.
     
  8. Virginian

    Virginian Active Member

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    Obviously you have never hunted deer with buckshot. Deer are about 10 times as tough as people. If they made 4" buckshot I would advise using that. I no longer deer hunt period, but I have some grim memories.
     
  9. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    I would not hunt deer with "buckshot", period. I do not think it is humane. If I lived in a buckshot only area, I would not hunt in that area. I got the heck out of one such area and moved to TEXAS, by God.
     
  10. dexntex

    dexntex New Member

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    Shotguns and Deer

    I grew up in the east (PA) but also lived in SC, NC, TX and NM. Texans have their heads screwed on straight. God bless Texas! Page 29 of the 2009 NJ Fish and Wildlife Digest allows hunting deer with a shotgun with buckshot as small as No. 4 (6 mm or 0.24", not the same as No. 4 birdshot). On page 24, it states that "Rimfire and centerfire rifles are not legal to hunt deer." Nonsense like that is why I moved west when I retired.
     
  11. Virginian

    Virginian Active Member

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    If when you were growing up everyone else was hunting with buckshot, you would have hunted with buckshot too. That's the way life is. One of the few good things about getting older is that some of us do get a little smarter.
     
  12. RMc

    RMc Member

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    Technology changes:

    Today's buckshot ammunition performance has improved dramatically!

    With traditional small buckshot like 00B, Federal's Flite Control rounds provide on target killing patterns at 40 yards that were once considered good at 15 yards.

    On the other hand Big Buckshot load developments have totally changed expectations of what buckshot is capable of. My 870 Express with a vent rib barrel and extended full choke tube, fires the Dixie Tri-Ball's three .60 caliber, 3/4th ounce hard cast pellets into 4 inch point of aim patterns at 40 yards.
     
    Last edited: Sep 13, 2010
  13. RMc

    RMc Member

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    Inertia slide lock

    The 1200,1300 and Speed Pump Winchesters do not have an inertia slide lock like the older model 12 and current 870 Remingtons and 500 Mossbergs. The inertia lock was designed to keep the action shut in the event of a hangfire. By the early 1960's hangfires had become virtually unheard of, so the Winchester 1200 pump was deemed not to need an inertia action lock. All the Winchester 1200, 1300 and Speed-Feed series slide actions will open and self eject when fired without holding the forend.

    Regardless of make, you can test your slide action shotgun for the presence of an inertia action lock by holding the forend firmly back while pulling the trigger on the UNLOADED shotgun. If the slide stays locked, your gun has an inertia action lock.

    The inertia slide lock is only important if you have a "quick" hangfire measured in miliseconds. Winchester engineers determined that by the 1964 introduction of the model 1200, such shotshell ignition problems were virtually unheard of.

    In ordinary use, the recoil of a fired round causes the forend of any slide action to move foward and unlock, the shooter will never notice the function of the inertia slide lock in those shotguns that have them.
     
    Last edited: Sep 13, 2010