Customer Reviews for Bullpup Unlimited Mossberg 500/590 Conversion Kit

Dec 2022. Many more positive than negative. Heavy and not cheap. Hate the A2 grip so I ground off the finger notch. But, I finally got my Mossberg bullpup having regretfully missed out on the factory one since the 1980's. Yeah, I'm that old. Takes some thought and patience to put together. But smooth, cause the donor was well worn in and smooth. Swings well in room to room. Controls well thought out. My choice over buying a Kel TEC. Doesn't feel toyish and I felt was worth the price.

Bought this conversation kit for my mosberg 500. The kit was a perfect fit and I’m extremely happy with it. It turned my full length shotgun into a tactical weapon you can use in home defense and turn around in a closet.

This kit turned my Mossberg 500 into my favorite gun to shoot. What a blast! (Pun intended) The ergos are fantastic and the trigger feels great even though you’re pulling on a remote trigger that’s linked to the factory one buried in the stock. The recoil is minimized greatly and this thing gets TONS of attention at the range. I put some cheap flip up sights on it as well as a cheap light. So much fun awaits anyone who does this fully reversible conversion. If you’re on the fence, just do it!

This was the 1st purchase I made from Buds Gun Shop. Since then I have bought a number of Savage rifles from them and have never been disappointed. This kit went together quick and easily and does what I was looking for. Would highly recommend it if your looking to build that special little pump.

I converted my Mossberg 500 and it is like I got a new gun. It sets good on the shoulder for most people although my wife felt it was a little long for her small frame. The function and mounting is solid which was a concern before I did the conversion. The rail space is amazing and everything fits without any special modification. I will look forward to shooting trap with it to really see how it runs. Great product and Buds delivered fast!

Awesome Bullpup kit. Easy to convert. Shotgun is much more useful for home defense now.

This bullpup stock is Fantastic. It's short plus all the weight is back toward the shoulder which makes it so much easier to hold and maneuver. I can easily switch from between both my 18.5" security barrel and my 28" Ribbed Accu-choke hunting barrel. The only problem I ran into was the forearm slide tube was 1/8" longer than both my mossberg factory forend and also my CHOATE Machine & Tool, Inc forend which were both the exact same length. The slide tube nut would only just barely thread on and bottomed out not being able to sock down as far as with either the factory or CHOATE forends. I trimmed 1/8" off the front of the Bullpup Unlimited forearm slide tube making it the exact same length as the other two forends which corrected the problem and the nut was then able to tighten down as far as on the other two forends.

I have had this bullpup conversion on my Mossberg 500 12ga with an 18.5 inch barrel for two years now. The instructions were clear, the kit installed very easily, and the gun functions flawlessly in the stock. The controls on the kit work the controls on the gun very well. The trigger is not bad for a bullpup. I really enjoy the extra large and soft buttstock pad, as it takes a lot of the kick out of the gun. The shorter gun tucks into your body nicely and I like the balance of the weapon. I currently have Magpul pop up sights on the gun and they work fine. I had to file down the front sight pin to just a nub to get the point of aim up high enough and correct at 15 yards. The gun kit requires some time and effort to disassemble it to clean the gun, as there are a lot of screws holding it all together, but it’s not difficult. Loading the gun under stress is more difficult and will require practice because the loading gate is near your armpit and out of your line of sight. The kit works well for both right handed and left handed shooters. The only issue I have with the kit is the forend release button on the Mossberg 500 is designed to be easily actuated with your index finger while gripping a traditional shotgun stock. Any pistol grip conversion to this gun means your have to let go of the grip and contort your hand to push the button to close the action on the first round. Be careful. The rear sight is much closer to your face than on a traditional shotgun setup so you have to take care to hold the gun firmly and watch your eye relief distance or you will go home from the range with a cut eyebrow. This stock renders the gun useless for trap and skeet shooting but an 18.5 inch barrel isn’t ideal for that anyway. If you want a super cool looking bullpup shotgun that always draws positive attention at the range, this kit works very well with this shotgun. If you shoot clays or want to maximize your shotgun as a tactical weapon, I would leave the gun in a more classic stock.

