Shells droping out of Mossberg 500A

SteelyNirvana · December 30, 2006, 09:06 PM

Hi I'm new group and want to say Hi to everyone!,here's my problem.

I bought a Mossberg 500A 12 gauge brand new back in September when a local sporting goods store had them on sale.Most of the time when I go to charge it it drops shells out of the loading port. It does it when I short stroke it and when I rack it with some power behind it. I've heard this is a common problem with Mosssberg's. Is there any easy fix I can do myself or should I go ahead and contact Mossberg?. It dosen't happen all the time maybee 50/50. I really like the design of the Mossberg becuase of location of the slide release and safety thats what sold me on the gun. I'm just starting my gun collection and plan on adding a 20 gauge combo slug gun to my collection next year,I hope I won't be forced to go with an 870, because if I'm spending that much $$$ on a gun it needs to be reliable.

Whats should I do,can it be easily fixed?,or should I be a 870 man from now on?

Thanks for any input,

Brian Craig

BTW: If this helps I've ran about 150 rounds through it, and one thing I did'nt do that I should have, was completly strip it when I took it out of the box ,and completly cleaned and degreased it and lubed it with new oil. I read that this helps with brand out of the box firearms.

scottys1 · December 30, 2006, 11:27 PM

I've seen this same problem on a few Mossbergs. Not too hard to fix.

Unload it and look up into the loading port. You'll see two "fingers", one on either side of the receiver that control the shells as they feed out of the magazine. The one on the same side as the ejection port pivots up and down and usually causes no trouble. The one on the other side springs in and out as the bolt rides over it and can lose its tension over time.

You need to disassemble it enough to pull out the offending finger and carefully bend said finger outward slightly to restore its ability to block the shells from dumping out of the magazine.

My memory isn't good enough to give step by step instructions for disassembly, but you need to pull the trigger group and bolt out to access the feed finger.

SteelyNirvana · December 31, 2006, 04:25 AM

I think I may have fixed the problem but I still have a few questions.

1) Is the pivot side not supposed to touch the shell?,mine doesn't,and when bent out o-so slightly when it touch it will not feed into the chamber.

2)So I bent out the opposite side some and cycled it a few times without no problem only thing different is you can't [color=#FF0000]█[/color][color=#FF0000]█[/color][color=#FF0000]█[/color][color=#FF0000]█[/color][color=#FF0000]█[/color]-foot around when you rack it or it won't feed.You got to rack it hard and in one solid motion

3)Ever seen/heard of this problem in a brand new gun like mine?

Thanks for your help,

Brian Craig

SteelyNirvana · December 31, 2006, 02:26 PM

After some close inspection this morning,it appears that the pivot side is'nt suposed to touch the front of the rim at all.It is suposed to grab the rim from the under-side and help push it out.The oposite side is the one that holds the shell in place and when you go to rack it back the bolt puts tension on it making it lose its grip on the rim of the cartridge.Is my therory correct?

If so, maybee I should be a gunsmith instead of an elecectrician

Brian Craig

rugerdude · December 31, 2006, 02:39 PM

That's happened with mine twice, I just make sure the shell is in the tube completely and my problems disappeared.

scottys1 · January 1, 2007, 12:58 AM

Brian, you have it almost correct. The springing finger is the main one that holds the shells in the magazine when the bolt is in battery. At the same time, the pivoting finger is pivoted down out of the way.

When the slide is racked rearward, the shell in the chamber is extracted and ejected, the springing finger releases a shell from the magazine, and the pivoting finger pivots up to block the remaining shells so only one shell is released at a time. When the slide is returned forward, the fresh shell is lifted and fed into the chamber and the feed fingers return to their original positions. When they do so, the remaining shells in the magazine will drop slightly from the pivoting finger to rest on the springing finger ready for the next cycle.

If the shells dump out of the magazine with the gun in battery, the springing finger is suspect. If they dump when the slide is moved to the rear, the pivoting finger needs to be looked at.

