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OR3GUN Marine Spacer Tube for Mossberg 930/935

DHonovich

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Staff member
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"Philanthropist"
http://www.oregun.com/OR3GUN/about_or3gun_marine.htm

The OR3GUN Marine Spacer Tube (MST-930) for Mossberg 930/935 series shotguns is a major enhancement to the reliable function of your firearm in all weather conditions.
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$49.95 $44.95 Introductory Pricing
For years, competition shooters like ourselves have battled seemingly random cycling malfunctions with the gas systems in Mossberg's 930/935 series. This has been a point of personal frustration for most of the OR3GUN team, as we invested heavily in the 930 platform due to the reasonable cost of running duplicates and the 'lefty friendly' nature of the guns. Our Patent Pending product is not only the solution for many of these frustrating cycling issues, it is the first device to acknowledge there is a problem that needs to be addressed in the first place.
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The OR3GUN Marine Spacer Tube replaces the Mossberg OEM ‘Gas Piston Spacer Tube’ (located inside the forend) during the course of a normal shotgun cleaning. This OEM spacer is where you typically find a buildup of carbon fouling, dirt and in many environments, water. Moisture from humidity, condensation, dew point and precipitation is the often ignored component in the 'random' malfunctions experienced with the 930 platform. Most people don't think to consult their local meteorologist to help troubleshoot their shotgun. In addition to the functional issues created by the changes in weather conditions, often times the resulting moisture is only discovered hours or days later when it has also begun to corrode the magazine tube.
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The factory OEM spacer tube exists only to passively transfer the energy of the gas piston to the pusher assembly. Mossberg utilizes a tightly fitted aluminum tube over the existing steel magazine tube. A number of unforeseen problems are set in motion by this component as humidity and round count can conspire to slow the cycling of the gas system to the point of malfunction.

The MST-930 was engineered to be an active component in keeping your gas system functioning at peak reliability. This was accomplished by designing an entirely new part with a carefully engineered feature set. This cutaway of one of our original production prototypes highlights some of these features in detail.
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A relief is incorporated within the center section of the tube in order to minimize contact between dissimilar metals, greatly reducing the amount of condensation formed. This relief also reduces contact of friction surfaces by more than 75% for smoother cycling. The oversized outside diameter of our Marine Tube is stronger and more durable while engineered to be 10% lower in overall weight for faster cycling shot to shot.

A matrix of holes in the relieved center section of the tube allows transient gas pressure to actively expel moisture, carbon and dirt during normal cycling of the gas system. The holes also allow the part to vent while cooling, greatly reducing trapped moisture which can lead to corrosion if cleaning is delayed.
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The end sections of the tube are the same inside diameter as the OEM part, creating narrow contact rings that squeegee the buildup of moisture, carbon fouling, dirt and excessive lubrication from the magazine tube. This debris would otherwise form slurry and slow the OEM part through hydraulic friction or resistance. Instead, this debris comes to rest inside the plastic forend of the shotgun where it harmlessly awaits the next regular cleaning. Each ring is designed so that it will travel further than its length during cycling for the most effective shedding of debris.

The anodized finish of the OR3GUN MST protects the part itself from corrosion and won’t flake, chip or peel over the lifetime of the component. The finish also enhances the durability, ease of cleaning and efficient heat-transfer properties of the MST.

Check out our newest YouTube video, detailing one of the common problems that can be fixed by installing the OR3GUN Marine Spacer Tube in your Mossberg 930 Jm-Pro.


The OR3GUN Marine Spacer Tube for Mossberg 930/935 series shotguns is an active component in keeping your gas system functioning at peak reliability.
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Here are some pictures from when I installed one on my personal Mossberg 930:
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Interesting. Thanks for the info Dan
 
Mmhh...

For those who can't or won't clean his gun respectively the magtube regularly!?
Otherwise I can't see a good due :-/
Correct me if I wrong! But it looks cool. Pity that you can't see it under the grip ;-)
 
Just ordered one yesterday. Been having some issues with my 930 and have been working to fix them. Hope this will help.
 
Just ordered one yesterday. Been having some issues with my 930 and have been working to fix them. Hope this will help.
If you don't mind me asking, what kind of troubles (not to hijack the thread)? The single most helpful thing for me was watching Miculek himself go though the cleaning process on youtube.

More on topic, this looks cool, but I've never had a problem with spacer tube (that I could tell). The actual piston seems to get more gunked up than that section. I wonder how they machine the inner section to have a larger ID than the ends? Or would they start with a larger tube and essentially "crimp" the ends?
 
I just ordered one as well. I am eager to try this out and see if it helps here in NY during the winter months. I tend to get malfunctions around 800-1000 rounds when its really cold out.
 
I just ordered one as well. I am eager to try this out and see if it helps here in NY during the winter months. I tend to get malfunctions around 800-1000 rounds when its really cold out.

Holy Cow, do you shoot that much in one day? Although I know people do it, I don't purposely let my guns get dirty to the point of malfunction. I will sometimes let a range session or two accumulate, but I don't think I've let my 930 go more than 300-400 round without a cleaning.
 