This conversion allows shorter and quicker smoother loading, firing and ejecting brass and plastic like nothing of the original product.

After disassembling my Mossberg Maverick 88, and reading through ALL of the instructions included with this kit prior to assembly, this kit went together in less than an hour. All tools and screws were included. I recommend sorting the different screw types and lengths prior to assembly. This is a great and simple kit for the price.

I bought two one Mossberg 500 for myself and one Remington 870 for a friend real easy to put together and the fast shipping was great

As a 18 year veteran Police Officer, I have found that being 5' 8" and a stocky 240 lbs it has always been difficult to carry my standard length Mossberg 590 A-1 long gun in the field dragging it in and out of the cruiser without the concerns of knocking the dam thing into door jambs or dragging it against the walls at the worst possible times. However I have recently found several You-Tube videos pertaining to a very unique bullpup conversion kit manufactured in Kentucky, USA by Bullpup Unlimited, the videos demonstrate how to convert your existing Remington or Mossberg 12 Ga. factory length shotgun into a much shorter bullpup without reducing the overall barrel length. With the addition of a AR style grip, selector safety, adjustable sling mounts, picatinny rails for optics and other accessories I knew this was a product worth looking into. After I placed my order with Bud's.com they were super fast with my shipping email updates keeping me posted on delivery times and it arrived on time and in perfect condition. If you are not the above average gunsmith, I would strongly advise you to read the simple step by step instruction manual and follow it to the letter depending on the weapon system you are using and of course always start with a clean well lit environment free of distractions for about 2 / 3 hours using a clean, oiled, function tested, completely empty weapon keeping your 12 Ga. ammo separated in another room before you begin to avoid any possibility of accidents. Once your old shotgun is completely reborn into a 12 Ga. conversion bullpup you may just find yourself enjoying a whole new level of love for shooting 12 Ga loads. (even slugs) I would highly recommend this Bullpup Unlimited conversion kit for your ultimate 12 Ga. home defense weapon that has virtually endless "practical / tactical" possibilities. P.S. Looking forward to the Next Gen BU-II version for the Mossberg 590-M (Magazine fed)

NOT BAD FOR WHAT IT IS I purchased this bullpup conversion kit because I wanted to see what it was like to have a bullpup system without the bullpup price-tag. Assembly was pretty straight forward, after following a youtube video I ended up having thing assembled in less than an hour. The firearm felt solid in the kit and nothing feeling "loose". There were two things I thought could use improvement. The trigger in the kit comes vertically sliced in half with one half sitting about 1/4in further forward then the other. It was designed this way on purpose to act as a trigger safety, problem I found with this was that it was uncomfortable and overall unnecessary since the kit already gives you an AR style safety on the side as well. My simple solution was to take the two trigger pieces and wrap them together with a SMALL amount of electrical tape to keep even with each other followed by a heat gun and some black shrink tubing. It made the trigger feel like a single piece that felt better to the touch. The other problem I found was since the kit holds the firearm together with so many screws it can be a pain in the ass to take apart to clean the firearm. It wasn't a big deal but time-consuming since after you finally got the kit off you then had to clean the firearm, then reassemble everything back together and put back into the kit. All-in-all I found it to be a good purchase. If you already have a Mossberg 500 and your looking to have a bullpup without paying bullpup price then this kit will do the job nicely.

I wanted a bullpup type shotgun for home defense. I had a Mossberg 500 and decided to add the Bullpup kit to it. The Bullpup kit is easy to install and fully functional however in hind sight not the best solution for my intended use. Looking back on this purchase I would have been ahead selling or trading my Mossberg for one of the factory built bullpup type shotguns that are available from other manufacturers. The combined price of a Mossberg pump action shotgun and the Bullpup kit is approaching the price of factory made bullpup shotguns which have double the magazine capacity. For me this is a case of live and learn.

