Monstrum Laser Sight System with Picatinny Mount for Mossberg 500/590/835/930/Shockwave Series Shotguns

The picatinny mount with the laser seems to work fine. However, of interest to others may be that I have a Mossberg 505 410ga and this mount fit perfectly. Monstrum does not list that model but fear not, it fits. Actually, I suspect it would fit any of the Mossberg 500 series models but I can't prove that. The only real issue was with the battery instructions. The instruction card arrow points to what would be the back of the laser unit and seems to indicate you have to remove the on/off switch unit. You do not. The actual battery compartment is located on the front of the unit, next to the laser lens, and the two CR 1/3 N batteries fit perfectly in that compartment. Just install the batteries negative (-) end first.

I mounted this on a MOSSBERG 510 shotgun .410 ‘Bantam” frame (or Youth model) and was worried about fit as the frame is a little different than the rest. Form, fit and function was exceptional! I was impressed with the Lazer when considering just how cheap everything was! It was more than adequate for the range of a shotgun. The Rail Grove actually worked very well with the “dual front sights” of the Bantam. Later installed a Red Dot sight and it was also a perfect fit.

Parasitic battery drain: I must be one of the unlucky ones. While I see several outstanding reviews, there area few 1 star reviews and I will be adding mine to that category. There is some type of occult parasitic battery drain that results in a dead battery when the gun is put in storage. Like others, the 1st time it happended, I thought it must be my fault? I must have left it on. So second time I was very careful to be certain it was off, after testing it, and yet it still drained in about 2-3 weeks. I then (yet again) put in new batteries, confirmed they worked, but then removed and reinstalled the batteries without testing them. They lasted for months and months and were working fine when I did actually need to take the weapon from the safe and use it. Once tested, however, they too failed (drained out) in 2-3 weeks.Seems the only soultion is to NOT test the batteries, or insert them - but that just means the weapon is NOT ready at a moments notice - which OBTW - is the reason one keeps a weapon.

I takes a bit of effort to remove the mounting screws atop the Mossberg receiver so I was happy to find hex mounting screws along with wrenches for mounting screws and laser horizontal and vertical adjustments.The laser provides a bright small diameter dot on targets all the way to 30 yeards. I didn't check past that distance. Once mounted it passes for a manufacturer supplied part of the shotgun. I also can see the bead sight looking down the recessed center of the picatinny mount. When installing the picatinny mount/laser, make several tightening passes on the 4 hex mounting screws. I recommend this product.

I just mounted this Monstrum Lazer Rail andit was very easy I put the Mossberg 590 S 12 ga.in a vice after mounting the Rail I used the lowerpart of the Rail as a sight and just moved theGreen dot just above the Bore I cant say ( See Photo )enough for Monstrum this worked greatI may never shoot this gun but I it is setclose at 15Ft as you could ever wantI would Buy AgainLarryAdding took out the Original batterys replaced with batterys thatsaid they would last 7 years ( CELEWELL ) thurned on lazer workedfine turned off 3 weeks later they are dead the only differencethat i can see is the original batterys are coverd in plastic holdingthem togather I am going to do that and see if that makes a differenceI will add later to this + Well a month has passed batteries are DeadAgain no help from Manufacture

Note - will update further after I finish installing, but a quick "heads up" for Mossberg Shockwave owners. My .410 Shockwave was *very* reluctant to release the four set screws on top of the action. I got two of them to turn, but the remaining two were so danged stubborn I had to brainstorm some way to get them turned. After stewing over this hurdle for awhile, I just took a tight-fitting gunsmith's screwdriver and tapped on the top with a brass hammer a few times to "drive" the screwdriver into the boogered straight slot. Once removed and my blood pressure came down I realized the slot in two of those screws was so shallow even a great screwdriver couldn't get a grip. Stay tuned - I got them all removed now and will proceed in the morning.Update - Got the rail installed with minimal fuss. Everything lined up perfectly, batteries were installed and laser tested. Out of the box, the laser pointed far right at the side of the firearm's barrel. A few windage adjustments later it aimed directly over the front gold bead sight - good enough for now. Buy with confidence, just know that the OEM screws might give you some heartburn. LOVE this accessory !

Nice mod

At first, I was very impressed, while zeroing it with a shell boresighter in my house (gun unloaded, OF COURSE!). I liked how bright the dot was inside my house, either in complete darkness or fully lit rooms. Then I went to the range, and when I first turned it on, I thought the batteries may be dead. They weren't. Unless the dot was on something dark in the shadows, it is completely invisible in sunlight. That makes it completely useless in the daytime.The next problem, which I discovered immediately and confirmed later at the range, is that the center groove on top of the base is not nearly deep enough. It completely obscures the big dot front sight on my Mossberg Shockwave 20 ga, so that also make the weapon reliant on only the laser, since the laser makes the front sight become completely useless.What it boils down to is that this is a nice accessory for home defense only. It simply does not work in sunlight, and it makes aiming with sights impossible. I needed something to take camping, which will involve being in sunlight, so I have wasted my money on this and will probably remove it. I should have returned it while it was still eligible. Lesson learned - do your research FULLY in advance.