logiztix

My first thought as well was the chamber needs polished, but with another barrel in play there are other places to look. Is your piston fully returning? Have you taken the rings off and cleaned them separate from the piston? If the piston doesn't return fully it will appear in battery, but the the bolt won't lock and you will get a click when you pull the trigger. How far from battery is it hanging up? Any pictures? Pull the trigger group (2 pins) and run the bolt back and forth to feel for any points that drag. With a high enough round count a rough recoil spring end can be chewing at your plunger, causing it to drag. When you have the trigger group out you can check the condition of the bolt/slide and see any abnormal wear points. Again, pictures. Do you have a speed-loading bracket or side-saddle on the gun (attached through the trigger group pins)? These are common ways to bind up the receiver enough to slow the bolt down and affect cycling.

Unfortunately it isn't quite that easy. Some of the early issues with the 930 were user induced. The SPX was by far the most popular model and nearly everyone added a side-saddle that replaced the trigger pins with a bolt that tightened the receiver up to the trigger group. This would often bind them up into regular malfunction or worse turn them into single-shots as varied levels of torque was applied to an assembly that was supposed to have play in it to keep the receiver the proper factory width. Some speedloader brackets were too tight and did the same thing. This and a bunch of barrels leaving the factory with canted sights set the early reputation of the 930 to less than reliable. The Choate magazine tube extension on the SPX was (and still is) also problematic. They properly used a Nordic on the JM Pro. You can make it worse again by placing a sling bracket between the forearm and magazine extension. The factory follower won't make the jump reliably with one of these installed. The sensitivity of gas system components to dew point and humidity Issues are well documented and addressed by the MST. Issues of general quality control are there, but are typically small things that are easy to address if caught early. That said, they turn into big things if they aren't. Spring burrs that can be fixed with 5 minutes and a Dremel will otherwise start to eat the return spring plunger after a few hundred rounds. It doesn't become a big deal until it starts to score up the interior of the return spring tube and drag the recoil system down. Likewise, a burr on the secondary gas system spring can score the magazine tube and cause the gas system to leak if not addressed quickly. The JM Pro's magazine tube is tougher and less likely to get scored by the spring. These spring burr issues both show signs early and can be avoided completely by breaking the gun down when you get it and giving it the quality control it didn't get. Some guns escaped the factory with rough chambers. Cheap, thin hulled shells that sometimes lock up pumps will hang up in these chambers as well. 2 minutes worth of polishing with the correct materials and the problem is taken care of. Some of them have feed from the tube issues. Brownell's addressed this one years ago in a DIY tutorial: https://www.brownells.com/aspx/learn/learndetail.aspx?lid=15831 The rest comes down to how you make it work specifically for your purposes. They will run loads lighter than many shotguns ever dreamed of with the right parts. They won't do it from the factory because they are designed to survive 3" magnums and springs are supplied appropriately. They can be more difficult in theory to quad load, but in reality the magazine tube is set pretty shallow into the receiver compared to many other guns. The forearm overhang is easy to deal with and most people open the loading port up anyway. You will want to either open up the end of the lifter and open the port a bit forward to keep your thumb. If Mossberg spent a few minutes extra with each gun in assembly line form they would be a lot more consistent out of the box and the only things that would need changed would be done for specific usage. Tearing one down and doing it all to a single gun when it shows up takes about an hour and $75 worth of parts to make it run as reliably as anything out there until it is time to clean it. You WILL have to clean it.

The 930 will run the Universal just fine, AFTER you hone and polish the factory chamber. A 10 minute job if you own the tools. The argument of whether this should be necessary can be countered by whether every shotgun should run the cheapest ammo you can find from the factory. Again, the US built guns have to be built to a price point if they are going to compete with the Turkish imports. My wife's 22" JM Pro will now run 980 FPS, 28 gram cowboy loads, but they also say right on the box not to use in an autoloader. A chamber hone and less than $100 in competition parts. In that tune, however, Prairie Storm has no place in the gun. She takes 2 rounds for a spinner, instead of one. No other platform is asked to run 375 power factor to 1100 power factor without changing something. That doesn't make the gun defective, just not tuned for every task.

When it's hot out, they throw magazine fed guns fits as they deform and don't feed well. They also like a glass smooth chamber or the sharp edge of their fired base tries to hang onto the chamber and plays tug of war with your extractor on the way out. The extractor often wins and the base of the shell loses. Even worse are the Super Speed. These have documented extraxction issues even on pump guns. Same hull, more powder. Worse performance.

