Mossy 500 Mag Tube/Receiver Threads?

KMO · January 31, 2010, 06:56 AM

I have two barrels for my Mossberg 500, a 20" and a 28". The process for switching out these barrels has become slower and slower for me, as each barrel uses a different length magazine tube. Even though I never attach these tubes more than hand-tight, and I use a small amount of grease on the threads, it's becoming more and more difficult to thread them into the receiver. Each of the tubes wants to cross-thread, so I've got to be careful not to force them in incorrectly. I end up carefully backing them out and retrying, probably at least a dozen times before I feel them threading in properly. My question...Does anyone know of a thread chaser tool to clean up the threads on both the receiver and the mag tubes?

Goatwhiskers · January 31, 2010, 08:00 AM

Don't know of a tool. The problem is that you have a steel tube and an aluminum receiver, hard vs. softer. Aluminum is not gonna stand regular removal and rethreading of the mag tube. You really need two guns before you damage the receiver threads beyond repair. Goatwhiskers the Elder

KMO · January 31, 2010, 08:18 AM

Quote:

You really need two guns before you damage the receiver threads beyond repair.

Do you mind if I print this and show it to my wife? The solution is to buy a second shotgun...not sure she'll buy that.

I work with a machinist in a side business, so I'm wondering if he may have a solution. Maybe a steel threaded insert for the receiver? Maybe he could even alter the starting point for the existing threads so the tubes find their way in more eaasily...

hogdogs · January 31, 2010, 10:39 AM

First tear it down and de grease the threads fully. Upon inspection if the threads are real good but a bit ruff, you could use a bore brush at moderately slow speed to knock the burrs off the aluminum. Then get some of the silver colored (gray bottle/tube) loc-tite brand "Anti Seize" lube. A very TINY amount is plenty... a bit messy but great stuff. There is no reason to worry about the number of times aluminum and steel go together so long as care is taken...
Brent

KMO · January 31, 2010, 10:59 AM

Quote:

...loc-tite brand "Anti Seize" lube

Thanks Hogdogs, but is this stuff really any better than the Wilson Combat white grease I'm already using?

hogdogs · January 31, 2010, 12:58 PM

The anti seize is fortified with graphite or some other similar. Grease is a lube but may not prevent oxidation, moisture intrusion or "thread galling"... the latter is where fine threads can suffer. For instance, stainless fasteners can fail to reach specified torque before the threads seize up...
Brent

ishida336 · February 1, 2010, 12:44 AM

What are you doing changing the mag tube? They OUGHT to be the same length! Especially if they are the same capacity!

5+1 is plenty for HD taking severely damaging the gun into account.

Mossberg DOES make a 28" barrel for the 7-round tubes, sold through Maverick.

guncrank · February 1, 2010, 01:31 AM

Move the barrel hanger it is silver solder to barrel and can be moved.
Of course you would need to refinish the barrel but it is doable.

CEW

KMO · February 1, 2010, 05:48 AM

Quote:

What are you doing changing the mag tube?

Quote:

Move the barrel hanger

I can't believe I'm even responding to these, but...One barrel is set up for a 5-round tube, and the other barrel for a 7-round tube. The lugs are positioned on the barrels accordingly. The process for changing out the barrel & mag tube is very simple. It can be done in about one minute. The problem in this case involves the odd style threads, which are somewhat like a metal ribbon wrapped around the tube in a spiral. Trying to change out the position of the lugs, resolder, and refinishing afterward would seem much more trouble than simply chasing the threads. It appears we've exhausted the good ideas here. I was hoping to learn about a thread tool, but apparently one doesn't exist. I'll work it out with my machinist partner & post results later...

ishida336 · February 1, 2010, 01:14 PM

They DO sell a 28-inch barrel for the 7-round tubes.
Or, alternatively, you can stick purely with a 5-round tube, and find a new or used 18.5" barrel for a much better price.

INMY01TA · February 1, 2010, 02:55 PM

Ya why not buy a 28' 8 shot barrel?

KMO · February 1, 2010, 09:03 PM

You guys are killing me...I'm trying to keep my focus on repairing/restoring the threads on these parts I already have, not buying new stuff. This particular shotgun is a LE model that I purchased after it was turned into surplus. It had barely been used, so the 7-round tube is in good shape, as well as the 20-inch barrel, which has factory rifle sights. The 28-inch barrel was bought used, but it had never been used at all. So, I'm not of a mind to replace any of these components, unless I happen to ruin something trying to resolve this minor thread dillema...

