Post subject: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

Hello all! New to the Shotgun World BB, but a hunter and shotgunner for many years.
After 35 years of faithful service afield, I am sprucing up my Mossberg 500A with a newer walnut stock and forend and I wanted to reblue some of the wear marks on the magazine tube. I need to remove the slide action tube and forend to access the mag tube, and my instruction manual (original with the gun) tells me that once the bolt carrier and bolt are removed the slide action tube arms will slip right out of the receiver. I have never been able to get the arms out of the receiver. It seems like the ends are too large to get through the receiver cuts (although I don't see how the gun could have been assembled if that were the case).
Has anyone had a similar issue and figured out how to get the action tube off the magazine tube? Thanks!
Deepwater

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

Welcome to ShotGunWorld, Deepwater! Once the bolt slide is out, the slide action bars are free, allowing the forend / slide assembly to slip off the magazine tube.
[youtube]http://www.youtube.com/watch?v=oKbWcPdTRBI[/youtube]

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

wfb18 - thanks for your reply and the helpful video. Yes, I have taken all of the other components out of the receiver (bolt, bolt carrier, shell interupter, trigger assembly, elevator, etc.) many times in the course of normal cleaning and maintenance of my gun. Even with everything else removed, the action bars still will not clear the cuts in the receiver!

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

On mine I had to squeeze them together slightly to pop them out of the reciever cuts.

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

I had this exact problem. I don't want to sound like a jerk, but are you sure you have a 500? Mine was a Westernfield, and another was a New Haven, nearly exact to a 500, and I had to unscrew the magazine tube to get the action bars out, because they used a system on the mag. tube that was supposed to keep the forearm from rattling that does not allow it to slide off like on a 500. In every other respect they are a 500. I mean no disrespect, but it took me quite a while to figure this out, darn near drove me crazy.

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

Thanks to all for your advice. Last night I again diassembled my 500 and tried to remove the forend, but it still won't go. I think you may be on to something, Neanderthal - even though it's a genuine Mossberg, I've come to believe that there may be some sort of retainer spring around the mag tube. When the forend stops short of allowing the arms to exit the receiver cuts, there's a slight 'give' to it. Looks like I'll have to figure out how to remove the mag tube from the receiver without damaging it.
UPDATE: Stopped by Harbor Freight on the way home and picked up a pair of strap wrenches for $4.99. Fieldstripped my shotgun and padded the receiver in a woodworking vise and attached both wrenches to the mag tube. After much straining and grunting the tube came off without damage. Lo and behold the mag tube had not one, but two collars soldered to it, along with a spring to dampen the forward movement of the slide. Happy to say the tube has a nice new blue job and all is well.
Thanks to all for the advice and help!

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

Three questions, please, Deepwater? Can I assume that both your receiver and barrel have the Mossberg stamp or engraving? If so, then did you buy your Mossberg used from someone who modified your slide assembly? And when did you buy your Mossberg and when did your Mossberg leave the factory, sir?
I ask these questions because your introductory post said that you had fielded your Mossberg for 35 years, so we know that your slide assembly problem had nothing to do with the integral Maverick forend/slide assembly that migrated onto certain Mossberg models since 2006. Thank you.

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

Glad to oblige. I received my Mossberg 500 brand new out of the box in December, 1974. The receiver is stamped on the bottom just fore of the loading port as 'Mossberg, Model 500AT.' The 'G' prefix in the serial number indicates manufacture around that year. It has been my main hunting gun all of the 35 years since then and has been in my posession the entire time - it has never been taken to a gunsmith or loaned out. I still have the original Mossberg barrel (a 30' full choke plain) that came on it, but have since upgraded to a newer 28' VR with choke tubes since I couldn't use steel shot with the original barrel. The shotgun has never been modified and as I said in my original post, I had never been able to remove the action slide tube in the 35 years I have owned it until now. That's the way it came from the factory!

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

Deepwater, I hope that you will ask Mossberg about this, just for the sake of history. 'Lo and behold the mag tube [you mean 'action slide assembly', don't you?] had not one, but two collars soldered to it, along with a spring to dampen the forward movement of the slide.' If you get an answer, I would like a P.M., please. You could call Mossberg but they may not have time to answer you because it is no longer a pressing issue: 1-800-363-3555 . You may have better luck with e-mail: service@mossberg.com or snail mail: O.F. Mossberg & Sons, Inc., 7 Grasso Ave., North Haven, CT 06473
ETA: Two photographs from Gunbroker are no longer available, Sorry.

