• Mossberg Owners is in the process of upgrading the software. Please bear with us while we transition to the new look and new upgraded software.

Little polishing

ScottyB

ScottyB

.270 WIN
Hey guys,

Shot my 930 "War Hammer" today for some trap, shot great other than a weak hit on a primer. I know it was a bad primer because my gun wouldn't embarrass me like that.
Anyway, while cleaning it tonight I noticed an unusual amount of build up on the magazine tube where the "gas piston assembly" (the part with the rotating gas ring) normally sits on the tube. I took some very high grit sandpaper (1000-3000) and ran it (length ways) on the tube in order to remove some of the material as well as polish it. After doing so I cleaned it with some ever trusted Hoppes #9 and removed a lot of brown grime (bear in mind Id already cleaned it twice since shooting). I think the polishing removed the pits in the metal and allowed the grime to be scrubbed off. I'm hoping this simple fix will allow for between synergy of the gas system, better cycling, and as a result: better reliability.
Of course, I won't know for sure whether this modification will be to blame or if it always runs smooth just because of normal wear and a good cleaning/lunrication job.
Either way, I know this really can't hurt anything as I did nothing to the piston, but hopefully I will see some performance increase, not that she hasn't performed well to begin with (2 FTEs in like 200 shells).
 
Definitely can't hurt.

One of the features on the JM Pro models is a polished chromed mag tube. Let us know how it goes...
 
I think that is probably the one biggest thing that will improve function and reliability. The action really doesn't even need to be cleaned after shooting unless you get some dirt in it. On the other hand, the gas system is filthy. I think I should probably work on it more until it's perfectly polished. Maybe I'll do more tomorrow.
Like I said, I haven't had enough of a problem with FTEs to say whether this will help or not. Either way, I'll follow up with results.
 
I've decided to circumnavigate the issue. I'm hoping that the polishing serves to deter the carbon from depositing there.
 
Water Monkey said:
I have the same issue with carbon build up on the mag tube in this area. I usually hit it with a brass brush and liquid frog lube to get most of it off.
Click to expand...
+1 - Same here. I use a green scouring pad and liquid Frog Lube, and the carbon comes right off the mag tube. I noticed early on that keeping the mag tube, gas cylinder and gas port clean and Frog Lubed has kept my 930 cycling like a champ and it'll digest even the lighter bird/target loads without a hiccup.
 
Well, boys, I got 'er. I sanded the mag tube til it looked like it was about about 40 years old and I also lightly sanded the slip ring on the gas pistol. I haven't had problems with it jamming really, just trying to improve what already works right. Does that even make sense?
 
Dang good idea IMHO ScottyB!

This is a great forum! :cool:

looks like I found a new project for today. :)

BTW, when you said you lightly sanded the slip ring on the gas pistol, are you referring to the ID of the gas piston?

At any rate, it seems to me that as long as one doesn't go overboard and increase clearances on any of those parts, it should work and maybe even help avoid potential (or at least minimize) troublesome future deposits.

http://www.mossbergowners.com/forum/index.php?threads/bolt-not-returning-to-battery.11487/
 
Here are a few pictures of what I did. I started with 1000 grit paper and worked up to 3000 in increments of 500. I made sure to only sand length wise so that the scratches and grooves run the same direction as the operation. The portion of the gas piston that I sanded which was referring to is easily visibly silver in color. I only sanded where there was already wear marks in order to "help them along". Since doing it I haven't noticed any improvement in performance (mainly because there was no pre-existing problem). I always use Hoppe's #9 bore solvent and lubricating oil for maintainence for the record.
With regards to the bolt not returning to battery problem, I would assume that it was an issue with the bolt catch, not the gas system. If it were the gas system you would be experiencing failure to eject rounds as the bolt would never leave battery. Hope this helps.
 

Attachments

  • image.jpg
    image.jpg
    956.7 KB · Views: 89
  • image.jpg
    image.jpg
    688 KB · Views: 82
Oh...
Well I just finished up polishing what I thought you meant. :oops:

Are you saying you did the rings themselves?

I probably did the wrong darn surfaces.

But this is what I did to smooth up the travel area that the piston moves on when actuating the bolt, and it may also help with the area that Skyhawk8 seemed to be accumulating possible lead residue on.

I also did the inside of the piston surface while trying to avoid the rings, because I figured they will eventually seat themselves in much the same way automobile piston rings seat to a newly crosshatched cylinder bore.

Well what do I know anyway...what else have you polished up or modified in an effort to help with function...that job didn't take me as long as I thought it would. :D

ETA: I looks to me now that the gases bleeding out of the bore would cause the outer ring to expand and the inner ring to contract judging from the way their front angles are beveled.

Just went back over the polished tube area with 600 grit wet/dry paper in a cross-hatch pattern and the same on the inside walls of the gas chamber thinking this might be helpful.

Time to go fire it and see what happens.


 
Last edited:
Wow, you put a lot more in than I did. I really didn't take much off. Shouldn't matter. The ring I'm talking about is the gas ring on the piston which allows it to move more freely while cycling. I just sanded the outside a bit, hence the two silver lines you see on it.
This is the only mod I did to mine for functionality, everything else is just asthetic. It wasn't even necessary to do this, I was honestly just bored.
 
Sometimes one can come up with some pretty neat ideas when one is bored.

I realized that I didn't hone enough of the magazine tube initially because it occurred to me that there must be another ring where that contained spring setup is (the spring that loves to scratch the tube) that acts as a type of pressure relief valve to bleed off excessive gas through those oval ports after the piston has worked the bolt, so I increased the honing area forward some more.

Just got back from making sure I didn't screw the works up and the shotgun functioned flawlessly with the lightest loads I had on hand to test it out with.

Fun project! :) What's next? :D

 
Last edited:
After watching this video of what looked like this nice JM series 930 having problems with shell extraction (probably ammo related) I decided to give my shotgun chamber a little personal attention in the form of polishing it out with some fine polishing compound followed by some Flitz or a little Mothers mag wheel polish .

Probably not really going to make a noticeable difference on my shotgun because I haven't had an extraction problem so far but it does make me feel a little better anyway. :)



 
So today I went to Wal-Mart and found some even lighter loads to test.

The federals I tried before are 3 dram equivalent loads and these Winchester loads are 2 3/4 drams.

My 930 ate 'em up like candy!

Happy Mossberg customer! :D

 
BRL said:
So today I went to Wal-Mart and found some even lighter loads to test.

The federals I tried before are 3 dram equivalent loads and these Winchester loads are 2 3/4 drams.

My 930 ate 'em up like candy!

Happy Mossberg customer! :D

Click to expand...

I have been running these in my 930 for the last several weeks. They work in my 930 perfectly.
 
LAZY EYED SNIPER said:
Definitely can't hurt.

One of the features on the JM Pro models is a polished chromed mag tube. Let us know how it goes...
Click to expand...

Oooh, I like that. Something to remember for future use. I had a Toyota gas tank "industrial" nickle plated once. It filled the voids and corrosion proofed it. Not chrome shiney, just lite grey nickle, smooth. Would work both inside and out.
 
You must log in or register to reply here.
Back
Top