r/mossberg

Just picked up my new 590A1 milspec! Not seeing very much of these online with the mlok forend, anyone have light recommendations?

Its an 18 inch barrel, want to go down to 12-14 inches

I've been looking for a reason to start shooting my shockwave again after long neglecting it compared to my stocked scatterguns. I wondered if anyone made a shoulder holster for them. Low and behold I found two main companies. Andrew Costom Leather and Garrity's Gunleather. I went with Garrity's and was not disappointed.

If I were to redo things I would probably go with Andrew Leather due to the weight imbalance between shoulders, but the belt loops help keep things even. I haven't gotten a chance to use it yet due to breaking my left collar bone two days before it came in, but these photos are while I was test fitting it. Hopefully it works gor a nice range to or a "just for fun" setup for local competitions.

Just got my first shotgun, Maverick 88 20in 7+1 . Got myself a sling, 250 rounds of bird shot and some buck for HD. Threw on a esstac 7 round shell card, XS Sight tritium big dot, monstrum mount and polytac X. Now time to practice. Any recommendations that might help?

My first Mossberg. Only had her a week, she’s still pretty clean. 😅 Didn’t realize the build quality was this good. Everything is snick-snack and clicks just right. The trigger is excellent. Lightweight, too. What’s not to love?

Finally!

First of all, my 940 PT SPX is a wonderful gun that is as reliable as a hammer.

But, just like with some of the guns posted here, it will not hold 7 buckshot shells. So I emailed Mossberg CS. A guy named Brandon told me this was a possibility due to variances in shell construction and that this was pointed out in the manual. So I reminded him that most ppl don't read a manual until after they bought the product. But that is that so that's just too bad and I'm SOL. I replied lesson learned for my next shotgun purchase.

Now, in reading here, I have seen the BS they've told some of you who have complained. I've seen excuses like use US ammo only, or some ammo is out of spec. Not one reply to the customer suggested exactly what buckshot load will fit 7 in the mag.

SAAMI publishes the specs for the max dimensions of loaded shotgun ammo. Fold crimped shells max length is 2.40" Roll crimped shells max is 2.45" (about 2 and 7/16) so if your ammo meets these dimensions, like all of mine did, well your shotgun should hold 7 rounds unless Mossberg knowingly designed a magazine tube without considering ammo specs. I shared this information with Brandon and suggested that Mossberg change the ads for the 940 to include a caveat that their gun might only hold 6 shells and that will save them a lot of discussion with customers who drop $1K on a shotgun that doesn't meet advertised numbers.

I read the history of this model line and how Mossberg upgraded / revised it by incorporating lessons learned or complaints form the previous iterations so it baffles me that they did not address this issue that goes back to earlier versions.

Also have an A300 in the box

I am trying to to put my Shockwave back together after cleaning, but I can't get the trigger housing to sit flush. The pin lines up and can be installed without forcing it, but I can't see what is wrong.

Information in the pictures and typed here in the write-up is generally the same. I just wanted it typed out so everything is searchable.

If you would like to see this information presented in a video demonstration with live-fire examples, please use the link at the end of the write-up.

Pic 1:

Title slide with DIY adapters/spacers installed. Keep reading for tube specs.

Pic 2:

Prior to 2016, Mossberg 590 & 590A1 shotguns with an 18.5” barrel had a 5 round solid magazine tube. These guns were “6-shot” capable with a 5+1 capacity (5 rounds in the magazine tube. 1 in the chamber).

Pic 3:

In 2016, Mossberg introduced “7-shot” capable 590 and 590A1 shotguns. These guns still had the 5 round solid magazine tube but now came with a +1 magazine tube extension.

These guns are identical to the pre-2016 guns. Only difference is a mag extension vs cap. Guns came from factory in this configuration.

Pic 4 & 5:

Mossberg 835 shotguns used the same 5-round solid magazine tube that is found on the 590 and 5901 at this time.

Since they used the same magazine tube, the location of the barrel forend lug on the 835, 590, and 590A1 is located in the same place on all these barrels.

So, unless special circumstances apply, Mossberg 835 barrels will fit on these 590 and 590A1 shotguns perfectly.

Pic 6 & 7:

Around 2018, Mossberg “evolves” the 18.5" 590 and 590A1 to have a solid, one piece, 6-round magazine tube. This retains the 6+1 capacity without the need for an extension. This evolution moves the barrel forend lug forward almost two inches meaning that 835 barrels, and older 590 and 590A1 barrels will no longer properly fit on these guns.

Pic 8:

835 barrels, as well as older 590, 590A1 barrels will fit on this new 6-round magazine tube if the gap between the forend lug and the magazine tube cap is filled. That gap can be filled with a 1" diameter steel or aluminum pipe cut to 1-13/16" which is 1.812 inches or 46mm. 1" black iron or galvanized steel pipe can be found at most hardware stores. 1" schedule 40 Aluminum pipe can be found at most metal supply shops or online. 

Pic 9 & 10:

590 and 590A1 shotguns with a barrel length of 20” are “9-shot” capable with an 8+1 capacity. They have a solid, 8-round magazine tube. The barrel forend lugs from an 835 to this variant of a 590 & 590A1 are much farther apart leaving about a 5-inch gap between the barrel forend lug and the magazine tube cap.

Pic 11:

835 barrels will fit on this 8-round magazine tube if the gap between the forend lug and the magazine tube cap is filled. That gap can be filled with a 1" diameter steel or aluminum pipe cut to 5-3/8" which is 5.375 inches or 136.5mm.

1" black iron or galvanized steel pipe can be found at most hardware stores. 1" schedule 40 Aluminum pipe can be found at most metal supply shops or online. 