A lot of the JM Pro opinions are based on 3 year old experiences before there was any aftermarket support for the gun. Many of the 930s also escaped the factory without a few simple touches (polished chamber, de-burred spring ends) that would have made them far better guns with a matching reputation. An hour with a JM Pro spent by someone that knows what they are doing and $100 worth of competition parts and you will have a gun that I would (and have) put against anything else out there. You do have to keep it maintained. Taking the gas system down after every 300 rounds or so shouldn't be a big deal for anyone reponsible for a gun to accomplish. Like every autoloading shotgun, the JM Pro requires properly manufactured ammo. People that wouldn't feed their Benelli Winchester Universal will complain all day long that a Mossberg won't run it reliably. Feed it the same 1250 FPS Winchester AAs that is suggested for every other shotgun out there when it won't feed 'crap ammo' and you'll find your Mossberg runs a lot better too. Garbage in, garbage out with a gas operated shotgun. Especially if the hulls and bases are thin and hang up on a rough chamber after they expand. There's another consideration that always seems to get ignored in these equipment debates. The Mossberg JM Pro is a US built gun. Americans doing skilled labor demand higher wages than the Turkish, so a bit more American skilled labor may still need done when you first get the gun at the same price point. Mossberg is a US company that employs a lot of US workers and financially supports those fighting to keep our 2nd Amendment rights. Mossberg contributed $150,000 to the NRA's #GunVote initiative alone in 2016. They show up on a lot of prize tables too. They don't simply have a skeleton staff in the US and import guns from countries that hate us when they aren't selling us something. There are plenty of Mossberg 930s out there being used for 3-Gun. As 3-Gun whittles the role of the shotgun away with option targets, 2-Gun, and PCC it doesn't always make sense to spend $2000 on a shotgun and send it to someone to do another $1000 worth of work to it that only applies to a specific sport. When you hit the majors, you might find a $3000 shotgun worth having to make your prize table visit more productive. But, 99% of the 3-Gunners out there aren't at that level and are doing just fine with the JM Pro.

Is there a vent hole in your follower? Feeding wet shells in the rain will otherwise rust out the innards if the moisture gets trapped.

It sounds like you've spent a lot of time working with the Mossberg platform and have had success with it. How much effort do you want to invest in changing everything you already know? If you move to something else you will need to get used to a different safety style and location. You will also need to change your process for chambering a round from the tube, clearing a malfunction or clearing the gun at 'unload and show clear'. Something to consider from a retraining standpoint if you plan to keep the Mossbergs for larger matches.

It is faster if you suck at quad loading. I'm cross dominant, so I use my strong hand on the speedloaders. Much like quad loading, if you nail it you are a YouTube hero, but it doesn't happen every time. The great thing about speedloaders is that you really only have to nail the alignment of the speedloader to the bracket. The rest is just a smooth push and a properly opened loading port. The linked video was after only 2 hours initial practice over a couple weeks. This is with the 6-round loader. http://or3gun.com/Media/Speedloader.MOV I find that I gain time on every load by not having to remove the gun from the shouldered shooting position, park it sideways on a shoulder, roll it over, etc. Quad loading has never panned out for me in time savings from traditional weak hand for anything less than 12 rounds. That doesn't mean quad loading isn't faster, it just isn't for me. We've had rain for all but 4 days so far this year, so my move to Open for this season is being delayed for not having any time behind the new pistol and rifle. I had the shotgun zeroed for slugs after a match and was practicing table starts from an empty gun. After the first couple tries I was able to load 6 rounds and knock over 6 steel at 10 yards in just under 6 seconds. I can't do that quad loading. William

Feel inside the loading port between the magazine tube and roll mark in front of the loading port. That bump needs to go away for smooth loading with speed loaders. It is also a decent plan to open the front of the port enough to allow the occasional slug or specialty load by hand from caddies. You don't need to go crazy, just get the area of the receiver where the shells are binding a bit on the way in and you should be fine. The 6-round loaders are a bit tougher to learn with than the 4-round. They remind me of Kramer steering the fire truck from the back. Practice getting the hooks engaged with the correct angle a lot before practicing the push. It should be able to happen in one smooth motion. If it feels like each round is dragging, your port needs work in the area mentioned above. William

Also, make sure that you are installing it from back to front. Otherwise, recoil forces and loading past it will tend to work it loose.

The poor 930 guys have an option, but it requires a donor Mossberg forearm.

Assuming you took the spring and ring out of the SECONDARY gas system referenced above in this thread and not the primary gas piston and rings that is part of the typical cleaning process detailed in Jerry's video? Getting this back together requires specialty tools. Where are you located?

