mpom Posted November 18, 2014 Share Posted November 18, 2014 Thanks for the background update, suspected you tried to modify the oem part first. Since I am running a JM with a plated mag tube which unlike the SPX is not prone to rust, will hold off on your improvedesktop part for now, but will keep it in mind. Link to comment Share on other sites More sharing options...
logiztix Posted November 18, 2014 Share Posted November 18, 2014 The rust was really a secondary problem. The effect of the water in the spacer tube in slowing the cycling of the gas system is the primary problem and what leads to FTEs. If you have the plated parts of the JM Pro, the rust itself won't be an issue. In a way, the JM Pro parts betray the underlying problem by masking the most obvious evidence that the part is trapping moisture. In the right weather conditions the gas system will still fail due to the moisture simply being there, mixing with the carbon and being forced into the spacer tube to create more and more hydraulic friction. It's the hydraulic friction we're primarily battling, with eliminating the rust being a by-product. Admittedly, it is a tough sell. It's easy to sell a solution to a problem someone knows they have. It becomes much tougher to sell a solution to a problem someone may or may not have encountered and known what the cause was. We had just figured out how completely NOT random our malfunctions were once we factored in the weather at the time. The M3GI practice sessions sealed it. There was no other reason for multiples to go down at once. Breaking them down and finding water was the common denominator. Once we had solved the problem we went back through hat cam video from matches and every time we would catch a malfunction we were more and more convinced we had figured it out. It was always on match days where the fog was so thick that long-range stages were cancelled and the 930 couldn't make it through a stage without failure. Link to comment Share on other sites More sharing options...
mpom Posted November 19, 2014 Share Posted November 19, 2014 Sounds like Mossberg ought to either pay you a royalty or offer to buy the patent, and start incorporating your mod into their production line Link to comment Share on other sites More sharing options...
IntenseImage Posted November 19, 2014 Share Posted November 19, 2014 For $50, it's cheap insurance ... got one on order Link to comment Share on other sites More sharing options...
Tuflehundon Posted November 19, 2014 Share Posted November 19, 2014 For $50, it's cheap insurance ... got one on order That was kinda my thought. With all the other issues I had and fixed, this was cheap insurance that I wouldn't have another issue. Link to comment Share on other sites More sharing options...
Tuflehundon Posted November 23, 2014 Share Posted November 23, 2014 Well I'm sold on the Marine spacer. Shot a local 3Gun Nation match today. It sprinkled all day. Not enough to make you want to leave, but just enough to piss you off. Saw 4 gas operated semis have issues running, 2 930's, 2 Remington's (1100 & an 11-87). 2 other shooters on my squad ended up using mine when there gun had issues. Even with 3 of us shooting it in the rain, not a single hick up all day. And all 3 of us were using different ammo. Link to comment Share on other sites More sharing options...
robport Posted November 23, 2014 Share Posted November 23, 2014 Well now I've been sucked into this sport too. I bought a JM pro for my Christmas and Birthday present and shot my first match yesterday. It made it through the first two courses of fire, but choked about 10 rounds into the third. When I say choked, I meant locked up and wouldn't hand cycle. Looked like there was at least a round and a spent one were in the chamber. The match director, who happens to be a gunsmith, cleared it for me (I treated it with much more fear of damage then he did...lol). He used a significant amount of force and his foot. I tried it again on the fourth course of fire and it did it again after about another 10 rounds. The match director grabbed it again and cleared it, then handed it back to me and told me I might as well finish the stage. It did about 15 or 20 rounds flawlessly after that. Is this a common recognizable problem? It sure didn't look like the ones in the preceding videos. I couldn't clear it myself, but I remember having about two or three of those too. Could it simply be a piston problem? I followed the Jerry M. disassembly video and the piston rings were aligned. It looked like it had left a carbon arrow shaped deposit on the feed tube. Link to comment Share on other sites More sharing options...
rtp Posted November 24, 2014 Share Posted November 24, 2014 Well now I've been sucked into this sport too. I bought a JM pro for my Christmas and Birthday present and shot my first match yesterday. It made it through the first two courses of fire, but choked about 10 rounds into the third. When I say choked, I meant locked up and wouldn't hand cycle. Looked like there was at least a round and a spent one were in the chamber. The match director, who happens to be a gunsmith, cleared it for me (I treated it with much more fear of damage then he did...lol). He used a significant amount of force and his foot. I tried it again on the fourth course of fire and it did it again after about another 10 rounds. The match director grabbed it again and cleared it, then handed it back to me and told me I might as well finish the stage. It did about 15 or 20 rounds flawlessly after that. Is this a common recognizable problem? It sure didn't look like the ones in the preceding videos. I couldn't clear it myself, but I remember having about two or three of those too. Could it simply be a piston problem? I followed the Jerry M. disassembly video and the piston rings were aligned. It looked like it had left a carbon arrow shaped deposit on the feed tube. Have to ask the obvious - did you clean the gun fully after purchase? Check the big Mossberg 930 thread - many of us posted various tidbits to check and/or correct on the 930. Mine's still running strong, ran in the rain today.. Link to comment Share on other sites More sharing options...