INMY01TA · February 1, 2010, 09:12 PM

Well even if you do chase the threads they're gonna be weaker than before. Odds are you'll end up here again. I'll ask another question. Why not sell the 5 shot barrel or trade for a 7 shot??

KMO · February 1, 2010, 09:18 PM

The 5-round tube is the typical factory magazine tube. It aligns with the lug on the 28-inch barrel. They make a set, just like the 20-inch barrel pairs up with the 7-round mag tube. None of these are a sloppy fit, which might be caused from overwear. It's just a matter of getting either tube started without cross-threading.

Lee Lapin · February 1, 2010, 09:37 PM

It's the RECEIVER- it isn't a 'minor thread dilemma.' But it's your gun, treat it any way you like...

lpl

ishida336 · February 1, 2010, 10:08 PM

We all know they fit together. That's why we asked why you keep changing the tube, and keep suggesting that you buy barrels for a single length tube instead. It's not particularly good for the receiver threads to be changed constantly, especially since it's steel on aluminum.

KMO · February 3, 2010, 09:38 PM

Quote:

Does anyone know of a thread chaser tool to clean up the threads on both the receiver and the mag tubes?

Above is a question from my original post. Honestly, this is a good-working shotgun, and I don't intend to buy any new parts for it to resolve this issue. Apparently, no one knows of a tool such as I described, so I'll figure it out. I was just hoping to spare a little time in case someone already knew of a tool designed for this purpose. Ease up guys...the shotgun is going to be fine...

hogdogs · February 4, 2010, 09:48 AM

Thread file...
Do a google for additional images.
This allows a gentle approach to touching it up. There is a thread file that covers every production thread...
I don't know about internal (female) threads but will work on the barrel.
Brent

joehorner · February 5, 2010, 07:08 PM

Hey KMO. Joe here. +1 on the seize. Gotta Harley with many aluminum to steel thread combos. This is where never seize shines. First you are dealing with dis-similar metals with fine thread. Bad ju-ju. Try the seize sparingly. I will go out in a blizzard if I run out and gotta have it.....Short of installing a helicoil,then rethreading the barrel.I see this as an good option. Good luck. Joe

January 31, 2010, 06:56 AM	#1
KMO Senior Member Join Date: January 13, 2008 Location: Northern Arizona Posts: 949	Mossy 500 Mag Tube/Receiver Threads? I have two barrels for my Mossberg 500, a 20" and a 28". The process for switching out these barrels has become slower and slower for me, as each barrel uses a different length magazine tube. Even though I never attach these tubes more than hand-tight, and I use a small amount of grease on the threads, it's becoming more and more difficult to thread them into the receiver. Each of the tubes wants to cross-thread, so I've got to be careful not to force them in incorrectly. I end up carefully backing them out and retrying, probably at least a dozen times before I feel them threading in properly. My question...Does anyone know of a thread chaser tool to clean up the threads on both the receiver and the mag tubes? __________________ *"In God We Trust"*

February 1, 2010, 01:31 AM	#8
guncrank Senior Member Join Date: July 15, 2006 Location: Fern Creek ,KY and Metro Louisville at large Posts: 430	Move the barrel hanger it is silver solder to barrel and can be moved. Of course you would need to refinish the barrel but it is doable. CEW __________________ Republic Arms and Armaments 07 1-502-231-1118 Machine Shop and Finishing Services to the trade and public

February 1, 2010, 09:03 PM	#12
KMO Senior Member Join Date: January 13, 2008 Location: Northern Arizona Posts: 949	You guys are killing me...I'm trying to keep my focus on repairing/restoring the threads on these parts I already have, not buying new stuff. This particular shotgun is a LE model that I purchased after it was turned into surplus. It had barely been used, so the 7-round tube is in good shape, as well as the 20-inch barrel, which has factory rifle sights. The 28-inch barrel was bought used, but it had never been used at all. So, I'm not of a mind to replace any of these components, unless I happen to ruin something trying to resolve this minor thread dillema... __________________ *"In God We Trust"*

February 1, 2010, 09:18 PM	#14
KMO Senior Member Join Date: January 13, 2008 Location: Northern Arizona Posts: 949	The 5-round tube is the typical factory magazine tube. It aligns with the lug on the 28-inch barrel. They make a set, just like the 20-inch barrel pairs up with the 7-round mag tube. None of these are a sloppy fit, which might be caused from overwear. It's just a matter of getting either tube started without cross-threading. __________________ *"In God We Trust"*

February 1, 2010, 09:37 PM	#15
Lee Lapin Senior Member Join Date: September 7, 2004 Location: SE NC Posts: 1,239	It's the RECEIVER- it isn't a 'minor thread dilemma.' But it's your gun, treat it any way you like... lpl __________________ Mindset - Skillset - Toolset. In that order! Attitude and skill will get you through times of no gear, better than gear will get you through times of no attitude and no skill.

