Mossberg Maverick 88 Smooth Bore Slug Gun, by Thomas Christianson

I recently tested the Mossberg Marverick 88 Deer Pump in 12 gauge. It has a 24-inch smooth bore slug barrel with adjustable rifle sights, a three inch chamber, and six shot capacity with 2.75 inch shells.

I found it to be a sturdy, reliable, and reasonably accurate option for hunting deer and other mid-to-large-sized game at slug ranges (50 yards or less). With a manufacturer-suggested retail price of only $245, it offers a highly versatile firearm at an extremely reasonable price.

The Backstory

A couple of decades ago, I was preparing for a hunt on my Uncle’s property, which bordered a state game area. My Uncle’s land was in a shotgun-only hunting zone, so I bought some slugs for my shotgun. It was a 12 gauge semiautomatic Winchester 1400 that I had received from my parents one Christmas many years before. Since the gun had always thrown shot reasonably straight while bird hunting and trap shooting, I assumed that it would throw slugs reasonably straight as well. By making that assumption, I broke a cardinal rule: always test your firearm with the ammo you plan to use before using them for something important.

Dawn several days into the hunt found me hunkered down in the woods watching a game trail about 40 yards away. I saw a good-sized doe approaching from my right along the trail. I had a doe permit, so I shouldered the shotgun, sighted roughly in the center of the doe’s chest, swung the gun gently to the left to allow for the doe’s movement, and squeezed the trigger. The doe jumped up in the air, and then started to run.

Confident that I had a solid hit, I waited a few minutes to give the doe time to lie down and bleed out. Then I walked over to the place where the doe had been walking when I fired. I was surprised to see just a small amount of blood in the new fallen snow. I had expected much more. I followed the doe’s tracks, and noticed that in the course of only about 100 yards the bleeding gradually slowed and then stopped. I continued to track her for about a mile, until I lost her trail among the tracks of a number of other deer. There was no further sign of blood after that first 100 yards or so.

I did not understand how I had just winged the doe from such a short distance. So I put up a large target, paced off 25 yards, and took a shot. The slug hit almost two feet to the left of my point of aim. Further shots gave similar results. The slugs grouped reasonably tightly, but hit consistently about two feet to the left of my point of aim. With no way to adjust the sights, I needed to look for a different slug gun.

I had inherited a Savage 220 from my Grandfather a number of years before. It was a hammerless, single-shot, break-open in 20 gauge. I picked up some 20 gauge slugs, set up a target on a creek bank, and took some shots. The slugs from the 20 gauge were nicely centered in terms of windage, but the elevation was about 6 inches low at 25 yards.

At the same time I tested my Dad’s Stevens Model 940 E. It was a hammered, single-shot, break-open in .410. It put slugs in a nice tight and well-centered group from 25 yards. But I was concerned about whether it had enough oomph to consistently and humanely put a deer down.

My biggest take away from the whole experience was a strong conviction that a slug gun should have adjustable sights. Not too long afterward, my Uncle and Aunt sold their land, and moved into a condo. I didn’t think again about hunting deer with a shotgun for about a decade.

About nine years ago, my wife and I moved into a log home in the woods. I wanted a firearm powerful enough to put down dangerously aggressive animals if necessary, but I wanted to avoid the danger of the projectile carrying a great distance like it would from a rifle. It looked like a shotgun firing slugs would be my best choice.

By that time, I had inherited my Dad’s Browning A5 Magnum in 12 gauge. I decided to look for a slug barrel for that shotgun.

After bidding on several barrels on eBay, I finally won a Hastings Paradox rifled slug barrel for the A5. That barrel is amazing. I can now easily place slugs with rifle-like accuracy out to 50 yards.

The one disadvantage of a rifled shotgun barrel is that it rules out the effective use of buckshot. The rifling typically spins the shot out toward the edges of the pattern, leaving a gaping hole in the middle.

Since I was interested in the possibility of firing both slugs and buckshot from the same barrel, I recently asked Mossberg if I could borrow a Maverick 88 smoothbore slug gun for testing and evaluation. They were kind enough to agree. Not long afterward, I was able to pick up the firearm at my FFL.

Opening the Box

I removed the barrel from the box first. I found it to be a beautifully machined piece of steel with robust-looking sights which gave the impression that they would not quickly be bumped out of zero.

Next came a pack of papers: a Mossberg sticker (“Dependable, Hardworking Firearms Since 1919″), a NSSF Firearm Safety brochure (with 10 basics of safe gun handling elaborated), an invitation to join the NRA, a brochure about safe firearm storage in the home, and the Owner’s Manual.

