In a world where micro-compact pocket pistols seem to rule, it is easy to forget that size does matter. While extremely compact handguns have always had a niche, it was full-sized and large handguns that were relied on first and foremost throughout history.

There is, however, no reason we can’t up the ante and turn even “standard” handguns into much more effective defensive weapons. Enter the megapistol, the trunk gun, the briefcase commando. Call it what you will, but these semi-automatic pistols deliver higher-powered ammunition, greater velocity, larger magazine capacities, improved accuracy, longer-range effectiveness and easy accessorizing, and sometimes all of the above. And, by selecting powerful chamberings with larger-diameter projectiles than the commonly found 5.56mm NATO round, you can have an intriguing option for a defensive gun. Whether it is for home or travel, a megapistol may fill a necessary, life-saving niche in your self-defense arsenal.

DoubleStar AR Pistol

DoubleStar produces AR pistols in 300 Blackout (and 5.56mm NATO) in two different barrel lengths: 7.5 and 9 inches. Featuring direct gas impingement systems for reliable operation, the powerful AR-platform pistols are available with a variety of options in each barrel length. These include flattop upper receivers, chrome-lined barrels, low-profile gas blocks, quad-rail handguards and enhanced flash suppressors, to name just a few. For those looking for a powerful megapistol that can be customized to their exact requirement, DoubleStar definitely deserves a very close look. (star15.com; 888-736-7725)

CZ Scorpion EVO 3 S1 Pistol

The CZ Scorpion EVO 3 S1 Pistol is a semi-auto powerhouse chambered in 9mm. Based on a venerable submachine gun, this is one megapistol that keeps things simple by allowing you to use the same ammunition as your normal carry gun, plus the longer 7.72-inch barrel adds extra velocity to the standard 9mm ammunition. Along the top of the receiver is an 11-inch Picatinny rail for installing optics and sights. Fully adjustable low-profile diopter sights are included and can be easily removed. The pistol features an ambidextrous magazine release and safety as well as a reversible changing handle. The Scorpion ships with two translucent, 20-round magazines, but 30-round magazines are also available from CZ-USA. (cz-usa.com; 800-955-4486)

Sig Sauer MPX-P

This fully ambidextrous, semi-automatic, piston-operated megapistol is designed to mimic an AR in its controls and operation. The upper and lower receivers are both made from aluminum so that it is surprisingly lightweight. The MPX-P is also incredibly modular. The handguard can be removed without any tools and easily replaced. A Torx wrench can also be used to quickly remove the MPX’s barrel/gas piston assembly, giving the user a choice of installing 4.5-, 6.5- or 8-inch barrels. With the 8-inch barrel and standard handguard, only the flash suppressor is exposed, and there is a full 14 inches of uninterrupted Picatinny rail space on top for optics. The threaded barrel is also suppressor ready. (sigsauer.com; 603-310-3000)

Sig Sauer P716 Pistol

Sig Sauer has been in the firearms business for over 150 years, with most of that time focused on producing military arms. Sig’s pistols are a favorite among law enforcement, and in recent years the company has offered a complete line of megapistols as well. The P716 is a true big-bore megapistol chambered in 7.62 mm NATO. It features a 12.5-inch, free-floating barrel, an adjustable gas piston system and AR controls. It accepts Magpul PMAGs and comes with flip-up sights as well as an SB-15 stabilizing brace. (sigsauer.com; 603-310-3000)

ASA 7.5 Side Charging Pistol

American Spirit Arms (ASA), based out of Scottsdale, Arizona, is best known for its non-reciprocating, side-charging designs. The ASA 7.5 Side Charging Pistol is based on a standard AR design but has no stock, just a foam-sleeve-covered buffer tube that can be used as a check rest, and a short 7.5-inch barrel with a 1-in-14-inch twist rate. The free-floating Samson handguard is easy to customize, as it accepts accessory rails where needed, and the long Picatinny top rail is ready for sights and optics. (americanspiritarms.com; 480-367-9540)

Daniel Defense DDM4300

Daniel Defense’s entry into the big-bore megapistol market is the DDM4 in 300 BLK. This heavy-duty pistol comes complete with a 10.3-inch, cold-hammer-forged barrel with Daniel Defense’s S2W profile, a pistol-length gas system, a pinned low-profile gas block and a DDM4 handguard. AR users have long been fans of Daniel Defense’s rugged, high-quality products, and the DDM4300 pistol should make a great addition to the collection of any shooter looking for a powerful and compact megapistol. (866-554-4867; danieldefense.com)

Yankee Hill Machine YHM-8030

Yankee Hill Machine (YHM) has greatly expanded its line of innovative rifles and suppressors to include new megapistols. One of the latest of these is the YHM-8030 chambered in 300 Blackout. The pistol features a free-floating, Melonite-treated, 9.1-inch barrel with a Phantom Flash Hider. The carbine-length KeyMod handguard makes adding accessories a simple proposition, and the E-Z Pull takedown pins simplify maintenance. The 300 Blackout is ideal for suppressed use with subsonic ammunition. YHM also offers 9mm and .223 pistol versions. (yhm.net; 877-892-6533)

Rock River Arms LAR-9 Pistol

Rock River Arms AR pistols are available in both 7- and 10.5-inch-barreled flattop configurations. Options include A2-style uppers, chromed bolt carriers, free-floating rail systems and much more. All variants come equipped with Hogue rubber pistol grips. The LAR-9 combines familiar AR-platform operation with the 9mm cartridge and a reliable, straight-blowback operating system. The result is an appealing megapistol ready for the range or heavy-duty defensive use. (866-980-7625; rockriverarms.com)

MRI Desert Eagle Mark XIX

Desert Eagles are huge, gas-operated, rotating-bolt pistols that handle everything from .357 Magnum to .50 AE cartridges. You could say that they might be the original megapistol. Now Magnum Research Inc. (MRI) is producing Desert Eagles in custom animal prints to really bring out your wild side. These pistols are available in cheetah, snake and zebra prints, as well as Kryptek Highlander and Kryptek Typhon camo in .357 Magnum, .50 AE or .44 Magnum. The built-in Picatinny accessory rail above the barrel makes it easy to add sights and optics for increased accuracy downrange. (magnumresearch.com; 508-635-4273)

MasterPiece MPA10SST

Packing hard-hitting .45 ACP power and a 30+1 capacity, the MPA10SST from MasterPiece Arms is a definite contender. The straight-blowback pistol is simple, rugged and powerful. The top of the pistol features a strip of Picatinny rail for optics, while a side-mounted cocking handle makes it easy to chamber a round. The barrel is threaded for suppressor use, and a tough Parkerized finish protects against corrosion. Its tough construction and impressive firepower ensure the MPA10SST will deliver when it counts. (masterpiecearms.com; 866-803-0000)

IWI Uzi Pro Pistol

The new Uzi Pro Pistol from IWI is another example of how the 9mm round can be well suited for the megapistol role. Unlike a full-sized 9mm duty pistol, the Uzi Pro Pistol virtually eliminates perceived recoil thanks to its weight and design. The standard 20- and 25-round magazines provide plenty of firepower without adding too much bulk, and the Picatinny rails on top of the receiver and forward of the triggerguard offer the shooter plenty of versatility for optics, lights and lasers. The Uzi Pro Pistol also features grip and thumb safeties as well as a left-side-mounted charging handle. The basic blowback-operated design of the Uzi also ensures reliability shot after shot, even with heavy fouling. (iwi.us; 717-695-2081)