Hey Team Bud's! First off, your customer service is boss, just like the Bullpups Unlimited converson kit for the ole Mossberg 500! We had no issue with the install. For the price ,you can be a Colonial Space Marine at home or at the range. The design is great for home defense making it easy to preform sweeps , with the added padding ,recoil is nicer. I'm getting to old to practice with buckshot or slugs , so overall , I got what i wanted and paid for ,without breaking the bank. If you are in the market to spice up the life of an old friend ,JUST DOOO EET! Take care, MERICA!

I'm very impressed with this bullpup kit. It's a very well thought out design that installs easily. Everything lined up perfectly with no fitting problems. My trigger is now heavier and mushier but still very useable. My shotgun is now much shorter and functions flawlessly.

The Conversion Kit made my cheap Mossberg Maverick 88 into the best looking tactical shotgun! This kit is for budget wise gun owners who wants the tactical shotgun such as the Kel-Tec KSG or DP-12. Even though the kit will not alter the limited magazine tube; the pro over weighs the con when it deals with reduces length of gun (California Legal Length 18-20 inch barrel), best choice for home defense, and perfect fit for gun owners who has short arm length between the stock and trigger placement.

PROS: -Reduces length of gun while still being legal overall length and barrel length. -AR style controls. -More options to add mods to the kit(dot sight, grip, etc.) -Really tames the recoil. CONS: -Screws can be difficult to insert during installation. -Slide release placement feels very awkward. -Hate the screw that is used in the pistol grip. It requires a very long hex screwdriver(which not many people like myself own), and should've used a flathead or crosshead screw. -Can take a very long time to clean unless you have a bore snake. -Buttpad feels very insecure, as only 2 pins(1 on each side) secure it.

shot gun looks way cool, freaking expensive in my opinion for what you get,i mean 150 to 200 is acceptable but 300--- ugh ,much heaver now too .cycling is not super smooth ,trigger a little heavy ,again its a bull pup.defiantly upgrade the rear grip to something better because this one sucks.like the rails though.butt pad is very soft but is wobbly because of how it attaches we shall see how that holds up over time .did not like the fact buds used usps instead of parcel service ,i hate usps ,any way thanks out of all that still like it

received bullpup Mossberg 500 conversion kit in about a week took about an hour to install on shotgun pretty basic . put about 50 shells thru it not one problem will update if there is one also with pad on the new stock it makes the gun fun to shoot didn't think I would say that about a 12g shotgun so far it has been an expected experience will order from buds again

More than what I expected! Bud's shipped extremely fast and I received my Bullpup conversion in excellent condition. Thanks Buds!

The kit installed perfectly. I agree with all of the other positive reviews. Want a bullpup? Want to do it yourself? Then this kit is right up your alley. It's a bit pricey, so if you are satisfied with your Mossberg, this kit is not for you.

easy to assemble, no alterations necessary, works great and looks cool. turns my shotgun into my favorite home defense tool. only downside due to the nature of the product is cleaning the shotgun, since everything has to be taken apart again.

Installed this on my 20" Mossberg 500. Installation took less than an hour and the fit was perfect without any problems. Overall length of the bullpup shotgun came to about 32" and seems to balance weight toward the rear when shouldered. Installed some Magpul sights and shot the gun using some Federal 2 3/4 low-recoil slugs at an indoor range at about 25 yds. The slugs were very accurate without any adjustment to the sights whatsoever. I absolutely love the handling of this bullpup over the stock configuration. The AR style grip and safety is an added plus. I did install a Hougue over-molded rubber AR gris to give better handling. Overall impressions from people who also shot the firearm were very favorable. Cycling the action was smooth with positive ejection of shells slightly forward of the user (designed for the left-handed shooters). This kit brought new life to my Mossberg 500 and is possibly the best conversion to date.

Great Kit! i really like my Mossberg 500 now. great construction, feels strong I have no concerns on the workmanship of this kit. Thanks for offering it at a great price.