Then I took the barrel-less action out of the box. One feature that I quickly took note of was the cross-bolt safety at the front of the trigger assembly. This has seemed to me to be the most fitting and proper place for a safety ever since I shot a zillion BBs through my old Crossman 760 as a preteen many decades ago.

As I continued to examine the barrel-less action, I noted that the recoil pad was slightly softer than I anticipated, that the black synthetic stock was attractive by my standards, that the length of pull seemed appropriate for someone my size, and that the action shouldered nicely. The barrel and action were coated with some excess shipping oil, but were not as ridiculously oily as many firearms are straight out of the box.

A final look in the bottom of the box revealed a “Maverick by Mossberg” sticker and a lock.

My next step was to read the entire Owner’s Manual. I highly recommend carefully reading the manual of any new firearm you purchase. You may be surprised at the interesting nuggets of information that you discover.

The manual began with the usual general safety warnings that apply to all firearms. Then I began to run across some items that applied to the Maverick 88 in particular. For example, the manual notes, “Never close the action or pull trigger while barrel is removed as damage could result to the firearm”.

The manual also noted that the shotgun holds either six 2.75 inch shells or five 3 inch shells in the tube magazine and chamber combined. The shotgun is shipped with a dowel in the magazine tube to limit magazine capacity to two shells, in accordance with waterfowl hunting regulations. I removed the dowel for the purposes of my testing.

The manual included directions on how to respond to hangfire and squibs.

The directions for field stripping are more extensive than for any other shotgun that I have used in the past (more on that later). There is a good outline for function testing after reassembly as well.

The Range Session

It was a beautiful day in early spring, with temperatures in the lower 60s. The sun was shining, and a gentle breeze was blowing.

Carrying the shotgun to the range revealed that it was nice and light and easy to carry.

Ammo for testing was somewhat hard to come by. I found a decent supply of Wolf Performance Ammunition, 2 3/4 inch, 1 1/8 ounce rifled slugs.

I put a single round into the chamber and moved the slide forward. I used a Caldwell Lead Sled 3 for my testing to help absorb some of the brutal recoil that 12 gauge slugs produce while firing from a bench rest.

I put the sights on the center of the target, and fired the first shot from 25 yards. It was high and to the left. After adjusting the sights through several preliminary shots, I tried some three shot groups. They were disappointing.

I switched to Remington Slugger, 2 3/4 inch, 1-ounce rifled slugs. The improvement was dramatic, with the holes overlapping one another.

I also tried a number of shots with Winchester Super X sabot slugs. Unsurprisingly, sabot slugs did not work particularly well in a smooth bore barrel.

I tried some more groups with the Remington ammunition with continued good results, and some more groups with the Wolf ammunition with continued poor results.

So in this particular shotgun, the right ammunition can give decent results at slug ranges, while the wrong ammunition can give very unsatisfactory results.

The Lead Sled successfully absorbed most of the recoil, although my cheek started getting sore after a while from contact with the stock


After the range session, I followed the instructions from the Owner’s Manual for field stripping and cleaning the shotgun. I began by removing the barrel. I then pushed out the trigger housing pin, and slid out the trigger housing. Then I removed the cartridge interrupter and the cartridge stop, followed by the bolt slide, the bolt assembly, the elevator, and the action slide assembly. The process was much more extensive than just cleaning the bore, which would be the extent of the cleaning that I would do with many of my shotguns.

I found the internal parts to be extremely oily. I used kerosene as a solvent on each part, and then dried it with a clean patch. I then lightly lubricated each part with CLP, and reassembled the shotgun.

After remounting the barrel, I performed a function test. The shotgun functioned flawlessly.

The more extensive field stripping made me feel much more confident that I was able to adequately clean and lubricate important internal components of the shotgun. I am grateful to Mossburg for this excellent design and clear instructions.


The Maverick 88 Deer Pump in 12 gauge is a robust, versatile, and inexpensive shotgun. The smooth bore barrel obviously could not match the accuracy of a rifled barrel in throwing slugs, but with the right ammunition, it provides more than adequate accuracy at slug ranges for safely and humanely taking medium and large-sized game.

All other things being equal, I think this shotgun would have been a more versatile investment than the Hastings Paradox rifled slug barrel that I bought for my Dad’s Browning A5. But having experienced the astounding accuracy of the Hastings Paradox barrel, I am too addicted to switch to the Maverick 88. If you are not yet addicted, then I recommend the Maverick 88 as a better value and a more versatile tool.


Mossberg was kind enough to loan me a Maverick 88 Deer Pump in 12 gauge for testing and evaluation. I tried not to let their kindness influence my evaluation of the product, and believe that I have succeeded in remaining objective. Caldwell provided me with a sample of their Lead Sled 3 for testing and evaluation for an earlier article. I did not receive any other financial or other inducements to mention any vendor, product, or service in this article.