500A Help? Sticky action

[poor_richard]

Okay.

I bought a used/neglected 500A this week (the previous owner left it in a case too long). I’ve noticed that the action is a bit stiff/sticky. I initially thought it just hadn’t been broken in, but then I noticed that new 500’s off the shelf (as well as the other used ones I checked) had a much slicker action.

I took the gun apart like the owner’s manual said and cleaned as much as I could without taking apart the bolt assembly and trigger housing assembly. I noticed that the funky shaped block that is inside the bolt assembly seemed a bit gritty in movement, so I poured some Break Free down, then followed with some oil, let it drain, and wiped off any excess. I then used Smooth Kote, and BP-2000 Powder on any surface that looked like it had wear marks except for the slide bar tracks, which I lightly oiled. Then, after doing a function test, I pumped the action several times and checked for any excess oil. This didn’t fix the problem. This is really my first pump. I’ve used others before, but only shot maybe about 10 or 15 rounds over about 25 years, so I’m still a newbie.

I’ve been reading this section the past 1 ½ weeks, as well as shotgunworld, and recently started with TFL. It’s a lot of digging and I haven’t found anything yet, so am wondering if this is just something that I’ll just have to live with or if there is something I can do about it. Any suggestions would be appreciated.

 

[Snarlingiron]

I took the gun apart like the owner’s manual said and cleaned as much as I could without taking apart the bolt assembly and trigger housing assembly.

Can't be avoided. Break it down, clean it up, lubricate it. Removing the bolt and the trigger group aren't difficult, and if you are going to get it clean, that is what you are going to have to do.

Here is the location of a pretty nice clip of how to do it.

http://mrcompletely.blogspot.com/2005/11/mossberg-500-12-gauge-shotgun.html

 

[poor_richard]

Yeah, I also used that video. I broke it down just like in the video, and cleaned what I could (that means excluding breading down the trigger and bold assembly's).

 

[Snarlingiron]

Oops, I thought you were saying that you didn't remove the bolt and trigger group. Full disassembly of the bolt and / or the trigger group is rarely necessary.

 

[poor_richard]

That's alright. I just don't know what else to do with it. Besides shoot it. Of course.

 

[JShirley]

When I bought my last 500, I took the slide off, put molly grease on the action bars, and pumped a few hundred times. That helped quite a bit.

John

 

[poor_richard]

When I bought my last 500, I took the slide off, put molly grease on the action bars, and pumped a few hundred times. That helped quite a bit.

John

It's my understanding that that is what the treatment of Smooth Kote, and BP-2000 Powder (by Sentry Solutions) is supposed to do. Hope it works. I guess I'll have to add pumping the slide of my SG to handgun dry firing.

 

[JShirley]

Well, a quick glance at these products does show they have molly in them. I'm not certain if suspension in alcohol vs. grease may change the dynamic, though.

John

 

[poor_richard]

That's what they claim.

I guess time will tell.

What kind of moly grease did you use?

 

[JShirley]

Hell, I walked into Wally World, and went to the automotive section. Five bucks will give you enough grease to last as many years.

We used to have "grease wars" on the old KTOG group list, way back in the day. (That's where I met Johnny Guest, for that matter, back before The Firing Line existed.) Was introduced to molly, lithium, and Militec-1.

See, steel slides on aluminum frames need really good lube to prevent damage to the frame when firing a lot of rounds. Some folks used lithium, but molly seemed the overall choice for those heavy metal to metal contact areas. I still prefer using molly grease on places like slide rails for almost any firearm. I'll use other lubes for other areas, and have gone to inexpensive mineral oil (NOT mineral spirits!!!) for the occasional wipe-down to prevent rust.

John

 

[mnrivrat]

I'm going to give you a couple places to look at that might help smooth it up. Not knowing how handy or familiar you are with the insides of the gun, I will try to explain as I go.

1) The ejector on the 500 gun is a flat steel formed item that is held in place with one screw that is accessed through the ejection port. This part is formed so that the lip of the ejector rides close to the bolt so it will peal the empty cartridge base off the bolt face sending the empty case out the ejection port. I have at times seen this ejector having too much tension riding on the side of the bolt and this can bind the action somewhat. The cure it to adjust the bend on the ejector so that it rides "softly" on the left side of the bolt not causing any binding or twisting.

2.) It can be rather easy to bend a action arm on most shotguns. A bent action arm/bar can bind during the travel cycle. Check to make sure you don't have a bent arm by removing the forearm assembly and laying the action bars on a flat surface to make sure they are not twisted or bent. They will straighten fairly easily.