January 31, 2010, 08:00 AM	#2
Goatwhiskers Senior Member Join Date: April 8, 2009 Location: Batchelor, La. Posts: 579	Don't know of a tool. The problem is that you have a steel tube and an aluminum receiver, hard vs. softer. Aluminum is not gonna stand regular removal and rethreading of the mag tube. You really need two guns before you damage the receiver threads beyond repair. Goatwhiskers the Elder

January 31, 2010, 10:39 AM	#4
hogdogs Staff In Memoriam Join Date: October 31, 2007 Location: Western Florida panhandle Posts: 11,069	First tear it down and de grease the threads fully. Upon inspection if the threads are real good but a bit ruff, you could use a bore brush at moderately slow speed to knock the burrs off the aluminum. Then get some of the silver colored (gray bottle/tube) loc-tite brand "Anti Seize" lube. A very TINY amount is plenty... a bit messy but great stuff. There is no reason to worry about the number of times aluminum and steel go together so long as care is taken... Brent

January 31, 2010, 12:58 PM	#6
hogdogs Staff In Memoriam Join Date: October 31, 2007 Location: Western Florida panhandle Posts: 11,069	The anti seize is fortified with graphite or some other similar. Grease is a lube but may not prevent oxidation, moisture intrusion or "thread galling"... the latter is where fine threads can suffer. For instance, stainless fasteners can fail to reach specified torque before the threads seize up... Brent

February 1, 2010, 12:44 AM	#7
ishida336 Member Join Date: December 6, 2009 Posts: 26	What are you doing changing the mag tube? They OUGHT to be the same length! Especially if they are the same capacity! 5+1 is plenty for HD taking severely damaging the gun into account. Mossberg DOES make a 28" barrel for the 7-round tubes, sold through Maverick.

February 1, 2010, 01:14 PM	#10
ishida336 Member Join Date: December 6, 2009 Posts: 26	They DO sell a 28-inch barrel for the 7-round tubes. Or, alternatively, you can stick purely with a 5-round tube, and find a new or used 18.5" barrel for a much better price.

February 1, 2010, 02:55 PM	#11
INMY01TA Senior Member Join Date: November 30, 2008 Location: Marylandistan Posts: 262	Ya why not buy a 28' 8 shot barrel?

February 1, 2010, 09:12 PM	#13
INMY01TA Senior Member Join Date: November 30, 2008 Location: Marylandistan Posts: 262	Well even if you do chase the threads they're gonna be weaker than before. Odds are you'll end up here again. I'll ask another question. Why not sell the 5 shot barrel or trade for a 7 shot??

February 1, 2010, 10:08 PM	#16
ishida336 Member Join Date: December 6, 2009 Posts: 26	We all know they fit together. That's why we asked why you keep changing the tube, and keep suggesting that you buy barrels for a single length tube instead. It's not particularly good for the receiver threads to be changed constantly, especially since it's steel on aluminum.

February 4, 2010, 09:48 AM	#18
hogdogs Staff In Memoriam Join Date: October 31, 2007 Location: Western Florida panhandle Posts: 11,069	Thread file... Do a google for additional images. This allows a gentle approach to touching it up. There is a thread file that covers every production thread... I don't know about internal (female) threads but will work on the barrel. Brent

February 5, 2010, 07:08 PM	#19
joehorner Member Join Date: March 7, 2009 Location: WNC Posts: 66	Anti Seize Hey KMO. Joe here. +1 on the seize. Gotta Harley with many aluminum to steel thread combos. This is where never seize shines. First you are dealing with dis-similar metals with fine thread. Bad ju-ju. Try the seize sparingly. I will go out in a blizzard if I run out and gotta have it.....Short of installing a helicoil,then rethreading the barrel.I see this as an good option. Good luck. Joe