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What does the Marine Spacer Tube ACTUALLY Do?


We thought we would christen our new sponsor section with some forensic evidence that may help explain what the OR3GUN Marine Spacer Tube does in the environments it was designed for. So, I decided to tear down the Mossberg 930 SPX after an evening of training on the finer details of an MGM Spinner target. This consisted of about 150+ rounds over 3 hours at dusk. This also happened to be at dew point and I wish my safety glasses had as sophisticated a moisture shedding system as my 930 SPX.


Above is what the inside of the forend looked like when I took the gun apart. That's mostly water, which is always and odd find when it wasn't raining.


Hmm, so not just water. There's quite a bit of carbon residue there too.


This gun has one of the original MST prototypes. This one didn't make it to anodizing and has lived in my SPX ever since the first production run. It has seen hundreds, if not thousands of rounds.


Here it is with the barrel removed. You may notice I have a JM magazine tube with the original piston. Tip: Don't throw your SPX in a dump barrel without a magazine tube clamp on.


Look at all that carbon that lives under the piston. Notice how it is still wet, hours after the gun was shot. (The pusher has been returned by the spring without the barrel in place, so the alignment of parts has shifted a bit. You can use the splatter visible under the MST for reference.)


Here's where you can start to see what the MST does with all of that moisture and carbon slop. The magazine tube under the MST is dramatically cleaner than you would otherwise see.


This highlighted section is the contact area that gets 'squeegeed' by the first 'ring' of the Marine Spacer Tube. Notice the splotchy are behind it. This is where the gas pressure starts to exit the holes (along with the filth), leaving some squeegeed splatter behind that the recessed inner section of the tube doesn't make any contact with.


You can now see inside the 'gas end' of the MST where the carbon/moisture splatter that didn't get out the holes and is instead squeegeed into the recessed inner section of the tube.

Rather than all of that slurry building up between your magazine tube and spacer tube where it can slow the cycling of your gun, it gets blasted and squeegeed out of harms way until you get a chance to clean it.

I hope that helps everyone see how the OR3GUN Marine Spacer Tube does its job.

- William

Good to hear. Those had been around for a while and it seemed a shame to destroy them for some finish flaws.
I have had a couple of people ask me what the benefit is. I have explained it a few times. But a match in a Tropical Storm this year showed the what it does. My gun ran without a single malfunction all day. Even being drenched with water, it ran all day. Several went and bought OR3GUN parts after that match
I watched your videos on fitting the gun to the shooter and went straight to your site to order the oval cant adjusting washer do-dad........ but the price scared me !
Any chance you got any bent,mis-aligned,peeling ,cracked, blemished ,etc,etc ones that are discounted ? ;)
Oops. We missed your post about the CDA here. We are currently working on getting them back in stock and will be offering a bare bones version of it. As there are a number of individually machined parts to the full CDA kit it becomes difficult to offer such a specialized part set for less than we already do. If you don't need any of the drop shims or the shorter stock nut it is cheaper.