Mossberg 500 Problem - Not too bad!

[270Handiman]

I've got a mossberg 500 that I won at a DU banquet.  When fired, the hulls stick in the chamber.  The ejector works fine when you cycle unfired ammo through it, but upon firing the hull stays put when the action is opened.  The chamber is clean with no obvious problems.  Has anybody ever run accross this before? 

Thanks,

270

[gunnut69]

First a couple of questions?? What do you do to get the shell out? Has the shell ever remained in the chamber after the gun opened? i.e. did the extractor jump over the rim?  Did you try pushing forward a bit on the pump arm after firing to get the stop to release? Does it hang up when the striker falls on an empty chamber? Sometimes a rusted  or pitted chamber can cause this, as can a sticking out burred stop. I'll enclose a parts blow up for up, check the link below.

http://stevespages.com/ipb-mossberg-500.html

[Gun Runner]

You wernt by chance using PMC ammo were you?. I had some of the hulls stick in my 500 after they were fired. Was shooting double "00" and slugs. Havant had any prob with other brnds of double "00" or slugs so far. Normally I have a shotgun rod with me and can tap it out. Mine woundent open untill I put the shotgun rod down and tapped it a couple times while trying to work the slide.

Gun Runner

[mountainview]

Have you tried some other brands of ammo? Sounds like the particular brand of hull you are using is expanding a bit during firing.. I occasionally get these with hulls I've scrounged and handloaded and I suspect that some brands of hulls are "softer" from the factory than others.

[gunnut69]

I don't see how soft shotshells would make a difference. The chamber is a paralell sided tube.. The metal base may expand into the extractor cut but that would show the hull. I still suspect a rough chamber or a mechanical failure causing the lockup.  Remember the plastic hull itself is quite slick and the chamber is also or should be.  Are there any marks on the fired hulls??

[dukkillr]

i've dealt with this problem with a few guns.  it's usually cheap shells.  I used to have an old Model 12 that would hang up on federals because  the brass was cheap and it would expand and stick the chamber.  I developed a passionate hatred of 1200s when i encountered one of those fine $100 shotguns that had a chamber that apparently was too tight for any shell.  It hung up on AAs and every other shell I tried. 

In summary, cheap guns, cheap shells, you get what you pay for.  I'd try other shells because it's cheaper than buying a browning BPS.

[gunnut69]

Sorry guys but it's not likely the shells.. Most brass case heads aren't brass, they're brass plated steel.. Besides what's there for the hull to hang up on??  The plastic in the tube itself is likely the softest material used in the shell that has any contact with the weapons chamber and plastic is fairly slick.. The likely problem with sticky extraction is either a rusty chamber or tool marks.. That gives the plastic something to hang on to.. The biggest difference in high priced shells and cheaper model lines is in components. Better/harder shot, shot buffering,better wads etc. Pump shotguns have nearly no primary extraction. This means they chambers must be smooth are hangups will occur.. Occassionally one finds a burr on the rim cut for the chamber or on the extractor cut. These will cause hangups but usually leave marks on fired hulls. Cheaper shotguns don't usually get the polishing they should to function well.. Also a note,,the BPS because of it's action(loads and ejects through the same port) along with the M37 Ithaca have more difficulties when the chambers get rough. They have shorter actuating cam surfaces for the lifters etc.. The do however usually have better fit and finish, so perform quite well from the box.

[dukkillr]

to say that the shells don't make any difference does not match my experience.

[gunnut69]

Sorry dukkiller-- but that's not exactly what I said.. I said they wouldn't make any difference in the function of the gun. They can and do make big differences in the results but as long as the shotgun is functioning correctly it should digest whatever factory ammo is withing tolerances. If it doesn't then the shotgun iss failing... not the ammo. Mossberg shotguns are noted chiefly for their economy, not their fine finish.. But I grew up with Mossbergs and cheap shells. They all worked just fine. I've fired tons of Federal loss leader ammo and they all worked just fine. Shotguns have nearly no primary extactiion leverage and failures to extract are common. As I said before they most often are tracable to the chamber or in the case of the M500 and a few others failure of the action to unlock at the shot.. Sometimes a push on the forearm will allow the mechainsm to unlock and the gun to function.. I the case's head was the problem there would be some mark on the case indicating a mechanical lock had been formed at the moment of firing. Lcaking that it's likely a rough chamber..either rust or machining marks.. or a mechanical failure.

----I went back reread some of my notes from past encounters with this type problem and found one thing I sound mention. Ammo that generates higher pressures will exacerbate the problem. Many times cheap ammo is loaded with faster burning powders and to reach a given velocity level they generate higher pressures, not excessive pressures but at the upper end of the norm.. That said I had cases where a high pressure load, in that case a 3 inch magnum load, was the only one that caused the problems accurance. The problem was an early opening action. While 3 inch ammo most often does not generate high pressures it generates moderate pressures for longer periods to accelerate the heavier payloads to standard speeds.. Still the problem was NOT the ammo but the gun..