stinsonbeach Posted November 24, 2014 Share Posted November 24, 2014 Ok, ok . . . I've solved all my problems w/ my JM Pro but I've been convinced to buy one of the Marine Spacers. As many have said, "...cheap insurance..." Link to comment Share on other sites More sharing options...
mpom Posted November 24, 2014 Share Posted November 24, 2014 I like the concept, but its NOT so cheap (unless I am so cheap). However, the wife is looking for stuff to give me so will suggest this. Besides, why not support a forum member? Link to comment Share on other sites More sharing options...
Tuflehundon Posted November 24, 2014 Share Posted November 24, 2014 I like the concept, but its NOT so cheap (unless I am so cheap). However, the wife is looking for stuff to give me so will suggest this. Besides, why not support a forum member? When you are running a rifle / optic combo valued at $3000+, and pistols around $2000, a $50 part is cheap. Link to comment Share on other sites More sharing options...
stinsonbeach Posted November 24, 2014 Share Posted November 24, 2014 I like the concept, but its NOT so cheap (unless I am so cheap). However, the wife is looking for stuff to give me so will suggest this. Besides, why not support a forum member? When you are running a rifle / optic combo valued at $3000+, and pistols around $2000, a $50 part is cheap. EGGxACTLY!!! Link to comment Share on other sites More sharing options...
mpom Posted November 24, 2014 Share Posted November 24, 2014 Damn, you guys are costing me money While I never had the issues this solves, I suppose it worth the peace of mind, plus it sure is cool looking! Link to comment Share on other sites More sharing options...
stinsonbeach Posted November 25, 2014 Share Posted November 25, 2014 (edited) . . . as I said above, I've solved all my JM Pro issues, BUT if the SHTF this is one of my "go to" guns & listening to all the comments, I sure don't want it to go "click" at the wrong time!!! I know a lot of folks out there'll be saying, "...pump...", but 8+1+1 as fast as you can pull the trigger w/ 4 Buck allows you to walk thru walls & lay down as much punch as a machine gun!!! $50 bucks'll help me sleep better! Ordered it yesterday & it shipped within a couple of hours! Edited November 25, 2014 by stinsonbeach Link to comment Share on other sites More sharing options...
logiztix Posted November 25, 2014 Share Posted November 25, 2014 Tuflehundon, the positive feedback on the part is great to hear. Your experience mirrors the matches we've been to where the gas guns started to fail as soon as the mist began. I know exactly the kind of rain you're talking about. I think I've shot half of my 2014 3-Gun matches in it. Glad to hear your 930 was the last one standing. One of the first 3-Gun matches I shot (over 3 years ago) with my original 930 SPX was shot under similar conditions with 2 other 930s having problems the same morning. I hammered the bolt back so hard by hand that I ripped the aluminum lip off the shell with the extractor. I have the hat cam video somewhere of the RO pulling out a pocket knife so I could pull the stuck shell on the clock. I got bit by the shell stop correcting the double feed I created and ripped my thumb open. The RO's ending command was "if you're finished bleeding all over your shotgun, unload and show clear". Later in the match he politely asked if I had considered getting a different shotgun. He mentioned the FN SLP something or other. So naturally, I bought a second 930 with a 24" barrel. I ran into the RO running a stage at M3GI this summer and he asked if I had gotten a different shotgun yet. I laughed and told him I was working on it. My original SPX is what I used at M3GI and it ran both nights flawlessly with the original MST prototype. Link to comment Share on other sites More sharing options...
robport Posted November 26, 2014 Share Posted November 26, 2014 I had cleaned it, but hadn't taken the piston apart before I shot it the first time. The piston rings were lined up in the same direction. It left a carbon arrow-shaped mark on the feed tube, which is why I suspected the rings when I saw it. I don't know if that did it for sure, but I went out yesterday and pumped 15 rounds through it, as fast as I could fire and reload and it performed flawlessly for that (it didn't fail the first time until about 65 rounds into the match). Taking the piston out again, the very light deposit was evenly spread around the feed tube (not concentrated in one place and very heavy (I wish I had taken a picture of it). I don't know if it's fixed, but I'm sure I found something that definitely wasn't right. Link to comment Share on other sites More sharing options...