Riding the safety can also dig a burr into the aluminum block directly under the safety button where it contacts the stamped steel transfer plate, making the problem eventually appear. The only 930 I've personally seen with trigger issues was owned by someone that would regularly forget the safety when the buzzer went off. He would keep his finger smashed on the trigger and try to move the safety, not realizing he was doing it. It was difficult to diagnose originally until I watched him lock it up and saw the internal damage from repeatedly doing it.

Our own 'outlaw' matches have considered adjusting scoring to a new system, based on points that represent the target miss penalty values on a stage. We had a time-plus match with a single long-range stage with two required hits at 300 yards that kicked a couple of otherwise good shooters in the beans. Converting to points with each of the 5 stages worth 100 points didn't especially help. However, adjusting the points of each stage to the penalty value of each miss did. Does that indicate the long range was overvalued? Maybe, unless it means the penalty assigned for a long range miss isn't enough. Maybe it means that each shooter should have gauged the penalty against their talent. Not knowing any of this ahead of the match seems to have the same feel as shooting a group, drawing a circle around it and calling it zeroed. Here was our test approach to stage point determination: Total the miss penalty seconds for every planned target on a stage and convert it to points. Everyone knows it up front and only a change to a stage during setup can alter the point value, regardless of how fast someone shoots it. Example for 3GN scoring values: >100 yard rifle miss = 10 seconds >40 yard slug miss = 7.5 seconds Aerial clay miss = 2.5 seconds Static steel miss = 5 seconds Miss on paper = 2.5 seconds So, a stage with 4 long range rifle hits (40), 2 slug steel (15), 8 poppers (40) and 2 aerial clays (5) is your perfect 100 point stage. A short, all paper hosing stage with 6 cardboard targets requiring 2 hits (or one A) is worth only 30 points. The side effect of this is the potential of revealing how skewed some target penalty values may be with the given scoring system. It could also negate the effect of stage procedures such as making someone carry two bags of potatoes 100 yards while engaging said 6 cardboard targets. At any rate, part of the game is knowing the rules up front and playing it with them in mind for the best personal result. I've shot matches that had my best stage thrown out. I've shot matches where coming in 2nd on long-range was only worth 35% of the points. I've shot matches that had timeouts adjusted between days of shooting. In that case, I could have saved 2 magazines of ammo fruitlessly shooting at a 50 yard pistol plate rack in the dark and would have gladly accepted "you're done" over another 100 seconds of time to waste said ammo. Of course, I could have freely chose not to go to war with it as well.

Related to this, verify that you have eliminated parallax at each yardage you shoot with the 'side focus'. (In focus does not mean parallax free. Perform the bob and weave to check it.) At high magnification, parallax can throw your group all over if you aren't paying attention to it.

I have heard nothing either from 3GN since registration and payment. I talked to someone from the home range a couple weeks ago that indicated the match will have more involvement of the 3GN crew this year, with less input on stage design from the locals. It is my first 3GN Regional, so I don't have a 'normal' level of communication to base my feedback on. I had checked a week or so back on the 3GN website for squadding info and didn't find anything.

What is your twist rate? Some 1:7 barrels don't like 55gr loads. While 2" at 50 yards is pretty bad, if you have a 1:7 barrel, that isn't too far off from what I've seen from some combinations. Lube the heck out of the bolt/carrier and try some different ammo. Factory re-manufactured ammo with random cases isn't a good baseline for function testing. Lots of reports online that are less than stellar for that HPR ammo.

The JM Pro only includes adjustment shims for rise/drop from the factory. If you got the gun used, you may not have received these with the gun or possibly have a Rise or Drop combination already installed. The factory 930 stock has no easy cast, length of pull or pitch adjustments. Before doing anything with the shims if you have them, familiarize yourself with the fitment terminology... Patrick Kelley has written a great article that spells out the basics as they apply to any shotgun: http://www.multigunmedia.com/shotgun-fit.pdf There are also a couple of YouTube videos that do a good job of covering the topic: Most of the stuff you will find is either generic or geared toward the Benelli shotguns that have more adjustments than most. For Mossberg 930 specific help, here is Part 1 and 2 for fitting your Mossberg 930 with factory and/or aftermarket parts: You can get some cast if you need it in a Mossberg 930, but pitch and LOP are going to require power tools. Most people running the 930 with sights on the vent rib can get by with factory drop and possibly cast.

