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dexntex 02-20-2010 09:11 PM

Locked Breach Unlocking
Can anyone tell me what happened here? I was shooting my Mossberg 500 with an aftermarket 18Ē barrel with a 3Ē chamber. Firing 2 ĺ 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 3Ē 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? Iím at a loss for an explanation. :confused:

Virginian 02-20-2010 10:30 PM

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.

dexntex 02-21-2010 12:16 AM

Makes some sense but still confused
This makes some sense but Iím still a little confused. Obviously the slide canít be pulled back before the shot is taken but it can be after the trigger is pulled. But isnít 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 couldnít 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?

Gatekeeper 02-21-2010 12:28 AM

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

dexntex 02-21-2010 08:16 AM

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

Gatekeeper 02-21-2010 01:52 PM

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---->

robocop10mm 02-22-2010 05:31 PM

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.

Virginian 02-23-2010 12:01 AM


Originally Posted by robocop10mm (Post 234613)
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.

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.

robocop10mm 02-23-2010 12:44 PM

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.

dexntex 02-23-2010 11:15 PM

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.

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