logiztix Posted November 29, 2014 Share Posted November 29, 2014 Where on the magazine tube you are seeing a pattern of carbon and what direction is the 'arrow' travelling? The 930 has a dual gas system. On lighter loads, the secondary 'overflow' system (which you can see further down-barrel of the piston as a heavy spring with a single gas ring) will move very little in cycling lower powered loads. It is not uncommon to see gas leakage past the single ring on that side of the gas system. Heavier loads (and resulting excess gas) will move this ring to a much greater degree and will result in faint scratches that rotate around the magazine tube a bit more with every round shot. It is easy to lose track of exactly where each system rides on the magazine tube when the gun is torn down for cleaning unless you have burned a good reference mark from the two gas ports. It sounds like you have it running, but hopefully that gives you more to look for if it happens again. Link to comment Share on other sites More sharing options...
stinsonbeach Posted December 2, 2014 Share Posted December 2, 2014 (edited) Update: Got my MST a few days ago - remember now, I had solved all my JM 930 issues already but decided that the Marine Spacer was "cheap insurance." I pulled my 22" apart & believe me, I don't know how it was still running. Under the stock spacer tube was so much crud I should have taken a picture. I've put so many rounds thru it w/o cleaning that I've lost count. Anywayzzz, cleaned it & put in the MS. Now to the range - my back deck . . . Put 8+1+1 of light-load 980 fps #7.5's thru it as fast as I can pull the trigger. Did it 3x. Not a hiccup! ...& it was much faster than before. NO chance to out-run it! Right after I hit "POST" here, I'm going to go online & get another for my SPX! As stated earlier x many: "...cheap insurance..."!!! ps just put in my order for another MST - if you do it today you get free shipping! pss I'm in no way connected to the MST people - I have NO horse in this race!!! Edited December 2, 2014 by stinsonbeach Link to comment Share on other sites More sharing options...
Boxerglocker Posted December 4, 2014 Share Posted December 4, 2014 (edited) I had earlier issues with my JM Pro when I very first got it and figured out what many have stated here. Cleaning was the key to reliability. I ended up getting into a routine of scrubbing the outside of the mag tube with 00 steel wool and a non petroleum cleaning solution with a little water, wiping it dry (lube only with a little dry silicone wipe). I took a page from Jerry's youtube video in cleaning the 930 and got a set of these 18 inch handle bronze bristle bottle brushes. They make cleaning the inside of the spacer, piston bores so much more efficient and easier. I run Winchester super target loads no issues. As for opening up the loading port here is what I did myself. I load deuces primarily but quads are not a issue either. Edited December 5, 2014 by Boxerglocker Link to comment Share on other sites More sharing options...
Mbiker101 Posted December 4, 2014 Share Posted December 4, 2014 Wow boxer, that loading port looks fantastic!!! What is your technique? Link to comment Share on other sites More sharing options...
Shooter116 Posted December 4, 2014 Share Posted December 4, 2014 (edited) I would sell that POS to anyone that will buy it and buy a Benelli M2 and never worry about having an issue again. One of the guys I shoot with just had his first malfunction with his M2 at Fallen Brethren. He hadn't cleaned it in over 6K rounds. That is reliability. Edited December 4, 2014 by Shooter116 Link to comment Share on other sites More sharing options...
HeyChris Posted December 4, 2014 Share Posted December 4, 2014 The JM Pro is a great shooter, especially if you listen to Jerry's recommendations on cleaning. I clean all of my weapons after every match and have never had any problems with the shotgun. Agreed, nice work on the port. Link to comment Share on other sites More sharing options...
stinsonbeach Posted December 4, 2014 Share Posted December 4, 2014 (edited) VERY nice work on the port! How'd you do it? ps ordered the MST on 12/02. Been away today & just got to the mailbox. MST delivered! How do they do that? Tues to Thurs??? Edited December 4, 2014 by stinsonbeach Link to comment Share on other sites More sharing options...
Tuflehundon Posted December 5, 2014 Share Posted December 5, 2014 VERY nice work on the port! How'd you do it? ps ordered the MST on 12/02. Been away today & just got to the mailbox. MST delivered! How do they do that? Tues to Thurs??? Just takes a file, dremel tool with sanding disks, some sand paper to finish up with and some patience. Start with a flat file and slowly take the sides down, then use a rounded file on the front section. Dremel will help with the rounded front area but take a little at a time. once you get it were you want use sand paper to polish it up. Search YouTube, there are a few videos out there. Link to comment Share on other sites More sharing options...
Boxerglocker Posted December 5, 2014 Share Posted December 5, 2014 Wow boxer, that loading port looks fantastic!!! What is your technique? Thank you, I'm a aircraft technician by trade and familiar with metal work so it was pretty easy. I used a selection of files, pneumatic die grinder, dremel, sand paper, polish... it just takes a little time and patience. Link to comment Share on other sites More sharing options...
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