3.) Another sticky point on the 500 can come at the ramps for the shell lifter. Where the lifter and the bolt carrier meet to move the lifter upwards. A little buffing on the lifter at this point can help.

Hope that gives some results for you.

 

[poor_richard]

Jshirley,

The Smooth Kote is supposed to put a moly coat on the surface, but it ‘s a dry lube. Sounds like your saying that a grease is better due to the difference in materials. I’ll try some of that.

I'm going to give you a couple places to look at that might help smooth it up. Not knowing how handy or familiar you are with the insides of the gun, I will try to explain as I go.

1) The ejector on the 500 gun is a flat steel formed item that is held in place with one screw that is accessed through the ejection port. This part is formed so that the lip of the ejector rides close to the bolt so it will peal the empty cartridge base off the bolt face sending the empty case out the ejection port. I have at times seen this ejector having too much tension riding on the side of the bolt and this can bind the action somewhat. The cure it to adjust the bend on the ejector so that it rides "softly" on the left side of the bolt not causing any binding or twisting.

I’ve got the schematic from the owner’s manual, and I am somewhat familiar with guns in general. I figured that was the ejector, but didn’t give it much thought. I’ll try the grease first and look at some of your suggestions in the process.

2.) It can be rather easy to bend a action arm on most shotguns. A bent action arm/bar can bind during the travel cycle. Check to make sure you don't have a bent arm by removing the forearm assembly and laying the action bars on a flat surface to make sure they are not twisted or bent. They will straighten fairly easily.

These are the slide bars connected to the action slide assembly, correct? IIRC there is some sort of pin holding them onto the action slide assembly. Is it recommended to completely remove them, or should I be able to check when them still attached?

3.) Another sticky point on the 500 can come at the ramps for the shell lifter.

That’s the elevator, right ?

Where the lifter and the bolt carrier meet to move the lifter upwards.

I’m going off the schematic in the OM. Is the “bolt carrier” what they list as the bolt slide, or the bolt assembly.

A little buffing on the lifter at this point can help.

Hope that gives some results for you.

I’ll take a look at the gun and see if any of these are a problem. Thanks for the suggestions.

 

[mnrivrat]

These are the slide bars connected to the action slide assembly, correct? IIRC there is some sort of pin holding them onto the action slide assembly. Is it recommended to completely remove them, or should I be able to check when them still attached?

Yes - They can be checked and straightened while attached. In fact - do NOT attempt to detach them.

That’s the elevator, right ?

Yes - different manufactures have diferent terminoligy they use - the part that lifts the cartidge from the bottom of the reciever when it exits the magazine tube, and brings it in line with the chamber.

I’m going off the schematic in the OM. Is the “bolt carrier” what they list as the bolt slide, or the bolt assembly.

Yes - Bolt carrier would be another term used for this part. It is the plate that the bolt rides on, and the action arms hook into. You will note that this part makes contact with the lifter (elevator) as it travels in its stroke to operate the part up and down. It is the contact points of these two parts where some smoothing/buffing can do some good.

The two primary issues I've seen in the past however have generaly been with the action slide bars getting twisted, and or the ejector riding too tightly against the bolt.

 

[poor_richard]

Thanks a lot mnrivrat,

Glad to know I shouldn't take the action bars off. Wasn't looking forward to that.

I'll give a look at the action bars and bolt carrier, and go from there.

 

[LongRider]

Here is a slightly better video from Life Liberty etc. that shows the whole break down / reassembly process nice thing is it is a download so you can have it available on your hard drive to refer to if you run into any problems. Pretty easy task over all. If you can pull a trigger and work a pump you should be able to take your Mossberg apart and reassemble it. Check out their Range Bag for other videos for SKS , AR , AK & Glock info.
View the Mossberg 500 Disassembly/Reassembly video (WMV format):
* Small (3.7 MB)
*Large (11.8 MB)

 

[poor_richard]

As far as the grease goes, I don't have any moly grease, but I do have some of the Militec-1 grease that I got from my local gunshop. It's lithium based. Would that work, or should I get some moly?

 

[JShirley]

Militec-1 might work nicely. It's also supposed to bond with metal, and I think the additional lubricity of the grease might help.

J

 

[poor_richard]

Thanks,

I'll give it a shot.

 

[poor_richard]

Okay,

I’m thinking it may be the ejector as it seems to act this way when I tried to remove the bolt. How far out into the receiver is the ejector supposed to hang?




Inverse image at a different angle.



Heres a pic with the bolt installed.