December 30, 2006, 09:06 PM	#1
SteelyNirvana Member Join Date: December 30, 2006 Posts: 43	Shells droping out of Mossberg 500A Hi I'm new group and want to say Hi to everyone!,here's my problem. I bought a Mossberg 500A 12 gauge brand new back in September when a local sporting goods store had them on sale.Most of the time when I go to charge it it drops shells out of the loading port. It does it when I short stroke it and when I rack it with some power behind it. I've heard this is a common problem with Mosssberg's. Is there any easy fix I can do myself or should I go ahead and contact Mossberg?. It dosen't happen all the time maybee 50/50. I really like the design of the Mossberg becuase of location of the slide release and safety thats what sold me on the gun. I'm just starting my gun collection and plan on adding a 20 gauge combo slug gun to my collection next year,I hope I won't be forced to go with an 870, because if I'm spending that much $$$ on a gun it needs to be reliable. Whats should I do,can it be easily fixed?,or should I be a 870 man from now on? Thanks for any input, Brian Craig BTW: If this helps I've ran about 150 rounds through it, and one thing I did'nt do that I should have, was completly strip it when I took it out of the box ,and completly cleaned and degreased it and lubed it with new oil. I read that this helps with brand out of the box firearms.

December 31, 2006, 02:39 PM	#5
rugerdude Senior Member Join Date: July 6, 2004 Location: Tulsa, Oklahoma Posts: 1,443	That's happened with mine twice, I just make sure the shell is in the tube completely and my problems disappeared. __________________ "The SKS is a rifle, made the way they should be, out of a heavy block of crappy commie steel, set in an inletted semi-reshaped 2x4." Not my quote but I agree completely.

December 30, 2006, 11:27 PM	#2
scottys1 Senior Member Join Date: May 21, 2004 Posts: 316	I've seen this same problem on a few Mossbergs. Not too hard to fix. Unload it and look up into the loading port. You'll see two "fingers", one on either side of the receiver that control the shells as they feed out of the magazine. The one on the same side as the ejection port pivots up and down and usually causes no trouble. The one on the other side springs in and out as the bolt rides over it and can lose its tension over time. You need to disassemble it enough to pull out the offending finger and carefully bend said finger outward slightly to restore its ability to block the shells from dumping out of the magazine. My memory isn't good enough to give step by step instructions for disassembly, but you need to pull the trigger group and bolt out to access the feed finger.

December 31, 2006, 04:25 AM	#3
SteelyNirvana Member Join Date: December 30, 2006 Posts: 43	I think I may have fixed the problem but I still have a few questions. 1) Is the pivot side not supposed to touch the shell?,mine doesn't,and when bent out o-so slightly when it touch it will not feed into the chamber. 2)So I bent out the opposite side some and cycled it a few times without no problem only thing different is you can't [color=#FF0000]█[/color][color=#FF0000]█[/color][color=#FF0000]█[/color][color=#FF0000]█[/color][color=#FF0000]█[/color]-foot around when you rack it or it won't feed.You got to rack it hard and in one solid motion 3)Ever seen/heard of this problem in a brand new gun like mine? Thanks for your help, Brian Craig

December 31, 2006, 02:26 PM	#4
SteelyNirvana Member Join Date: December 30, 2006 Posts: 43	After some close inspection this morning,it appears that the pivot side is'nt suposed to touch the front of the rim at all.It is suposed to grab the rim from the under-side and help push it out.The oposite side is the one that holds the shell in place and when you go to rack it back the bolt puts tension on it making it lose its grip on the rim of the cartridge.Is my therory correct? If so, maybee I should be a gunsmith instead of an elecectrician Brian Craig

January 1, 2007, 12:58 AM	#6
scottys1 Senior Member Join Date: May 21, 2004 Posts: 316	Brian, you have it almost correct. The springing finger is the main one that holds the shells in the magazine when the bolt is in battery. At the same time, the pivoting finger is pivoted down out of the way. When the slide is racked rearward, the shell in the chamber is extracted and ejected, the springing finger releases a shell from the magazine, and the pivoting finger pivots up to block the remaining shells so only one shell is released at a time. When the slide is returned forward, the fresh shell is lifted and fed into the chamber and the feed fingers return to their original positions. When they do so, the remaining shells in the magazine will drop slightly from the pivoting finger to rest on the springing finger ready for the next cycle. If the shells dump out of the magazine with the gun in battery, the springing finger is suspect. If they dump when the slide is moved to the rear, the pivoting finger needs to be looked at.