Pic 12:

Many types of 1" diameter pipe cut to the right length will fill the needed gap. From PVC, to steels, to aluminum.

I don’t recommend PVC. It lacks durability with recoil and degrades under a hot barrel.

Steel is readily available, but can be heavy when using the longer pieces. Aluminum is the best overall option with a great strength to weight ratio.

Pic 13:

Most, if not all Mossberg 835s are chambered for, and designed to use up to 3.5” shells, meaning that it can properly cycle and safely shoot 3.5”, 3” and 2.75” shells.

590 and 590A1s are chambered for, and designed to use up to 3” shells meaning that it can properly cycle and safely shoot 3” and 2.75” shells.

When you put an 835 barrel that is chambered for up to 3.5” shells on a 590/590A1 receiver that was designed to accommodate up to only 3” shells, it will not cycle 3.5” shells properly.

There is a Failure to Feed 99.99% of the time. If the 3.5” shell is forced into the chamber and fired, there is a Failure to Eject 100% of the time.

Pic 14 & 15:

Factory & aftermarket magazine tube caps and extensions have ridges on them that interact with the detent in the barrel forend lug. This keeps your cap/extension from walking loose which keeps your barrel securely attached and in the correct position.

Smooth spacers/adapters don’t interact with the ridges or detents so it doesn’t prevent your cap/extension from walking loose. This may be remedied with lock washers, thread locker, tape, routine tightening etc.

My development on this project stopped here because machining these spacers with ridges stopped being worth my time, energy, and money. Maybe someone else will bring one to market someday, but for now, I’m ok with using a simple 1" steel or aluminum pipe to put any Mossberg 835 barrel on virtually all Mossberg 590 and 59A1s. 

Pic 16:

The Mossberg user manual says, “835® Models are designed for factory loaded 12 gauge 2-3/4”, 3”, and 3-1/2”shotshells. Do not fire slugs of any type (single projectile ammunition) through the overbored 835® Accu-Mag™ barrel. This barrel is designed to shoot lead or steel pellet shot loads only. Use only 835® barrels designated specifically for slug shooting.”

Pic 17:

If you would like to see all of this information presented in a video demonstration with live-fire examples, here is the link to that video:

https://youtu.be/lxFybdC7Ygs?si=kobOpVHeTOzHXYVZ

Thanks!

My first semi auto shotgun.

After some research here, which was sort of a PITA due to Mossberg using the words “Pro” and “Tactical” in many versions of the 940, making many iterations appear in a search, I ended up with the 940 Pro Tactical SPX. I compared it with the A300UP and the M4 before I bought. Couldn’t check out an A300 locally, and the base M4 was a little heavy and a tad long for me. I did not consider the 1301.

Anyway, the 940 PTSPX comes very well equipped compared to other defense oriented shotguns.

-7+1 (in Nevada)
-7 sling points including 4 QD.
-Vang Comp 6 shot card. I have not tested it for shell retention while firing buckshot. OTOH, my two week old Esstacs dropped shells.
-Optic cut for RMSc with plates for RMR, Docter and Leupold included. You lose the rear sight if you mount an RDS.
-Drilled and tapped for scope rails. So if you wish to keep the rear sight you can add a rail and mount your RDS on that.
-Threaded for choke with cylinder choke and wrench included.
-M-LOK slots on the barrel clamp, and on the integrated forend/heatshield at positions 3, 6 and 9 o clock.
-Groove on the magazine tube for the barrel clamp so it will not slide due to recoil or need to be really tight.
-Oversized bolt handle and bolt release/shell release lever. You pull the lever like a soda tab to release the shells but I found that the bolt handle gets in the way a little. NBD tho. It’s not something I have to do fast.
-Ghost ring rear sight and fiber optic front with extra fiber tips included
-Cocking indicator. I didn’t realize how useful this was in a SA shotgun.
-Smooth and flat shell lifter that doesn’t catch my thumb.
-Spacers to adjust LOP

My gun will not manually cycle the aluminum A-Zoom snap caps. The extractor drops it on the lifter. I think it has something do with the weight distribution of the A-Zoom. It cycles the cheap Amazon stuff shown in the pic with no problem.

I took it to the range and put 75 rounds of 1200 fps 1 and 1/18 shot loads along with 10 buckshot shells. The gun ate ‘em up and spat them out with no issues. I was not pulling the trigger as fast as I could but rather controlled pairs. Next trip I’ll run 100 shells.

Cleaning was easy. I just followed the portions of the generic 940 manual that applied to this model. Mossberg also has a video of the Miculeks cleaning a 940 that you can watch but there were no close ups of what they were doing.

My HD situation is simple so if this proves reliable I’m keeping it stock and rotating bedroom corner duties with my 500 pump.

Edit: 8/9. Fired 100 rds of AA 1200 fps 1 and 1/8 oz low brass. . Controlled pairs, no mag dumps. Zero malfunctions. Took the gun apart for cleaning. Everything looks good.

Thank you for reading.

After enjoying the adjustability of my 590A1 with the Magpul stock and thinking back and forth about the Retrogrades I decided to pick up a foreend and stock and try out a thing and go retro. I definitely prefer the corncob foreend, the stock is longer though and obviously not adjustable. Should I have just bought another Mossy?

SOLVED

Hey guys,
I bought an old mossberg 500 and after it arrived, I realized the magazine takes only one shot. I think there is this „limiter“ inside ( don’t know the name)
So Iwanted to open the magazine to check.
Unfortunately this screw is locked af.. I tried oil, heat and force.. nothing.
I noticed this little pin on the side, is this default?! Is it a additional screw lock?!
Would appreciate you help! 🙏

Is there better front sling mount options available and is there replacement caps without holes avail?