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

wfb18 - The photos attached to your post show exactly what my 500 looks like. The wooden forend is the same stained hardwood with the grooves cut in it. What I meant when I posted 'mag tube' is the magazine tube (#27 on the diagram). That is the part that has the two external collars positioned midway on the tube (about 3' apart). A short flat spring is wound around the tube (about 1 1/2 turns) and is attached to the rearward collar (towards the threaded end of the magazine tube that screws into the receiver). The two collars provide the bearing surface that the slide action tube (#28 on the diagram) rides on when the action is worked. A constriction at the rear of the slide action tube contacts the spring as the action is closed and keeps the forend assembly from rattling when the action is locked (ingenious, yes?). This was the reason I couldn't get the assembly off when the bolt was removed - it simply would not travel beyond the spring and rear collar on the magazine tube.
I watched another Youtube video about maintaining the M 500 that was a preview of a gunsmithing course, and mention was made that this spring might be encountered on older Mossbergs and New Havens, and that the magazine tube would have to be removed in order to remove the slide assembly (as I discovered), so evidently this isn't unusual. Thanks.

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

Deepwater, thanks for taking the time to detail that for me. I was clueless about your 500 AT. So Mossberg solved the rattling forend problem many years ago, but they had to abandon their solution in order to keep user disassembly uniformly easy amongst all their different models? I would sure like a couple of pictures of that slide assembly on the mag tube, the next time that you have the barrel off, if you don't mind?

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

I'm thinking the main reason is what most things boil down to-$$$. This had to add to the cost of manufacturing the gun. I have two like that, and I'm not sure if they rattle less or not, or how much less. I never minded the rattle, anyway. But then, I've owned Dodge cars, too!

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

I heard that, Neanderthal - I've got one in the driveway right now!

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

I own a 500a and a 1972 plymouth Cuda 440 6 pack auto trans. Both are in great shape too.

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

I too have a very early Mossberg 500 ATP8 inherited from my father. He never shot it and neither have I ..yet. It sat around so long the lubrication had hardened in some places. The magazine tube does indeed need to be removed before the slide can be removed.
The mag tube has been 'cemented' in place with some sort of thread locker. With the receiver held in a vise on either side of the place where the tube screws into the receiver (with proper protection for the receiver's surfaces) the tube would not budge when using both hands.
Using a heat gun the receiver was heated right where the mag tube screwed in to it while it was still held in the vise. After a minute or so of heating I was able to unscrew the mag tube by hand without too much effort.
On removal the two collars were obvious along with the flat spring. The collars are brazed in place so they are not about to come off.

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

Welcome to ShotgunWorld, Zookeeper. Your first post is excellent and I appreciate your clarifying photograph. If you could please share the serial number of your father's (now your) 500ATP8 by concealing the last three digits with XXX, I will approximate the year of manufacture for you, if you have not already done so. Good luck, sir.

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

Thank you so much for this old post. I own a Mossberg 500 ALM model that I bought new probably 40 years ago. I no longer hunt and am putting a new Hogue stock and forend on the slug barrel to use this more for a tactical, home defense shotgun.
I disassembled the shotgun yesterday to give it a thorough cleaning and for the life of me could not figure out why the slide wouldn't come off. I probably spent 10 minutes fiddling with it and then decided to do an internet search which led me to this thread.
Again thanks so much not only for the information but also for saving a little bit of sanity.

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

Wow...I have the same damn problem. I bought my Mossberg 500AT 15 years ago and have never used it at all. I decided to take it out of the cupboard and give it a clean. I almost smashed it trying to force the forearm and action tube over the mag tube. I found the spring on the floor and had no idea where it came from. Now I know..Thank you all the way from South Africa
[quote='Deepwater'][quote='wfb18']Three questions, please? Can I assume that both your receiver and barrel have the Mossberg stamp or engraving? If so, then did you buy your Mossberg used from someone who modified your slide assembly? And when did you buy your Mossberg and when did your Mossberg leave the factory, sir?[/quote]
Glad to oblige. I received my Mossberg 500 brand new out of the box in December, 1974. The receiver is stamped on the bottom just fore of the loading port as 'Mossberg, Model 500AT.' The 'G' prefix in the serial number indicates manufacture around that year. It has been my main hunting gun all of the 35 years since then and has been in my posession the entire time - it has never been taken to a gunsmith or loaned out. I still have the original Mossberg barrel (a 30' full choke plain) that came on it, but have since upgraded to a newer 28' VR with choke tubes since I couldn't use steel shot with the original barrel. The shotgun has never been modified and as I said in my original post, I had never been able to remove the action slide tube in the 35 years I have owned it until now. That's the way it came from the factory![/quote]

Post subject: Re: Mossberg 500 - Slide Arms Can't Be Removed From Receiver

Welcome to ShotgunWorld, DeanBlom.