he firearms market is changing.
While recent headlines have focused on firearms that owners are becoming reluctant to sell, the more interesting question may be what today's shooters will wish they had kept five or ten years from now.
Traditionally, that conversation has centered on classic lever-action rifles, older revolvers, military-surplus firearms and discontinued models.
But there's another category worth watching in 2026:
Firearms chambered in emerging calibers.
At Moriarti Armaments, we've watched cartridges such as .338 ARC, 8.6 Blackout, .400 Legend, .350 Legend, .22 ARC and 6.8 SPC II create new niches within AR-platform shooting.
Nobody can predict which modern firearm will become tomorrow's collectible. But history repeatedly demonstrates that once a particular configuration, caliber or production run disappears, replacing it can become much harder.
And right now, the firearms market is producing some very interesting candidates.
Why Are Gun Owners Holding Onto Certain Firearms?
The used-firearm market remains extremely active.
July 2026 produced more than 2,000 firearm offers and 747 completed purchases in We Buy Guns' nationwide secondary-market data—the company's highest activity levels of 2026 at that point. Premium and collector-oriented firearms also continued to command significantly higher values than ordinary mass-market models.
But price isn't the only reason owners hesitate to sell.
Sometimes the bigger question is:
“If I sell this firearm today, will I be able to find this exact configuration again?”
That question becomes especially relevant with unusual calibers and specialized AR configurations.
The Traditional Keepers: Classics, Collectibles and Discontinued Guns
There will always be established categories that firearm owners think twice about selling.
Older premium revolvers, classic lever actions, military-surplus firearms, desirable bolt guns and limited-production models all have something in common:
Supply isn't unlimited.
Once production changes or stops, the market has to work with whatever already exists.
But that same principle can apply to much newer firearms.
A rifle doesn't have to be 50 years old before its configuration becomes difficult to replace.
The New Category to Watch: Emerging-Caliber Firearms
This is where the 2026 market gets particularly interesting.
A new generation of cartridges is changing what shooters can accomplish with AR-15 and AR-10-size platforms.
Industry coverage this year is already pointing toward continued development of newer chamberings. Current 2026 rifle introductions include platforms chambered for .400 Legend and .22 ARC, with additional .338 ARC offerings entering the market.
The question isn't whether every new caliber will become collectible.
They won't.
The question is which cartridges will develop a large enough ecosystem of ammunition, barrels, magazines, uppers, suppressors and complete firearms to establish staying power.
Those are the ones worth watching.
.338 ARC: One of the Most Interesting AR-15 Calibers Right Now
Few emerging cartridges illustrate this better than .338 ARC.
Instead of requiring a larger AR-10-size platform, .338 ARC brings heavy .338-caliber projectile capability to the AR-15 platform.
Its combination of subsonic ammunition, supersonic ammunition and suppressor-oriented performance has given it a very distinct position in the market. Recent industry coverage specifically describes .338 ARC as optimized around heavy payloads and suppressed performance from the standard AR-15 platform.
And the ecosystem is growing.
Moriarti now has an expanding .338 ARC family encompassing:
.338 ARC kits → uppers → barrels → magazines → ammunition → .338-cal suppressors
That's significant.
A caliber becomes much more interesting when it develops beyond one firearm or one ammunition loading into a complete ecosystem.
We're already seeing that happen with .338 ARC.
8.6 Blackout: The Large-Frame Suppressed Alternative
Then there's 8.6 Blackout.
While .338 ARC brings heavy .338-caliber projectiles into an AR-15-size platform, 8.6 Blackout generally operates in the larger AR-10/short-action ecosystem.
The cartridge has gained attention because of its combination of short-barrel capability, heavy projectiles and subsonic/supersonic ammunition options.
It has also continued maturing. Industry reporting in 2026 notes that 8.6 Blackout has now achieved SAAMI standardization, removing one of the uncertainties that had previously slowed broader manufacturer adoption.
