930 Gas Port Shooting Slugs Issue

[Misery930]

Pretty much every time I've fired slugs or really anything but target loads for the last few months, I've noticed that my gas ports seem to be taking a lot of abuse. It wasn't always like this so I'm not sure what the issue is. I was shooting Winchester super x slugs and it was so bad I had to refinish my barrel. It burnt it so bad that it was like a small explosion going off around my gas ports after every shot. Does anyone else have this problem? I have cleaned the gas ports with mascara brushes so there's no obstruction and I cleaned the piston pretty recently too. Any suggestions?

 

[LTB45]

So you are getting excessive fouling and think its the gun?

Its the dirty burning ammo.

I reload and I can honestly say some powders burn much cleaner than others.
I reload a ton of Red Dot for my Trap loads. The stuff is FILTHY, but it gets the job done.
Clays is another powder I have used. Almost like it cleans the gun for you.

 

[Misery930]

I've shot Winchester slugs forever and these past few months were the first time I had problems with it. It's basically blowing up my gun when I shoot it, it's hard to even see the target after I fire because of the huge cloud of smoke the rounds make and it doesn't even feed well. I've had malfunctions with this crap just doing combat reloads. It's obviously a problem with the ammo but it's smoking under the handguard, burning the barrel even when I shoot buckshot and slugs of other brands. That's why I'm wondering if there's something wrong with the gun. I've had the shotgun for probably 5 years and this is something that has just recently started happening.

 

[Rob72]

I would clean and degrease your barrel, ports and piston, be sure to use something like Gunscrubber or Wallyworld Brake/carb cleaner to get the carbon off. Spray them down with dry lube (WD-40s dry lube is reasonable and accessible). If you still have the issue, its all ammo. If not, its holding lube in carbon buildup.

 

[OR3GUN]

If the round is powerful enough you should expect some smoke from between the top of the forearm and barrel toward the front, as this is where your secondary gas system lives. This system is venting excess gas pressure on hot loads.

It still sounds like sketchy ammunition, but the locations you are seeing smoke from it are not abnormal. When you do you do get in there to clean it well, look for signs of the secondary gas system cycling properly. Primarily, ensure there is no scoring of the magazine tube forward of the primary system as this can cause the secondary to leak with ALL loads, reducing the gas available to properly cycle the gun.

William

http://www.OR3GUN.com

 

[Misery930]

My magazine tube is a mess around the gas ports. It burned the finish off a while ago so I sanded it and take it apart every week or so to oil and watch for rust. I would reblue it but there's no point because it would just be ruined again as soon as I fire it. What does this mean?

 

[OR3GUN]

That is likely the root of your issues. The magazine tube serves as half of your gas system's sealing surface, with the actual barrel's cylinder serving as the other half. When the tube gets scored up it is usually due to the secondary gas system running a steady diet of heavy, hot loads. The mechanical cause is usually a spring burr or sharp edge on the secondary system's ring that chews into the softer magazine tube surface. The common home-brew approach to trying to fix this is to sand it down and polish it up, which only makes the entire magazine tube undersized and doesn't do much to fix the deep scoring. Gas leaks from around the area, much smoke pours from around the forearm and little gas remains to cycle the gun. If this area is left un-blued and allowed to rust and pit the situation becomes worse.

Unfortunately, it is time for a new magazine tube. It is a good idea to upgrade to the version from the JM Pro while you're are it. The Boron Nitride finish is tougher than the blued steel and will not rust and pit. Our Marine Spacer Tube helps minimize the rusting/pitting on non JM tubes, but it is always worth the magazine tube upgrade if you are in there anyway. Also, for some reason the 930 likes loads to be fed in a variety fashion. A steady diet of 100 hot slugs will wipe out a magazine tube, while 100 hot slugs fed at random within 500 bird shot will show no ill effects.

If you need a part number for the magazine tube, I can dig one up for you. Otherwise, give Mossberg a call and tell them you need the magazine tube for a 930 JM Pro.

William

http://www.OR3GUN.com

 

[oli700]

now thats service !