If you don't mind me asking, what kind of troubles (not to hijack the thread)? The single most helpful thing for me was watching Miculek himself go though the cleaning process on youtube.

More on topic, this looks cool, but I've never had a problem with spacer tube (that I could tell). The actual piston seems to get more gunked up than that section. I wonder how they machine the inner section to have a larger ID than the ends? Or would they start with a larger tube and essentially "crimp" the ends?

I had a couple of different issues. 1st was my gun just seemed to be running really slow. Took a slow motion video with my iPhone and confirmed that it was.


That turned out to be the recoil spring plunger. (not sure of the part name). It's the part that rides in front of the recoil spring and interacts with the tail of the bolt. It had burrs in the rear section of it were the spring had dug into it. I took that out, chucked it up in my drill, and ran it against a file and then some sand paper to round off the back edge.

Once I fixed that I noticed I was also having carrier latch issues. You can see the carrier latch issue in the video, but I initially attributed the problem to the plunger, not the carrier latch until I fixed the 1st problem. So I took that out and polished the tip up and reshaped it a bit so that it releases easier.

If you watch the video that is on OR3GUN's website, they show a short stroke issue, that I have seen before in my friends gun when he was having the same issues as me, and I had one or 2 stuch cases during the whole troubleshooting stage of my issues. My gun likes to run tube dry, and bolt wet. At longer matches, or longer classes with her, I have had the issue of lube going into the barrel, and then into the piston and spacer tube. Mix that with the carbon, dust, and humidity we have in FL and it has caused issues. Wiping down the tube and spacer has fixed the problem in the past, but am hoping that this might stop it from happening.

I am getting ready to do a shotgun match in Feb that has you firing 300ish rounds. Mix of mostly bird, but also some slugs and buckshot. I noticed that the slugs and buckshot tend to gum things up faster.
 
If you watch the video that is on OR3GUN's website, they show a short stroke issue, that I have seen before in my friends gun when he was having the same issues as me, and I had one or 2 stuch cases during the whole troubleshooting stage of my issues. My gun likes to run tube dry, and bolt wet. At longer matches, or longer classes with her, I have had the issue of lube going into the barrel, and then into the piston and spacer tube. Mix that with the carbon, dust, and humidity we have in FL and it has caused issues. Wiping down the tube and spacer has fixed the problem in the past, but am hoping that this might stop it from happening.

I am getting ready to do a shotgun match in Feb that has you firing 300ish rounds. Mix of mostly bird, but also some slugs and buckshot. I noticed that the slugs and buckshot tend to gum things up faster.


The slow motion video on that site really makes me wonder if all of my own stuck shells weren't stuck until they got jammed back in after not ejecting. I've never seen what the bolt cycling looks like when my own have stuck, but knowing I could pull the trigger and get the hammer to fall again each time makes me think it was probably extracting far enough to reset the trigger, but not eject.

It makes sense that sludge build up between the magazine and spacer sleeve would slow cycling and that the design of this part would keep it from happening. I may go ahead and order one this weekend and see if that's all it takes to fix things. It certainly looks more purposeful than what's there now and is cheaper than buying a new barrel or stainless JM Series internals for my SPX.

This is a very good find! I've never seen this information anywhere else in my troubleshooting.

Michael
 
If you have or a friend has an iPhone 5 or 6 you can do slow motion video of your gun shooting. That's how I figured out what my issue was. The iPhone 5 will do 120 frames per second, and the Iphone 6 & 6+ will do 240 fps.
 
I have a lowly 4s. That sounds like another reason to finally upgrade it. That's as good as having a GoPro Hero Black in your phone.
 
I used this on my gun Sunday. I was able to fix my issues before I installed the part. I will say that I was never able to get mine to run on anything lower than 1200fps 3dram eq. before. With this installed I was able to cycle 1145fps 2 3/4dram eq. all day without a single issue. So it deffinately does help. As it gets cold here and there over the next couple of months, that will be the better test of it. So far, I like it.
 
Mine arrived today. Will be testing it this Sunday with 7/8 oz loads (not that I care if they work, just curious).
 
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I wonder at what point the recoil spring will need to be lighter to cycle reliably? I'm happy if just Winchester Universal will finally run in mine. At the price of the high brass Federal stuff, it wouldn't take long to make up the $50 spent for this part. I think I need to have one of these.

Michael
 
Got the spacer today. Will be testing function and testing low fps function shortly

Unit looks like it's very nicely machined.
 
Got to do a pretty good test of it today at a 3 Gun Nation match in Gainesville. It was sprinkling all day. Not enough to make you go home, but just enough to make it suck. I saw 4 other semi's start having issues once they got wet. 2 930's, a Remmy 1100, and a Remmy 11-87. Ended up letting 2 guys on my squad use my gun since I wasn't having any issues. Didn't have a single issue all day for any of us. And we were all using different ammo, from 1145fps all the way up to 1300 fps. Ate everything we fed it today. We likely put 150 rounds through her between us. I'm sold on it, glad I got one.
 
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