The Future Is Flexible

Especially with the new Mossberg
FLEX 500 12-gauge shotgun

Good gun, good ammunition, good camouflage and patience spell turkey. This tom was
no match for the new Mossberg FLEX 500 pump-action shotgun.

I was always curious about European arms makers who offered one rifle receiver and interchangeable barrels in a dozen different calibers. Knowing a few sportsmen who bought into the concept, I observed that, most of the time, their one receiver was mated with one favorite caliber barrel while the other barrels languished, gathering dust in the gun safe.

and, depending upon the mission, both soldiers and shooters began swapping out uppers, buttstocks, handguards, sighting systems, flash suppressors and suppressors willy-nilly. We are definitely headed into a modular world of firearms in which form follows function and right at the head of the flexible shotgunning pack is Mossberg. Modifying their already modular Model 500/590 pump shotgun series, Mossberg has created a fascinating array of low-cost optional assemblies and a unique quick-change system they call “FLEX.”

Mossberg’s FLEX system was originally developed with a military application in mind. The military had made it known they were interested in a modular shotgun. Mossberg’s rugged and utterly reliable Model 590A1 pump gun already was the US military’s primary fighting shotgun, as it has been here for the last 25 years and currently in 41 other countries as well, so Mossberg moved vigorously ahead to design a flexible shotgun system that would put them in first place for the next 25 years. Then the climate changed.

For whatever reason, budgetary or otherwise, military interest in the modular shotgun concept waned so Mossberg moved the project to a back burner where it simmered for 7 years.

Holt rotated between a 24" turkey barrel and a 24" slug barrel during the hunt with the
new Mossberg FLEX 500 shotgun, shooting Hornady’s new Heavy Magnum Turkey loads
and SST slugs. Both loads excelled as game getters.

The Time Is Ripe

Then 2 or 3 years ago, the Mossberg family moved it once again to the front burner with the growing, sporting consumer market in mind. The result is impressive as will be its marketing through major dealers. There are currently 11 12-gauge models being offered in the FLEX system format and 16 complementing accessories with more becoming available based on consumer interest and demand. The models can be sorted out into three groups—all-purpose, hunting and tactical.

The key to the FLEX system is its “Tool-less Locking System,” actually systems. Mossberg brands it their “TLS.” What the TLS offers did to shoot it loose with magnum slug loads and muscle it around, that joint didn’t even creak.

Buttstocks include the infamous Mossberg “Cruiser” pistol grip, three standard, black or camo, synthetic stocks with length-of-pulls of 12-1/2″, 13-1/2″ and 14-1/2″; a 4-position hunting stock adjustable from 12-3/4″ to 14-5/8″ LOPs and two comb heights; and a 6-position, adjustable tactical stock offering LOPs from 11″ to 14-1/4″.

The second part of the TLS is a pushbutton system at the toe of the buttstock. Pushing it in permits you to pop off the existing recoil pad and pop on another size. There are three pad thicknesses available—3/4″, 1-1/4″ and 1-1/2″—allowing you to switch out LOPs for seasonal clothing or for different size shooters.

The third switch in the TLS is located under the fore-end. Pressing it allows you to detach the fore-end from the action bars by simply pushing the fore-end forward and rotating it down. The system sure beats fussing with an ornery magazine cap screw and gives you a choice of standard black or camo fore-ends and a tactical fore-end featuring three Picatinny rails and two protected recesses for mounting pressure switches.

The final, intriguing component to this ensemble is Mossberg’s new adjustable shotgun trigger—the LPA or “Lightning Pump Action” trigger—adjustable from 3 to 7 pounds without creep. Similar in design to the earlier Savage Accutrigger, the center blade of the LPA has to be fully depressed to fire the gun. To me, a fully adjustable trigger on a modestly priced shotgun is a miracle come true. I can’t tell you how much a light, crisp trigger can mean to all your shotgunning activities.

Changing stocks takes seconds with Mossberg’s FLEX system by lifting the
locking latch behind the top tang safety.

Then twist the latch and pull off the stock.

And pull off the stock.

FLEX Afield

I’m impressed with the concept and the quality of its execution. At the invitation of Mossberg’s Linda Powell, I had an opportunity to work with the FLEX systems while hunting turkeys and wild boar with Mellon Creek Outfitters on a ranch near Corpus Christi, Texas. I might add the Mellon Creek guides proved to be exceptionally talented in calling in trophy toms and locating the wily wild boar.

For turkeys, I chose Mossberg’s FLEX 500 Hunting model with a 24″ ported barrel tubed with a tight .670″ Accu-Choke and mounted with fiber optic sights and an LPA trigger. The metal was finished in very pleasing OD green while the stocks were cloaked in Mossy Oak Break-Up Infinity camouflage. My turkey load was Hornady’s brand new 3″ Heavy Magnum Turkey shell packed with 1-1/2″ ounces of nickel-plated No. 5 shot at 1,300 fps. At 35 yards, the new shell really hammered the patterning target, and it went on to hammer three early morning toms before the hunt was over.

The Hornady 300-grain SST slug at 2,000 fps proved to be a devastating big-game load.

Hornady’s 1-1/2 ounces of nickel-plated No. 5 shot simply hammered the turkey-patterning target.

It hammered a tom turkey later, too. The slug barrel generated rifle-sized 1-1/2"
groups with Hornady’s SST slug at 100 yards.


Toward mid-afternoon, I would switch out the turkey tube for a 24″ rifled and ported slug tube mounted with a quality Swarovski Z6i 1.7-10×42 scope with an illuminated reticle. Swarovski also loaned me a pair of CL Companion 8×30 binoculars that proved invaluable for picking up toms and boars in the dense vegetation of the ranch. My slug load was another Hornady product, their SST label, 300-grain, Flex Tipped slug at 2,000 fps. The Hornady catalog boasts about 2″ groups with the SST at 100 yards. My Mossberg/Swarovski/Hornady combination proved capable of cutting 1-1/2″ for 3-shot groups at 100 yards which speaks pages about the rigidity of the FLEX models plus the slugger put down two sizable boars at 30 and 50 yards respectfully with no argument whatsoever.

During the off hours of the hunt, I played “change-it” with a variety of FLEX stock and pad combinations Mossberg had sent along. It’s a simple and straight-forward system. You know that adage about “Beware the man with one gun.” This could be that one gun that instills familiarity and confidence and conserves cash. For a family, it could fill a niche for all ages and all purposes from clays to hunting to tactical home protection. Don’t be surprised if a 20 gauge isn’t added to the FLEX family soon or maybe even an autoloader.

MAKER: O.F. Mossberg & Sons, Inc.
7 Grasso Ave.
P.O. Box 497
New Haven, CT 06473
(800) 363-3555

FLEX 500 All Purpose
Price: $593
FLEX 500 Tactical (OD Green)
Price: $887, RECOIL PADS: $24,
FORE-ENDS: $33 to $46, STOCKS: $156
(4-position hunting), $108 (6-position tactical stock)

Mellon Creek Outfitters
(361) 484-2398

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