redfive0-00

you didn't say if you or your buddies were licensed gunsmith's ? QUIT GUSESSING take it some where before we all have to send flowers to your wife!!!!! The repiar on bolt lock tang is less than a quarter of what you payed for it nib

bigbulls

The slide lock (slide release) does not hold the action closed after the hammer falls. It is simply there to keep everything locked up until you pull the trigger. It has nothing to do with the action opening up upon shooting.

Take the gun apart and look at the top of the bolt. You will see a chunk of steel inside the bolt and a piece of it sticking up through the top. This piece is the locking block (part #73). This is what keeps the action locked up until you pump the gun. The steel that actually sticks up through the top of the bolt is what is the actual locking surface and is what is actually keeping the gun locked up until you cycle the action.

The Bolt slide (part #74 - or the part that the bolt sits and slides on when you take it apart) has a surface on it that pushes up the locking block into its engagement surface (square hole cut into the barrel extension).

Your problem is that the locking block is not locking into it's engagement surface. This could be caused by a number of things.
#1. check the top rear corner of the locking block and make sure that it is not burred over. #2. check the rear corner of the locking engagement surface on the barrel extension and make sure that it is not burred over. If either of these are burred over stone down the burr and see if it will lock up as burrs could prevent the locking block from fully engaging the locking surface. #3. There is a pin that holds the locking block inside the bolt. Make sure that it is not broken or bent in any way or has walked out of one side. If it is then replace it or push it back in. #4. Look at the bolt slide and make sure that the angled bit of material is not broken or excessively worn down. If it is then take it to a gunsmith. #5. Look at the bottom side of the locking block. The forward most flat surface should not be worn down excessively. If it is then take it to a gunsmith. #6. Make sure that the barrel extension is not cracked or broken behind the locking surface (square hole). If it is then replace the barrel.

If it's not any of these then I don't know what to tell you with out looking at it.

liquidorange

called mossberg today and talked to a woman who wouldnt let me talk to a tech but relayed the message back and forth to one while i was still on the phone.( thought that was wierd!) she was trying to tell me this was normal and especially with heavy loads. i said it never did that before so i insisted on sending it in. they will do the labor for free but if there are any parts it will cost me. the gun is more than 10 years old but maybe a 100 rounds through it. it is in barely used and near mint condition. it was never hunted with mostly a range gun for slugs and water jugs. i guess they will get this one back!

kelincp

I have a Mossberg 500 myself. I have the exact same problem. I've been shooting pumps all my life and this is the first time I have had that happen, so I know its the gun. I believe that is simply result of a fairly cheaply made gun and wear. My Wingmaster has fired just as many shells and has no trouble at all. In the gun world you get what you pay for.
I still use the gun for turkey since I only need one shot, but between that and the famous mossberg fore arm rattle I just will not buy one again.

liquidorange

i dont think its an issue of what brand it is or how its made because between me and my brother we have a couple model 5oo-s with never a problem. i bought a remington 1187 and it would hang up on ammo but my mossberg 9200 auto spits out everything form skeet to buckshot smooth without a hiccup and cost alot less. didnt leave me bitter about remington i still buy there guns its reallya matter of getting a good one.

dog1

liquidorange,

I think what you percieve as a problem with your pump is actually a benefit. I own several pumps and different name brands, all release the action when fired, some move the action farther than others, which makes for easier pump action, which makes a follow up shot quicker.

I don't know if Mossberg has a web site that explains this action, but Winchester does. Just type in Winchester guns and then pull up their web site. You want to see the info on Winchesters' Model 1300 (pump gun), they explain their action in detail, which is called speed pump.

Personally, if I bought a pump gun (shotgun) and it didn't do this I would be ready to do a little work on it to loosen it up. I might add that if it didn't release the action when fired, you would have to push a release button/catch every time to pump a new shell into the barrel, which would slow the firing process drastically.

Hope this helps.

dog1

bigbulls

This is not a benefit at all. If the gun is slamming open upon firing it will eventually damage the gun and could cause a very unsafe situation.

The reason that you think that the action releases by itself is because the action operates on recoil and your resistance to the recoil.

When you shoulder the gun you are pulling against the forend and applying pressure against the slide lock. When you pull the trigger and the hammer falls you are still pulling aginst the forarm keeping it locked up. The moment the charge is ignited and begins to move down the barrel the recoil process begins and your forward arm resists this recoil and actually pushes the forend forward thus releasing the slide lock before the recoil can damage it. Inside the bolt is the locking block. This is locked into the barrel extension and as your arm is pushing the forend forward the locking block is locked into the barrel extension and absorbing the recoil keeping the action from slamming open.

After the recoil process ends you are able to cycle the action by means of the forarm. Attached to the action slide arms (bars running down the mag tube) is the action slide block (what the bolt sits on). As you slide back the forarm it in turn slides back the action slide block. The action slide block moves from under the locking block and pushes the locking block down thus disengaging it from its locking engagement. With out you actually operating the action the gun will stay in the locked position. It should not release on its own.

You can test this by taking an EMPTY gun and placing a dowel rod down the barrel. Pull the trigger with out touching the forarm. Now push the dowel rod against the bolt. It should be not unlocked from the barrel extension and you should not be able to move it rearward with our actually pulling aginst the forarm. If this does not happen then something is either worn down excessively or something is broke.

liquidorange

mossberg finally got back to me. what a class operation[:@] NOT! they first of all wanted to charge me 80$ to replace slide parts AND SAID WE WILL GET BACK TO YOU. then i asked them to guarantee me that this would fix the problem. they tested the gun after new parts and said it still ejected the heavy ammo the same and said that they posted on there web site that with high brass or heavy loads to expect the action to fly open. this wasnt in my owners manual! i smell something funny( class action lawsuit). i told them if the gun is still doing the same thing why put the new parts on and charge me 80$. i told them to put the old parts back on and ship it back. i guess i will have to stick with bird shot and buy me a benelli. this will be my last mossberg!!!!![:@] i have delt with WINCHESTER, RUGER AND THOMPSON CENTER IN THE PAST AND THEY ARE THE ONLY TRUELY STAND BEHIND COMPANIES I HAVE DELT WITH!!!!. i always thought of mossberg as the gun for the average guy but after this i will spend my gun money elsewhere!

mauser06

i didnt read all the replys so sorry if i repeat it....but i think someone here or another board had the same problem and the company said its normal and its just for faster action work.....my mossberg does the same thing...the action opens half way....but i never noticed if upon recoil i pull back part way or what....i really dont care.....when im hunting or shooting quickly im raking another shell in upon recoil anyway....i work like an autoloader kinda....i let the recoil help me work the action back and work it forward and im back on target.....just the way i shoot my scatter guns i guess..........

liquidorange

i guess if it is a defect some like it but i dont. it never acted like this before and i have 2 others that dont throw open like this. i want my pump to go BOOM CHICK-CHICK BOOM REPEAT. might there be design differences through the years or cheaper parts that may cause some to open easier than others? i wonder how many have pinched hands and fingers from the forearm flying back. i will have to do a little more looking. im not done with this yet![:@]