For Moriarti, that makes .338 ARC and 8.6 Blackout especially interesting side by side.
One serves the AR-15 ecosystem.
The other serves the larger platform.
Both reflect the rapidly growing relationship between modern cartridges, short barrels, heavy projectiles and suppressors.
.400 Legend: Straight-Wall Hunting Continues to Evolve
Not every emerging caliber is about suppressed shooting.
.400 Legend represents another major trend: the continuing development of straight-wall hunting cartridges.
It occupies the space between .350 Legend and .450 Bushmaster and is increasingly appearing in new factory rifles. NSSF's 2026 product coverage, for example, includes new .400 Legend chamberings from established manufacturers.
For AR owners, that creates another evolving ecosystem:
.350 Legend → .400 Legend → .450 Bushmaster
Each provides a different balance of recoil, projectile size, energy and application.
That's exactly the type of specialized market where certain configurations can eventually become difficult to replace.
.22 ARC: Another New Cartridge Building Manufacturer Support
At the opposite end of the spectrum is .22 ARC.
Rather than emphasizing large projectiles, .22 ARC targets high-velocity, high-BC .22-caliber performance.
What's important from a market perspective is that manufacturers continue adding support.
New 2026 rifle introductions include factory .22 ARC chamberings, providing another indication that the cartridge is moving beyond its initial launch phase.
Again, that doesn't guarantee future collector value.
It demonstrates something more useful:
The ecosystem is expanding.
What Moriarti Is Watching
At Moriarti Armaments, emerging calibers have become an increasingly important part of our AR-platform lineup.
We're particularly watching:
.338 ARC — heavy .338-caliber performance from the AR-15 platform, including strong subsonic and suppressor interest.
8.6 Blackout — heavy .338-caliber performance from the larger AR platform with a growing suppressed-shooting ecosystem.
.400 Legend — a newer straight-wall option positioned between established .350 Legend and .450 Bushmaster applications.
.22 ARC — high-performance .22-caliber ammunition designed around modern rifle platforms.
6.8 SPC II — not a new cartridge, but an alternative AR-15 caliber with an established following that remains relevant as shooters look beyond 5.56 NATO.
And then there is 300 Blackout.
300 BLK provides a useful lesson about emerging calibers because it was once the unusual new cartridge.
Today, it has an enormous ecosystem of ammunition, barrels, uppers, magazines, complete firearms and suppressors.
That evolution is exactly why newer calibers shouldn't automatically be dismissed simply because their current market is smaller.
Should You Keep an Emerging-Caliber Firearm?
There is no guarantee that a .338 ARC, 8.6 Blackout, .400 Legend or .22 ARC firearm purchased today will become collectible.
That's not the point.
A better question is whether the firearm would be difficult or expensive to recreate later.
Consider the combination of caliber, barrel length, manufacturer, finish, receiver configuration and other factory characteristics.
If the configuration is unusual and you genuinely enjoy owning it, selling simply because the caliber isn't mainstream yet can create future regret if the platform later becomes popular—or disappears.
The same applies in reverse.
Some experimental cartridges never achieve widespread adoption.
That's part of what makes emerging calibers interesting.
Today's Oddball Could Be Tomorrow's Classic
Every established firearm or cartridge was new once.
Some disappear.
Some survive as small enthusiast niches.
And a select few become permanent parts of the firearms landscape.
The current secondary market shows that firearm owners continue buying and selling aggressively, while premium and enthusiast-oriented firearms occupy a very different portion of the market from ordinary commodity models.
For collectors and enthusiasts, therefore, the smartest question isn't necessarily:
“Which gun will increase the most in value?”
It may be:
“Which firearm would I regret trying to replace five years from now?”
For some shooters, that's an old lever gun or revolver.
For others, it may turn out to be an unusual AR chambered in a caliber that is only beginning to establish itself today.
And in 2026, .338 ARC, 8.6 Blackout, .400 Legend and .22 ARC are four of the emerging calibers we'd keep an eye on.