OLD = "Made in the USA" NEW = "Assembled in the USA from domestic and foreign components"

Ive seen it happen a few times. Shooter reloads, goes to flip gun over and hits oversized bolt release. Feeds one onto the lifter and one halfway out of the tube. 930s are the most common i've seen it happen to. The 930 is a different animal and will feed a shell when the bolt release is pushed/pressed in about any direction. The Beretta and Stoeger have to be manipulated just so to make it happen The most popular BA button for the Mossberg 930 can actually eliminate that 'feature' of the gun. Rather than bolting to a drilled/tapped surface of the existing bolt release, it seats over it and creates an over-travel stop to prevent a shell from being accidentally fed from the tube when the release is grabbed on a closed bolt. It moves enough to release the bolt, but not a shell. I rarely see a 3-Gunner empty their shotgun by pushing in their lifter and dumping shells, especially with extended lifters often causing the shells to bind on the way out. The button serving as anything but a bolt release on a shotgun being flipped over for loading on the clock seems to cause more problems than it solves. The Mossberg button from the factory is most likely to double feed shells onto the lifter when pushed straight back toward the stock. This manifests under stress when you grab your oversized bolt handle and start to rack it back, dragging against the bolt release at the same time. When you try to get Mossberg's factory bolt release to perform the shell release 'feature' at all you always get multiples. Best to eliminate the cons of the design, rather than depend on the pros ever working right in the first place. Unless 'right' is trying to dump the entire magazine into your finger that is holding the lifter up.

Another reason to avoid a welded lifter if you can or at least have a slot that allows access to the double feed from below. That accidental, additional shell is a lot easier to get back into the tube if one of those options is available to you.

Excellent write-up! My experience was one of moving the opposite direction, resulting in the same conclusion. I had been running Timneys for years when I was convinced by my peers that I had to have a Geissele SD3G for faster splits. My off-hand and long-range immediately went in the toilet. It wasn't until I went back and forth that I realized that approach shooters probably shouldn't have a SD3G in their rifle. The trigger finger is never in the exact position with a flat trigger, so the varied travel and pull weight combined with a 'surprise break' translates to a lot of long-range frustration. I'll take the defined wall over a surprise any day. Now I am back to being surprised only when I miss at long-range.

Thanks! That's making a lot more sense for the application at hand. The Vortex at first glance seems like the way to go, but it is in MOA and not the mRad that I'm used to thinking in. The Bushnell HDMR looks like a good option as well, but it would take a while for me to develop trust in their quality as past experience with their cheaper lines is part of what has me preferring holdover to dialing. If it holds zero, it looks like I would only have to dial beyond 1000 yards.

That is what I used to think when I saw revolver instructional videos from Jerry. How can the gun changing hands twice be faster than using your weak hand to reload the gun? He somehow makes it work. I have many first round 1000 yard hits with my 2nd focal plane holdover method and I've put others behind the same gun with the same result. It works, but I'll agree it isn't the best plan on paper. I'm open to suggestions for the 6.5, but for this gun I'm again placing speed of getting hits on presented target over absolute accuracy. If I could efficiently get out to 1000+ yards with a first focal plane reticle I would be thrilled. I would be especially thrilled if it was in the ballpark of the Mark 4's price. What FFP (or fixed magnification) scopes with the Horus have 10 Mil+ worth of drop in the reticle? I'm already finding that the Mark 4 isn't long for this gun. It's a great scope, but very slow for me on the clock. The idea of the 6.5 Creedmoor in an AR platform was 1 MOA accuracy with quick transitions between targets at distance and less time spent on wind calls. The finicky parallax adjustment and the narrow eye relief on the Mark 4 is slowing me down at 20X (where the Mil-Dot is accurate) and I'm finding myself actually preferring it at half power (which I have verified is actually at the 12X mark on this scope, oddly enough). Every 1000 yard hit I have ever made has been at 6X. Every other Mil-Dot I have in use is accurate for ranging at 12X. I shoot Limited, so anything more than 1X always feels like a bonus. I could probably handle a fixed magnification scope with a Horus reticle if it got me out to the limit of the rifle with holdover.

I never see it mentioned in any of the 'lists', but the Olympic Arms K9-GL I have runs great. It was a special order with a flat-top upper and free-float forend, so I imagine the standard carry handle version they normally sell would have minimal use in PCC. It digests any 9mm I've tried to feed it, is plenty accurate for the task and takes Glock mags. The factory trigger is pretty good as well. Having been in the PCC game for years (with nowhere to play it), I have owned both a Beretta CX-4 Storm and a Kel-Tec SUB 2000. I never reversed the innards of the Beretta, but as a lefty, the K9-GL is WAY less gas and brass in the face than either of the other platforms. I image the newer offerings from other companies are more tailored to 3-Gun, but it is another option if you can track one down.