Also. I moly coated the receiver before shooting yesterday, so those wear marks were signs of removing the moly coat when shooting yesterday.

 

[foghornl]

Hmmmmm

I'll take a look in my Mossy 500 & Maverick 88 tonight, but it does look like that ejector maybe is sticking out a bit too far. Maybe my digi-cam will cooperate, and I can get a pic or 2.

IIRC, the ejectors in my guns are flat with the side of the receiver, with just the 'Hook' sticking out to fling out the shell. {IGNORE THIS}

I think the ejector is held in place with just a big flat-head slotted screw, so if you need to get it out to flatten it, shouldn't be TOO difficult.


EDIT:

Ok, I looked in my 1990-vintage Maverick and EARLY Mossy 500A last night..Sorry, my digi-cam hates me...no pix

Ignore earlier info about ejector being flat with the receiver, see below

In the Maverick, the ejector sticks out a bit less than yours, but it does stick out, and if you work the pump slowly, you can see it moves as the bolt goes over it. The Mossy ejector sticks out the same, but the old Mossy ejector is not quite as wide where it bolts into the receiver.


I loaded a shell to see how it worked on both guns, opening bolt very slowly....As the bolt clears the ejector, it springs up a bit, to help move the shell off the extractor hook on that side. Before the bolt is all the way back, ejector has reached full height, and the shell should be free (or nearly free) from the extractor on that side. When bolt has neared the end of travel, the shell head hits the biggest part of the extractor, starting the swing the shell out of the gun. More rearward bolt movement completes this action.

Hope this is not too wordy; I wanted to see if I could describe extraction/ejection timing.

 

[poor_richard]

Thanks for the help everyone. I had taken this to Gander Mountain when I was there just to see what they might give me for it and the guy at the gun section told me the action was a bit stiff. I had suspected this because I’d looked at other 500’s and they were quite smooth. When I took it back to the dealer I bought it from, he also thought it was a bit stiffer than a normal 500. He actually took an extractor out of another used 500 that had a much smoother action, and swapped it with my extractor. It did help a little bit, but my gun was still a stiffer action than the one on the shelf that now had the extractor out of my gun (hope that’s not to confusing). He told me to take it to the gunsmith that they use for service (since I was going there anyway) and see what they said. Since it’s still under 30-day warranty, the dealer will take care of it. The gunsmiths actually said that it’s probably stiff because it’s a Mossberg (funny because the guy at GM said it’s a little stiff for a Mossberg), but that they could do some polishing that might make things a little smoother. I didn’t see any point in making my dealer spend money for some buffing when either my dealer or myself could do that (my dealer and I had both already looked for places that were binding up, including the areas that mnrivrat mentioned, without finding any). The smith also recommended that I “just shoot it”, although both the dealer and I thought it showed signs of being shot a bit. The Gunsmith did have an old Mossberg (600) that had an action similar to mine, but most of the other ones I’ve looked at are smoother.

I’ve a good relationship with my local dealer, and I’m not going to make him pay for something that even the smith wouldn’t give me an affirmation that it would definitely make a noticeable difference (that is the buffing job). When I’m at the range using the gun I don’t notice the stiff action hardly at all. The gun could be smoother (most of the Mossbergs I’ve looked at are), and I’d like it if it were. However, this is a HD beater gun that cost me almost a third of what a new gun would cost. I’m sure I’d notice a difference with a smoother action at the range if I had one, but I don’t feel it will matter as much with adrenalin pumping if I don’t notice it much at the range (looking on the bright side I suppose). I guess it is what it is.

 

[chris in va]

I have a little different problem with my 500a. It doesn't hit the primer very hard, causing misfires.

 

[mnrivrat]

It is difficult to determine the degree of the stiffness in the action via the forum here , and without having it in my hands it is hard to make judgement of wether you should have settled for what it is, or not.

I've done work on many Mossberg 500 shotguns and have yet to settle for anything less than a decent action. I'm not one to believe that just shooting it will make it alright , if it is not at least good to begin with. Sorry we don't live next door or I would take care of it.

Good luck, and good shooting.

 

[poor_richard]

Thanks mnrivrat.

I know there are 500A's out there that are smoother than this, both new and used. I don't know what degree is acceptable, but figure if I didn't notice it much on the range (knowing it was stiff), then it should be okay. I hope. There really isn't much in the way of smiths here, and the one that looked at it is the one most people go to.

On comparison, I've got a Ithaca M37 Featherlite that has a fairly stiffer action.

Could just be newb syndrome, but at any rate I think it's just one of those instances where I must "learn to fight with the gun I have".